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document number: mma7660fc rev 8, 03/2012 freescale semiconductor data sheet: technical data an energy efficient solution by freescale ? 2009-2012 freescale semiconducto r, inc. all ri ghts reserved. 3-axis orientation/motion detection sensor the mma7660fc is a 1.5 g 3-axis accelerometer with digital output (i 2 c). it is a very low power, low profile capacitive mems sensor featuring a low pass filter, compensation for 0g offset and gain errors, and conversion to 6-bit digital values at a user configur able samples per second. the device can be used for sensor data changes, product orientation, and gesture detection through an interrupt pin (int ). the device is housed in a small 3mm x 3mm x 0.9mm dfn package. features ? digital output (i 2 c) ? 3mm x 3mm x 0.9mm dfn package ? low power current consum ption: off mode: 0.4 a, standby mode: 2 a, active mode: 47 a at 1 odr ? configurable samples per second from 1 to 120 samples a second. ? low voltage operation: ? analog voltage: 2.4 v - 3.6 v ? digital voltage: 1.71 v - 3.6 v ? auto-wake/sleep feature for low power consumption ? tilt orientation detection for portrait/landscape capability ? gesture detection including shake detection and tap detection ? robust design, high shocks survivability (10,000 g) ? rohs compliant ? halogen free ? environmentally preferred product ? low cost typical applications ? mobile phone/ pmp/pda: orientatio n detection (portrait/landscape), image stability, text scroll, motion dialing, tap to mute ? laptop pc: anti-theft ? gaming: motion detection, auto-wake/sleep for low power consumption ? digital still camera: image stability ordering information part number temperature range package shipping mma7660fct ?40 to +85c dfn-10 tray mma7660fcr1 ?40 to +85c dfn-10 7? tape & reel n/c dvdd dvss sda scl reserved n/c avdd avss int 1 2 3 4 5 6 7 8 9 10 figure 1. pin connections reserved 10 lead dfn case 2002-03 mma7660fc mma7660fc: xyz-axis accelerometer 1.5 g bottom view top view
sensors freescale semiconductor 2 mma7660fc contents definitions ................................................................................................................... ............................................................ 5 electro static discharge (esd) ................................................................................................ ...................................... 7 principle of operation ........................................................................................................ .............................................. 9 modes of operation ............................................................................................................ .............................................. 10 configurable samples per seconds and interrupt settings ....................................................................... .. 11 power saving features ..... .............................................................................. ............ .......... .......................................... 11 testing the logic chain ....................................................................................................... ............................................ 11 features ...................................................................................................................... .......................................................... 11 tap detection ................................................................................................................. ..................................................... 13 shake detection ............................................................................................................... ................................................... 13 auto-wake/sleep ............................................................................................................... ................................................. 13 register definitions .......................................................................................................... ............................................... 14 serial interface .............................................................................................................. ................................................... 22 serial-addressing ............................................................................................................. ................................................... 22 start and stop conditions ..................................................................................................... .............................................. 22 bit transfer .................................................................................................................. ........................................................ 22 acknowledge ................................................................................................................... .................................................... 23 the slave address ............................................................................................................. ................................................. 23 message format for writing mma7660fc ................................................................................. ......... ................................ 23 message format for reading mma7660f c .......................................................................................... .............................. 24 appendix a - package requirements for mma7660fc ....... .................................................. ............ .......... .............. 25 minimum recommended footprint for surface mounted applicat ions .......... .......................................... ............ ............... 25 soldering and mounting guidelines for the dfn accelerometer sensor to a pc board ........ ............................ .......... ...... 25 overview of soldering considerations ................. ......................................................................... ...................................... 25 halogen content ............................................................................................................... .................................................. 25 pcb mounting recommendations ............................ ...................................................................... .................................... 25 appendix b - sensing direction ...... .............................................................................. ............ ...................................... 27 appendix c - mma7660fc acquisition code table ....... ................................................................ .......... .................... 28 appendix d - i 2 c ac characteristics .......................................................................................................... .................. 30
sensors freescale semiconductor 3 mma7660fc list of tables pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 esd and latch-up protection characteristi cs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 operating characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 modes of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 feature summary table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 orientation detection logic of when interrupt will occur . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 auto-wake/sleep truth table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 user register summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 ase/awe conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 sleep counter timeout ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 i 2 c ac characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
sensors freescale semiconductor 4 mma7660fc list of figures i 2 c connection to mcu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 simplified accelerometer functional block dia gram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 simplified transducer physical model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 state machine of modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 orientation detection logic in 3-dimensional space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2-wire serial interface timing de tails . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 start and stop conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 bit transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 acknowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 slave address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 single byte write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 multiple bytes write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 single byte read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 multiple bytes read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 package footprint, pcb land pattern, and stencil design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 pcb land pattern detail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 product orientation on perpendicular axis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 product orientations showing direction for each axis in compos ite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
sensors freescale semiconductor 5 mma7660fc definitions auto-wake: sleep mode (uses amsr sample rate in sr [0x08] register) auto-sleep: run mode (uses awsr sample rate in sr [0x08] register) pmp: portable media player pda: personal digital assistant dfn: dual flat no lead esd: electro static discharge odr: output data rate mems: microelectromechanical systems
sensors freescale semiconductor, inc. 6 mma7660fc figure 1. pinout table 1. pin description figure 2. i 2 c connection to mcu reserved dvdd dvss sda scl reserved n/c avdd avss int top view 1 2 3 4 5 6 7 8 9 10 pin # pin name description pin status 1 reserved connect to avss input 2 n/c no internal connection, leave unconnected or connect to ground input 3 avdd device power input 4 avss device ground input 5int interrupt/data ready output 6scl i 2 c serial clock input 7sda i 2 c serial data open drain 8 dvss digital i/o ground input 9 dvdd digital i/o power input 10 reserved connect to avss input reserved dvdd dvss sda scl reserved n/c avdd avss int 1 2 3 56 7 8 9 10 4 gnd vdd vdd vdd gnd mma7660fc sda scl int mcu r1 4.70 k r2 4.70 k note: a 0.1 f ceramic capacitor can be placed connecting pin 3 ( avdd) to pin 4 (avss). in addition, another 0.1 f ceramic capacitor can be place connecting pin 9 (dvdd) to pin 8 (dvss). the capacitors should be placed close to the pins of the mma7660fc and is recommended for testing and to adequately decouple the accelerometer from noise on the power supply. u13
sensors 7 freescale semiconductor, inc. mma7660fc figure 3. simplified acceleromet er functional block diagram electro static discharge (esd) warning: this device is sensitive to electrostatic discharge. although the freescale accelerometer contains internal 2000 v esd protection circuitry, extra precaution must be taken by the user to protect the chip from esd. a ch arge of over 2000 v can accumulate on the human body or associated test equipment. a charge of this magnitude can alter the pe rformance or cause failure of the chip. wh en handling the accelerometer, proper esd precautions should be followed to avoid exposing the device to discharges which may be detrimental to its performance. table 2. maximum ratings (maximum ratings are the limits to which the device can be exposed without causing permanent damage.) rating symbol value unit maximum acceleration (all axes, 100 s) g max 10,000 g analog supply voltage av dd -0.3 to +3.6 v digital i/o pins supply voltage dv dd_io -0.3 to +3.6 v drop test d drop 1.8 m storage temperature range t stg -40 to +125 c table 3. esd and latch-up protection characteristics rating symbol value unit human body model hbm 2000 v machine model mm 200 v charge device model cdm 500 v latch-up current at t a = 85c 100 ma avdd dvdd vss x-axis transducer y-axis transducer z-axis transducer mux control logic int c-to-v converter amp adc sda scl offset trim gain trim i 2 c internal osc clock gen
sensors freescale semiconductor, inc. 8 mma7660fc notes 1. these parameters are tested in production at final test. 2. assuming vdd power on slope is < 1 ms. 3. a measure of the devices ability to reject an acce leration applied 90 from the true axis of sensitivity. 4. noise is defined as quantiles given to a sa mple size. these are the occurrences of noise: 94% = 1 count, 5% = 2 counts, and 1% = 3 counts. table 4. operating characteristics unless otherwise noted: -40c < t a < 85c, 2.4 v < av dd < 3.6 v, 1.71 v < dv dd < 3.6 v, acceleration = 0g typical values are at av dd = 2.8 v, dv dd = 2.8 v, t a = +25c characteristics symbol min typ max unit analog supply voltage standby/operation mode av dd 2.4 2.8 3.6 v enable bus modeon mode av dd 0 v digital i/o pins supply voltage standby/operation mode dv dd_io 1.71 2.8 av dd v enable bus modeon mode dv dd_io 1.71 1.8 3.6 v supply current drain off mode i dd 0.4 a power down mode i dd 2 a standby mode (1) i dd 0 2 10 a active mode, odr = 1 i dd 47 a active mode, odr = 2 i dd 49 a active mode, odr = 4 i dd 54 a active mode, odr = 8 i dd 66 a active mode, odr = 16 i dd 89 a active mode, odr = 32 i dd 133 a active mode, odr = 64 i dd 221 a active mode (1) , odr = 120 i dd 294 a acceleration range 1.5 g operating temperature range t a -40 25 85 c 0g output signal (t a = 25c, av dd = 2.8 v) 0g offset 1.5g range (1) v off -3 0 3 counts 0g offset temperature variation x y z -1.3 +1.5 -1.0 mg/c mg/c mg/c sensitivity (1) (t a = 25c, av dd = 2.8 v) 1.5g range 6-bit 21.33 count/g acceleration sensitivity at t amb 19.62 21.33 23.04 count/g acceleration sensitivity temperature variation 0.01 %/c input high voltage v ih 0.7 x d vdd input low voltage v il 0.35 x d vdd output low voltage (iol = 6 ma + sda, int ) v ol 0.5 v input leakage current i ih , i il 0.025 a internal clock frequency (1) (t a = 25c, av dd = 2.8 v) t clk 135 150 165 khz i 2 c interface speed 400 khz control timing turn on time from av dd = 0 v to av dd = 2.5 v (2) 1.3 ms turn off time from active to standby mode 1 ms turn on time standby to active mode 12 ms + 1/odr ms timing clock source accuracy (t a = 25c, dv dd = 1.8 v) -10 10 % timing clock source temperature variation -15 15 % cross axis sensitivity (3) 1 % noise (4) 1 count
sensors 9 freescale semiconductor, inc. mma7660fc principle of operation the freescale accelerometer consists of a mems capacitive sensing g-cell and a signal conditioning asic contained in a single package. the sensing element is sealed hermetically at the wafer level using a bulk micro machined cap wafer. the g-cell is a mechanical structure formed from semiconductor ma terials (polysilicon) using masking and etching processes. the sensor can be modeled as a movable beam that moves between two mechanically fixed beams ( figure 4 ). two gaps are formed; one being between the movable beam and the first statio nary beam and the second betw een the movable beam and the second stationary beam. the asic uses switched capacitor techniques to measure the g-ce ll capacitors and extract the acceleration data from the difference between the two capacitors. the asic also signal condi tions and filters (switched capaci tor) the signal, providing a digital output that is pr oportional to acceleration. figure 4. simplified transducer physical model acceleration
sensors freescale semiconductor, inc. 10 mma7660fc modes of operation the sensor has three power modes: off mode, standby mode, and active mode to offer t he customer different power consumption options. the sensor is only capabl e of running in one of these modes at a time. the off mode offers the lowest power consumption, approximate ly 0.4 a and can only be reached by powering down the analog supply. see figure 5 . in this mode, there is no analog supply and all i 2 c activity is ignored. the standby mode is ideal for battery operated products. when standby mode is active the device outputs are turned off providing a significant reduction in oper ating current. when the device is in st andby mode the current will be reduced to approximately 3 a. standby mode is entered as soon as both a nalog and digital power supplies are up. in this mode, the device can read and write to the registers with i 2 c, but no new measurements can be taken. the mode of the device is controlled through the mode (0x07) control register by acce ssing the mode bit in the mode register. during the active mode, continuous measur ement on all three axes is enabled. in ad dition, the user can choose to enable: shake detection, tap detection, orientati on detection, and/or auto-wake/sleep featur e and in this mode the digital analysis for any of these functions is done. the user can configure the samples per second to any of the following: 1 sample/second, 2 samples/second, 4 samples/second, 8 samples/second, 16 sa mples/second, 32 samples/second, 64 samples/second, and 120 samples/second, for the auto-sleep st ate. if the user is configuring the auto -wake feature, the se lectable ranges are: 1 sample/second, 8 samples/second, 16 samples/seconds a nd 32 samples/second. depending on the samples per second selected the power consumption will vary. figure 5. state machine of modes table 5. modes of operation measurement and power mode i2c bus dvdd avdd function power down mode dvdd is down, so i 2 c bus cannot be used for other devices (mma7660fc clamps i 2 c bus to dvvd pin) off off mma7660fc is powered down in both supplies. i 2 c activity is unavailable on bus. off on mma7660fc is powered down in digital supply but not analog supply. i 2 c activity is unavailable on bus. avdd power cycling requires 50 msec. off mode mma7660fc will not respond, but i 2 c bus can be used for other devices (mma7660fc does not load i 2 c bus) on off mma7660fc is powered down in analog supply but not digital supply. i 2 c activity is ignored. standby mode mma7660fc will respond to i 2 c bus on on mma7660fc is powered up in both supplies, so registers can be accessed normally to set mma7660fc to active mode when desired. mma7660fc's sensor measurement system is idle. active mode auto-sleep auto-wake mma7660fc will respond to i 2 c bus on on mma7660fc is able to operate s ensor measurement system at user programmable samples per second and run all of the digital analysis functions. tap detection operates in active mode and auto-sleep, but not auto-wake.
sensors 11 freescale semiconductor, inc. mma7660fc configurable samples per seconds and interrupt settings the device can be configured into 8 different samples per seconds including: 1 sample/second, 2 samples/second, 4 samples/second, 8 samples/se cond, 16 samples/second, 32 samples/second, 64 samples/second, and 120 samples/second, the user can specify the samples per second for their particular application, deciding on the trade off between power consumption and number of samples, this can be configured in the sr (0x08) register . once the user conf igurable samples per second is chosen, the device will update the data for all 3 axes in the register at a resolution of 6-bits/axis. the user can choose to enable/disable any of the following interrupts in the intsu (0x06) register: front/back interrupt, up/down/left/right interrupt, tap detection interrupt, gint (real -time motion tracking), shake on x-axis, shake on y-axis, and shake on z-axis. if the gint is enabled, real-time motion tra cking can be configured to trigger an interrupt after every sensor data update: 1s (1 sample/second), 500 ms (2 samples/second ), 250 ms (4 samples/second), 125 ms (8 samples/second), 62.5 ms (16 samples/second), 31.25 ms (32 samples/second), 15.625 ms (64 sample s/second), or 8.36 ms (120 samples/ second). if any of the shake axis interrupts are enabled; excessive agitation, greater than 1.3 g, will trigger an interrupt. i f either the up/down/left/right interrupt or the front/back interrupt is enabled, any change in orientation will generate an interrupt. when the auto-wake feature is enabled, and the auto -sleep counter elapses an interrupt will occur. when the device is in auto-sleep state, if a shake interrupt, tap interrupt, delta g, or orientation detection interr upt occur, the device will go out of sleep state and into wake state. power saving features the mma7660fc includes a range of user configurable power saving features. the device?s samples per second can be set over a wide range from 1 to 120 samples a second; the operatin g current is directly proportional to samples per second. the analog supply a vdd can be powered down to put the mma7660fc into off mode, which typically draws 0.4 a. the auto-wake/ sleep feature can toggle the sampling rate from a higher user selected samples per second to a lower user selected samples per second, changing based on if motion is det ected or not. the user can choose to us e any of the above options to configure the part and make it have the optimal power consumption level for the desired application. testing the logic chain mma7660fc can be put into test mode, which disables accele rometer measurements and instead allows the user to write 6-bit values directly to the three axis da ta registers, thus simulating real time accelerometer measurements. the state machine will respond to these values according to the enabled features and functions, allowing them to be validated. note: mma7660fc does not include an accelerometer self test function, which is typically an electrostatic force applied to each axis to cause it to deflect. features the sensor employs both analog and digital filtering to ensure low noise and accurate output when using the part for shake, tap, or orientation detection. during active mode, the data is filtered and stored for each of the 3 axes at the specified foll owing measurement intervals: 1s (1 sample/second), 500 ms (2 samples/second), 250 ms (4 samples/second), 125 ms (8 samples/second), 62.5 ms (16 samples/second), 31.25 ms (32 samples/se cond), 15.625 ms (64 samples/second), or 8.36 ms (120 samples/second) or indicated in amsr [2:0]. the 6-bit measurement data is stored in the xout (0x00), yout (0x01), and zout (0x02) registers and is used to update the shake, alert, tap, pola[2:0] (updates up, down, left, and right positi on), and bafro[1:0] (updates back and front position) in the tilt (0x03) register used for orientation detection. t he customer can configure the part by enabling a number of user- desired interrupts in the intsu (0x06) register. once the in terrupts are enabled a change in filtered readings will cause an interrupt to occur depending on the output. the filters that are being used by this sens or is the analog filtering, digital noise filtering of measurem ents used for orient ation detection and updated in the xout (0x00), yout (0x01), and zout (0x02) registers. the filterin g method used is to oversample each axis by taking 32 readings, and then calculate the average for t he output measurement data as a finite impulse response filter. note: sensor measurements are not taken in standby mode or in test mode. table 6. feature summary table feature will generate interrupt orientation change when fbint, plint = 1 shake when shintx, shinty, shintz = 1 tap or tilt when pdint = 1 auto-wake/sleep when asint = 1 x, y, z data update when gint = 1
sensors freescale semiconductor, inc. 12 mma7660fc orientation detection orientation detection logic mma7660fc gives the customer the capability to do orientatio n detection for such applications as portrait/landscape in mobile phone/pda/ pmp. the tilt orientati on of the device is in 3 dimensions and is id entified in its last known static positio n. this enables a product to set its display orientation appropriately to either portrait/landscape mode, or to turn off the display if the product is placed upside down. the sensor provides six differen t positions including: left, right, up, down, back, and front, shown in ta b l e 7 . in active mode the data is processed and updates the or ientation positions in the tilt (0x03) register. at each measurement interval, it computes new values for left, right, up, down, back, and front but it does not automatically update these bits in the tilt (0x03) register. these values are upd ated depending on the debounce filter settings (sr register 0x08) configured by the customer. in order to give the customer the ability to configure the debounce filt er, specific to there application, they can change the following bits in the sr (0x08) register, filt [2:0]. please see below for a more detailed explanation of how the filt [2:0] wo rks in conjunction with updating the tilt (0x03) register: ? if filt [2:0] = 000, then the new values for left, right, up, do wn, back, and front are updated in the tilt (0x03) register (pola [2:0] and bafro [1:0]) after every reading without any further analysis. ? if filt [2:0] = 001 ? 111, then the sensor requires the computed values for left, right, up, down, back, and front to be the same from 1-7 consecutive readings (depending on the value in fi lt [2:0], before updating the values stored in tilt (0x03) register (pola [2:0] and bafro [1:0]). the debounce counter is re set after a mismatched reading or the tilt (0x03) register is updated (if the orientation condition is met). figure 6. orientation detection logic in 3-dimensional space table 7. orientation detection logi c of when interrupt will occur orientation xg yg zg shake |x| > +1.3g or |y| > +1.3g or |z| > +1.3g up |z| < 0.8g and |x| > |y| and x < 0 down |z| < 0.8g and |x| > |y| and x > 0 right |z| < 0.8g and |y| > |x| and y < 0 left |z| < 0.8g and |y| > |x| and y > 0 back z < -0.25g front z > 0.25g down up front back right left down up front back right left
sensors 13 freescale semiconductor, inc. mma7660fc tap detection the mma7660fc also includes a tap detection feature that can be used for a number of different customer applications such as button replacement. for example, a single tap can stop a song from playing and a double tap can play a song. this function detects a fast transition that exceeds a user-defined threshol d (pdet (0x09) register) for a se t duration (pd (0x0a) register). tap detection setup in order to enable tap detection in the device the user must enable the tap interrupt in the intsu (0x06) register and amsr [2:0] = 000 in the sr (0x08) register. in this mode, tilt (0x03) register, xout (0x0 0), yout (0x01), and zout (0x02) registers will update at the 120 samples/second. the user can configure tap detection to be detected on x a nd/or y and/or z axes. the cust omer can configure this by changing the xda, yda, and/or zda bit in the pdet (0x09) r egister. detection for enabled axes is decided on an or basis: if the pdint bit is set in the intsu (0x06) register, the device re ports the first axis for which it detects a tap by the tap bit in the tilt (0x03) register. when the tap bit in the tilt (0x03) regi ster is set, tap detection ceas es, but the device will continue t o process orientation detection data. tap detection will resume when the tilt (0x03) register is read. note: delta g is available with any amsr setting, when xd a = yda = zda = 1 (pdet = 1). when the sampling rate is less than 120 samples/second, the device can not detect tapping, but can detect small tilt angles (30 o angle change) which can not be detecte d by orientation detection. shake detection the shake feature can be used as a button replacement to per form functions such as scrolling through images or web pages on a mobile phone/pmp/pda. the customer can enable the shake interrupt on any of the 3 axes, by enabling the shintx, shinty, and/or shintz in the intsu (0x06) register. mma7660fc detects shake by examining the current 6-bit meas urement for each axis in xout, yout, and zout. the axes that are tested for shake detection are the ones enabled by sh intx, shinty, and/or shintz. if a selected axis measures greater that 1.3 or less than -1.3 g, then a shake is detected for that axis and an interrupt occurs. all three axes are checke d independently, but a common shake bit in the tilt register is set when shake is det ected in any one of the selected axes. therefore when all three (shintx, shinty, and/or shintz) are selected the sensor will not know what axis the shake occurred. when the tilt register is read the shake bit is cleared during the acknowledge bit of the read access to that register and shak e detection monitoring starts again. auto-wake/sleep the mma7660fc has the auto-wake/sleep feature that can be enabled for power saving. in the auto-wake function, the device is put into a user specified low samples per second (1 sample/second, 8 samples/second, 16 samples/second, or 32 samples/second) in order to minimize power consumption. wh en the auto-wake is enabled and activity is detected such as a change in orientation, pulse event, delta g acceleration or a shake event, then the device wakes up. auto-wake will automatically enable auto-sleep when the device is in wake mo de and can therefore be configured to cause an interrupt on wake-up, by configuring the part to either wake-up with a change in orientation, shak e, or if using the pa rt at 120 samples/sec ond tap detection. when the device is in auto-wake mode, the mode (0x07) register, bit awe is high. when the device has detected a change in orientation, a tap shake, or delta g (change in a cceleration), the device will enter auto-sleep mode. in the auto- sleep function, the device is put into any of the following us er specified samples per second s (1 sample/second, 2 samples/ second, 4 samples/second, 8 sa mples/second, 16 samples/sec ond, 32 samples/second, 64 samples/second, and 120 samples/ second). in the auto-sleep mode, if no change in the orientation, shake or tap has occurred and the sleep counter has elapsed, the device will go into the auto-wake mode. when the device is in the auto-sleep mode, the mode (0x07) register, bit ase is high. the device can be programmed to continually cycle between auto-wake/sleep. note: the device can either be powered on in wake/sleep state depending on ase/awe settings. if the awe bit is set, the device is powered on in, in sleep state. if the as w bit is set, the device is powered on in, in wake state. table 8. auto-wake/sleep truth table trigger wake-up reset sleep counter trigger sleep mode orientation detection change yes yes no shake yes yes no delta g (set with pd (0x0a) and pdet (0x09)) yes (xda = yda = zda = 0) yes no pulse detect (120 samples/second) yes yes no sleep counter elapsed no no yes
sensors freescale semiconductor, inc. 14 mma7660fc register definitions note: to write to the registers the mode bit in the mode (0x07) register must be set to 0, placing the device in standby mode. $00: 6-bits output value x (read only when not in test mode) xout ? x output signed byte 6-bit 2?s complement data with allowable range of +31 to -32. xout[5] is 0 if the g direction is posi tive, 1 if the g direction is negative. if the alert bit is set, the register was read at the same time as the device was attempting to update the contents. the regist er must be read again. $01: 6-bits output value y (read only when not in test mode) yout ? y output signed byte 6-bit 2?s complement data with allowable range of +31 to -32. yout[5] is 0 if the g direction is posi tive, 1 if the g direction is negative. if the alert bit is set, the register was read at the same time as the device was attempting to update the contents. the regist er must be read again. $02: 6-bits output value z (rea d only when not in test mode) zout ? z output signed byte 6-bit 2?s complement data with allowable range of +31 to -32. zout[5] is 0 if the g direction is posit ive, 1 if the g direction is negative. if the alert bit is set, the register was read at the same time as the device was attempting to update the contents. the regist er must be read again. table 9. user register summary address name definition bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 $00 xout 6-bit output value x - alert xout[5] xout[4] xout[3] xout[2] xout[1] xout[0] $01 yout 6-bit output value y - alert yout[5] yout[4] yout[3] yout[2] yout[1] yout[0] $02 zout 6-bit output value z - alert zout[5] zout[4] zout[3] zout[2] zout[1] zout[0] $03 tilt tilt status shake alert tap pola[2] pola[1] pola[0] bafro[1] bafro[0] $04 srst sampling rate status 0 0 0 0 0 0 awsrs amsrs $05 spcnt sleep count sc[7] sc[6] sc[5] sc[4] sc[3] sc[2] sc[1] sc[0] $06 intsu interrupt setup shintx shinty shintz gint asint pdint plint fbint $07 mode mode iah ipp scps ase awe ton - mode $08 sr auto-wake/sleep and portrait/landscape samples per seconds and debounce filter filt[2] filt[1] filt[0] awsr[1] awsr[0] amsr[2] amsr[1] amsr[0] $09 pdet tap detection zda yda xda pdth[4] pdth[3] pdth[2] pdth[1] pdth[0] $0a pd tap debounce count pd[7] pd[6] pd[5] pd[4] pd[3] pd[2] pd[1] pd[0] $0b-$1f factory reserved - - - - - - - - d7 d6 d5 d4 d3 d2 d1 d0 - alert xout[5] xout[4] xout[3] xout[2] xout[1] xout[0] 00000000 d7 d6 d5 d4 d3 d2 d1 d0 - alert yout[5] yout[4] yout[3] yout[2] yout[1] yout[0] 00000000 d7 d6 d5 d4 d3 d2 d1 d0 - alert zout[5] zxout[4] zout[3] zout[2] zout[1] zout[0] 000 0 0000
sensors 15 freescale semiconductor, inc. mma7660fc $03: tilt status (read only) tilt bafro[1:0] 00:unknown condition of front or back 01: front: equipment is lying on its front 10: back: equipment is lying on its back pola[2:0] 000: unknown condition of up or down or left or right 001: left: equipment is in landscape mode to the left 010: right: equipment is in landscape mode to the right 101: down: equipment standing vertically in inverted orientation 110: up: equipment standing vertically in normal orientation tap 1: equipment has detected a tap 0: equipment has not detected a tap alert 0: register data is valid 1: the register was read at the same time as mma7660fc was attempting to update the contents. re-read the register shake 0: equipment is not experiencing shake in one or more of the axes enabled by shintx, shinty, and shintz 1: equipment is experiencing shake in one or more of the axes enabled by shintx, shinty, and shintz note: when entering active mode from standby mo de, if the device is flat (1g on z-axis) the value for bafro will be back (-1g) or front (+1g) but pola will be in unknown condition. if the device is being held in an up/down/right/left position, the pola v alue will be updated with current orientation, bu t bafro will be in unknown condition. $04: sample rate status register (read only) srst amsrs 0: samples per second specified in amsr[2:0] is not active 1: samples per second specified in amsr[2:0] is active awsrs 0: samples per second specified in awsr[1:0] is not active 1: samples per second specified in awsr[1:0] is active $05: sleep count register (read/write) spcnt writing to the spcnt (0x05) register resets the internal sleep counter. sc[7:0] sets the 8-bit maximum count value for the 8-bit internal sleep counter in auto-sleep. when th e 8-bit internal sleep counter reaches the value set by sc[7:0], mma7660fc will exit auto-sleep and switch to the samples per second specified in awsr[1:0] of the sr (0x08) register. d7 d6 d5 d4 d3 d2 d1 d0 shake alert tap pola[2] pola[1] pola[0] bafro[1] bafro[0] 0000000 0 d7 d6 d5 d4 d3 d2 d1 d0 000000a w s r sa m s r s 00000000 d7 d6 d5 d4 d3 d2 d1 d0 s c [ 7 ]s c [ 6 ]s c [ 5 ]s c [ 4 ]s c [ 3 ]s c [ 2 ]s c [ 1 ]s c [ 0 ] 00000000
sensors freescale semiconductor, inc. 16 mma7660fc $06: interrupt setup register intsu fbint 0: front/back position change does not cause an interrupt 1: front/back position change causes an interrupt plint 0: up/down/right/left position change does not cause an interrupt 1: up/down/right/left position change causes an interrupt pdint 0: successful tap detection does not cause an interrupt 1: successful tap detection causes an interrupt asint 0: exiting auto-sleep does not cause an interrupt 1: exiting auto-sleep causes an interrupt gint 0: there is not an automat ic interrupt after every measurement 1: there is an automatic inte rrupt after every measurement, when g-cell readings are updated in xout, yout, zout registers, regardless of whet her the readings have changed or not. this interrupt does not affect the auto-sleep or auto- wake functions. shintx 0: shake on the x-axis does not cause an interrupt or set the shake bit in the tilt register 1: shake detected on the x-axis causes an interrupt, and sets the shake bit in the tilt register shinty 0: shake on the y-axis does not cause an interrupt or set the shake bit in the tilt register 1: shake detected on the y-axis causes an interrupt, and sets the shake bit in the tilt register shintz 0: shake on the z-axis does no t cause an interrupt or set the shake bit in the tilt register 1: shake detected on the z-axis causes an interrupt, and sets the shake bit in the tilt register. the active interrupt condition (irq = 0 if iah = 0, irq = 1 if iah = 1) is released during the acknowledge bit of the slave address transmission of the first subsequent i 2 c to mma7660fc after the interrupt was asserted. d7 d6 d5 d4 d3 d2 d1 d0 shintx shinty shintz gint asint pdint plint fbint 00000000
sensors 17 freescale semiconductor, inc. mma7660fc $07: mode register (read/write) mode note: writing to the mode register resets sleep timing, and clears the xout, yout, zout , tilt registers.reading to the mode register resets sleep timing. note: the device must be placed in standby mode to change the value of the registers. note: the device can only enter into test mode, when the previous mode was standby mode. if the device was in active mode, set mma766fc to standby mode (mode = ton = 0), then enter test mode (mode = 0, ton = 1). mode 0: standby mode or test mode depending on state of ton 1: active mode existing state of ton bit must be 0, to write mode = 1. test mode must not be enabled. mma7660fc always enters active mode using the samples per second specified in amsr[2:0] of the sr (0x08) register. when mma7660fc enters active mode with [ase:awe] = 11, mma7660fc operates auto-sleep functionality first. ton 0: standby mode or active mode depending on state of mode 1: test mode existing state of mode bit mu st be 0, to write ton = 1. device must be in standby mode. in test mode (ton = 1), the data in the xout, yout and zout registers is not updated by measurement, but is instead updated by the user through the i 2 c interface for test purposes. changes to the xout, yout and zout register data is processed by mma7660fc to change orientation status and generate interrupts just like active mode. debounce filtering and shake detection are disabled in test mode. awe 0: auto-wake is disabled 1: auto-wake is enabled. when auto-wake functionality is operating, the awsrs bit is the srst register is set and the device uses the samples per second specified in awsr[1:0] of the sr (0x08) register. when mma7660fc automatically exits auto-wake by a selected interrupt, the device wi ll then switch to the samples per second specified in amsr[2:0] of the sr (0x08) register. if ase = 1, then auto-sleep functionality is now enabled ( ta b l e 11 ). ase 0: auto-sleep is disabled 1: auto-sleep is enabled when auto-sleep functionality is operating, the amsrs bit is the srst register is set and the device uses the samples per second specified in amsr[2:0] of the sr (0x08) register. when mma7660fc automatically exits auto-sleep because the sleep counter times out, th e device will then switch to the samples per second specifie d in awsr[1:0] of the sr register. if awe = 1, then auto-wake functionality is now enabled ( table 11 ). scps 0: the prescaler is divide-by-1. the 8-bit internal sleep counter input clock is the samples per second set by amsr[2:0], so the clock range is 120 hz to 1 hz depending on amsr[2:0] setting. sle ep counter timeout range is 256 times the prescaled clock (see ta b l e 1 2 ). 1: prescaler is divide-by-16. the 8-bit sleep counter input clock is the samples per second set by amsr[2:0] divided by 16, so the clock range is 4 hz to 0.0625 hz depending on amsr[2:0] setting. sleep counter timeout range is 256 times the prescaled clock (see ta b l e 1 2 ). ipp 0: interrupt output int is open-drain. 1: interrupt output int is push-pull note: do not connect pull-up resistor from int to higher voltage than dvdd. iah 0: interrupt output int is active low 1: interrupt output int is active high the active interrupt condition (irq = 0 if iah = 0, irq = 1 if iah = 1) is released during the acknowledge bit of the slave address transmission of the first subsequent i 2 c to the device after the interrupt was asserted. d7 d6 d5 d4 d3 d2 d1 d0 iah ipp scps ase awe ton - mode 00000000 table 10. modes mode of operation d0 - mode d2 - ton standby mode 0 0 test mode 0 1 active mode 1 0
sensors freescale semiconductor, inc. 18 mma7660fc note: if interrupts are enabled, interrupts will behav e normally in all conditions stated in table 11 . table 12. sleep counter timeout ranges $08: auto-wake and active mode portrait/landsca pe samples per seconds register (read/write) sr ? sample rate register table 11. ase/awe conditions condition auto-wake (sleep mode) auto-sleep (run mode) awe = 0, ase = 0 x awe = 1, ase = 0 x awe = 0, ase = 1 x x awe = 1, ase = 1 x x amsr scps = 0 scps = 1 minimum range (2 0 ) maximum range (2 8 ) minimum range (2 0 ) maximum range (2 8 ) 1 sps 1 s 256 s 16 s 4096 s 2 sps 0.5 s 128 s 8 s 2048 s 4 sps 0.25 s 34 s 4 s 1024 s 8 sps 0.125 s 32 s 2 s 512 s 16 sps 0.625 s 16 s 1 s 256 s 32 sps 0.03125 s 8 s 0.5 s 128 s 64 sps 0.0156 s 4 s 0.25 s 64 s 120 sps 0.00836 s 2.14 s 0.133 s 34.24 s d7 d6 d5 d4 d3 d2 d1 d0 filt[2] filt[1] filt[0] awsr[1] awsr[0] amsr[2] amsr[1] amsr[0] 000 0 0 0 0 0
sensors 19 freescale semiconductor, inc. mma7660fc amsr[2:0] name description 000 ampd tap detection mode and 120 samples/second active and auto-sleep mode tap detection sampling rate : the device takes readings continually at a rate of nominally 3846 g-cell measurements a second. it then filters t hese high speed measurements by mainta ining continuous rolling averages of the current and last g-cell measurements. the averages ar e updated every 260 s to track fast moving accelerations. tap detection: itself compares the two filtered axis re sponses (fast and slow) descri bed above for each axis. the absolute (unsigned) difference between the fast and slow axis responses is compared against the tap detection delta threshold value pdth[4:0] in the pdet (0x09) register. for portrait/landscape detection: the device takes and averages 32 g-cell measurements every 8.36 ms in active mode and auto-sleep. the update rate is 120 samples per second. these measurements update the xout (0x00), yout (0x01), and zout (0x02) registers also. 001 am64 64 samples/second active and auto-sleep mode for portrait/landscape detection : the device takes and averages 32 g-cell measurements every 15.625 ms in active mode and auto-sleep. the update rate is 64 samples per second. these measurements update the xout (0x00), yout (0x01), a nd zout (0x02) registers also. 010 am32 32 samples/second active and auto-sleep mode for portrait/landscape detection: the device takes and averages 32 g-cell me asurements every 31.25 ms in active mode and auto-sleep. the update rate is 32 samples per second. these measurements update xout (0x00), yout (0x01), and zout (0x02) registers also. 011 am16 16 samples/second active and auto-sleep mode for portrait/landscape detection: the device takes and averages 32 g-cell measurements every 62.5 ms in active mode and auto-sleep. the update rate is 16 samples per second. these measurements update the xout (0x00), yout (0x01), and zout (0x02) registers also. 100 am8 8 samples/second active and auto-sleep mode for portrait/landscape detection: the device takes and averages 32 g-cell measurements every 125 ms in active mode and auto-sleep. the update rate is 8 samples per second. these measurements update the xout (0x00), yout (0x01), and zout (0x02) registers also. 101 am4 4 samples/second active and auto-sleep mode for portrait/landscape detection: the device takes and averages 32 g-cell measurements every 250 ms in active mode and auto-sleep. the update rate is 4 samples per second. these measurements update the xout (0x00), yout (0x01), and zout (0x02) registers also. 110 am2 2 samples/second active and auto-sleep mode for portrait/landscape detection: the device takes and averages 32 g-cell measurements every 500 ms in active mode and auto-sleep. the update rate is 2 samples per second. these measurements update the xout (0x00), yout (0x01), and zout (0x02) registers also. 111 am1 1 sample/second active and auto-sleep mode for portrait/landscape detection: the device takes and averages 32 g-cell measurements every 1000 ms in active mode and auto-sleep. the update rate is 1 sample per se cond. these measurements updat e the xout (0x00), yout (0x01), and zout (0x02) registers also.
sensors freescale semiconductor, inc. 20 mma7660fc awsr[1:0] name description 00 aw32 32 samples/second auto-wake mode for portrait/landscape detection: the device takes and averages 32 g-cell measurements every 31.25 ms in auto-wake. the update rate is 32 samples per second. these measurements update the xout (0x00), yout (0x01), and zout (0x02) registers also. 01 aw16 16 samples/second auto-wake mode for portrait/landscape detection : the device takes and averages 32 g-cell measurements every 62.5 ms in auto-wake. the update rate is 16 samples per second. these measurements update the xout (0x00), yout (0x01), and zout (0x02) registers also. 10 aw8 8 samples/second auto-wake mode for portrait/landscape detection: the device takes and averages 32 g-cell measurements every 125 ms in auto-wake. the update rate is 8 samples per second. these measurements update the xout (0x00), yout (0x01), and zout (0x02) registers also. 11 aw1 1 sample/second auto-wake mode for portrait/landscape detection : the device takes and averages 32 g- cell measurements every 1000 ms in auto-wake. the update rate is 1 sample per sec ond. these measurements update the xout (0x00), yout (0x01), and zout (0x02) registers also. filt[2:0] description 000 tilt debounce filtering is disabled. t he device updates portrait/landscape every readi ng at the rate set by amsr[2:0] or awsr[1:0] 001 2 measurement samples at the rate set by amsr[2:0] or awsr[1:0] have to match before the device updates portrait/ landscape data in tilt (0x03) register. 010 3 measurement samples at the rate set by amsr[2:0] or awsr[1:0] have to match before the device updates portrait/ landscape data in tilt (0x03) register. 011 4 measurement samples at the rate set by amsr[2:0] or awsr[1:0] have to match before the device updates portrait/ landscape data in tilt (0x03) register. 100 5 measurement samples at the rate set by amsr[2:0] or awsr[1:0] have to match before the device updates portrait/ landscape data in tilt (0x03) register. 101 6 measurement samples at the rate set by amsr[2:0] or awsr[1:0] have to match before the device updates portrait/ landscape data in tilt (0x03) register. 110 7 measurement samples at the rate set by amsr[2:0] or awsr[1:0] have to match before the device updates portrait/ landscape data in tilt (0x03) register. 111 8 measurement samples at the rate set by amsr[2:0] or awsr[1:0] have to match before the device updates portrait/ landscape data in tilt (0x03) register.
sensors 21 freescale semiconductor, inc. mma7660fc $09: tap/pulse detectio n register (read/write) pdet note: if xda = yda = zda = 0, samples per second is 120 samp les/second, and auto-wake/ sleep feature is enabled, the tap interrupt will reset the sleep counter. xda 1: x-axis is disabled for tap detection 0: x-axis is enabled for tap detection yda 1: y-axis is disabled for tap detection 0: y-axis is enabled for tap detection zda 1: z-axis is disabled for tap detection 0: z-axis is enabled for tap detection $0a: pd: tap/pulse debounce count register (read/write) d7 d6 d5 d4 d3 d2 d1 d0 zda yda xda pdth[4] pdth[3] pdth[2] pdth[1] pdth[0] 00000000 pdth[4:0] description 00000 tap detection threshold is 1 count 00001 00010 tap detection threshold is 2 counts 00011 tap detection threshold is 3 counts ... ... and so on up to... 11101 tap detection threshold is 29 counts 11110 tap detection threshold is 30 counts 11111 tap detection threshold is 31 counts d7 d6 d5 d4 d3 d2 d1 d0 pd[7] pd[6] pd[5] pd[4] pd[3] pd[2] pd[1] pd[0] 00000000 pd[4:0] description 00000000 the tap detection debounce filtering requires 2 adjacent tap det ection tests to be the same to trigger a tap event and set the tap bit in the tilt (0x03) register, and optionally set an interrupt if pdint is set in the intsu (0x06) register. tap detectio n response time is nominally 0.52 ms. 00000001 00000010 tap detection debounce filtering requires 3 adjacent tap detection tests to be the same to trigger a tap event and set the tap bit in the tilt (0x03) register, and optionally set an interrupt if pdint is set in the intsu (0x06) register. tap detection response time is nominally 0.78 ms. 00000011 tap detection debounce filtering requires 4 adjacent tap detection tests to be the same to trigger a tap event and set the tap bit in the tilt (0x03) register, and optionally set an interrupt if pdint is set in the intsu (0x06) register. tap detection response time is nominally 1.04 ms. ... ... and so on up to... 11111101 tap detection debounce filtering requires 254 adjacent tap detec tion tests to be the same to trigger a tap event and se t the tap bit in the tilt (0x03) register, and optionally set an interrupt if pdint is set in the intsu (0x06) register. tap detectio n response time is nominally 66.04 ms. 11111110 tap detection debounce filtering requires 255 adjacent tap detec tion tests to be the same to trigger a tap event and se t the tap bit in the tilt (0x03) register, and optionally set an interrupt if pdint is set in the intsu (0x06) register. tap detectio n response time is nominally 66.3 ms. 11111111 tap detection debounce filtering requires 256 adjacent tap detec tion tests to be the same to trigger a tap event and se t the tap bit in the tilt (0x03) register, and optionally set an interrupt if pdint is set in the intsu (0x06) register. tap detectio n response time is nominally 66.56 ms.
sensors freescale semiconductor, inc. 22 mma7660fc serial interface serial-addressing mma7660fc operates as a slave that sends and receives data through an i 2 c 2-wire interface. the interface uses a serial data line (sda) and a serial clock line (scl) to achieve bi-directional communication between master(s) and slave(s). a master (typically a microcontroller) initiates all data transfe rs to and from the device, and generates the scl clock that synchronizes the data transfer. figure 7. 2-wire serial interface timing details the device?s sda line operates as both an input and an open-drain output. a pull-up resistor, typically 4.7 k , is required on sda. the device?s scl line operates only as an input. a pull-up resistor, typically 4.7 k , is required on scl if there are multiple masters on the 2-wire interface, or if the master in a single-master system has an open-drain scl output. each transmission consists of a start condition ( figure 7 ) sent by a master, followed by mma7660fc's 7-bit slave address plus r/w bit, a register address byte, one or more data bytes, and finally a stop condition. figure 8. start and stop conditions start and stop conditions both scl and sda remain high when the interface is not bus y. a master signals the beginning of a transmission with a start (s) condition by transitioning sda from high to low while scl is high. when the master has finished communicating with the slave, it issues a stop (p) condition by transitioning sda fr om low to high while scl is high. the bus is then free for ano ther transmission. bit transfer one data bit is transferred during each clock tap. see figure 9 . the data on sda must remain stable while scl is high. figure 9. bit transfer scl sda t low t high t f t r t hd sta t hd dat t hd sta t su dat t su sta t buf t su sto start condit ion stop condit ion repeated start condit ion start condit ion data line stable data valid change of data allowed sda scl start condition sda scl stop condition p s
sensors 23 freescale semiconductor, inc. mma7660fc acknowledge the acknowledge bit is a clocked 9th bit, shown in figure 10 , which the recipient uses to handshake a receipt of each byte of data. thus each byte transferred effectively requires 9-bits. the master generates the 9 th clock tap, and the recipient pulls down sda during the acknowledge clock tap, such that the sda line is stable low during the high period of the clock tap. when the master is transmitting to mma7660fc, it generates the acknowledge bit because it is the recipient. when the device is transmitting to the master, the master generates the ac knowledge bit because the master is the recipient. figure 10. acknowledge the slave address mma7660fc has a 7-bit long slave address, shown in figure 11 . the bit following the 7-bit slave address (bit eight) is the r/w bit, which is low for a write command and high fo r a read command. the device has a factory set i 2 c slave address which is normally 1001100 (0x4c). contact the factory to request a different i 2 c slave address, which is available in the range 0001000 to 1110111 (0x08 to 0xef), by metal mask option. figure 11. slave address the device monitors the bus continuously, waiting for a star t condition followed by its slave address. when the device recognizes its slave address, it acknowledges an d is then ready for continued communication. message format for writing mma7660fc a write to mma7660fc comprises t he transmission of the device?s ke yscan slave address with the r/w bit set to 0, followed by at least one byte of information. the fi rst byte of information is the register ad dress of the first internal register that is to be updated. the master write address is 1001 1000 (0x98). if a stop condition is detected after ju st the register address is received, then mma7660fc takes no action. see figure 12 . mma7660fc clears its internal register address pointer to register 0x00 when a stop condition is detected, so a single byte write has no net effect because the register address given in this fir st and only byte is replaced by 0x00 at the stop co ndition. the internal register address pointer is not , however, cleared on a repeated start condition. use a single byte write followed by a repeated start to read back data from a register. any bytes received after the register address are data bytes. the first data byte goes into the internal register of the device selected by the register address. see figure 12 . figure 12. single byte write master st device address [6:0] w register address [6:0] data [7:0] sp slave ak ak ak start condition sda by transmitter s 12 89 clock pulse for acknowledgement sda by receiver scl clock tap for sda 1 r/w ack msb scl 01 0100
sensors freescale semiconductor, inc. 24 mma7660fc if multiple data bytes are transmitted before a stop condition is detected, these bytes are ge nerally stored in subsequent mma7660fc internal registers because the r egister address generally auto-increments. figure 13. multip le bytes write message format for reading mma7660fc mma7660fc is read using it?s internally stored register address as address pointer, the same way the stored register address is used as address pointer for a write. the pointer generally auto-increments after each data byte is read using the same rules as for a write. thus, a read is initia ted by first configuring the device?s register address by performing a write ( figure 12 ) followed by a repeated start. the master write address is 1001 1001 (0x9 9). the master can now read 'n' consecutive bytes from it, with the first data byte being read from the register addressed by the initialized register address. figure 14. single byte read figure 15. multiple bytes read master st device address [6:0] w register address [6:0] data [7:0] data [7:0] sp slave ak ak ak ak master st device address [6:0] w register address [6:0] sr device address [6:0] r nak sp slave ak ak ak data [7:0] master st device address [6:0] w register address [6:0] sr device address [6:0] r ak slave ak ak ak data [7:0] master ak ak nak sp slave data [7:0] data [7:0] data [7:0]
sensors 25 freescale semiconductor, inc. mma7660fc appendix a ? package requirements for mma7660fc minimum recommended footprint for surface mounted applications surface mount board layout is a critical portion of the total design. the footprint for the surface mount packages must be the correct size to ensure proper solder connection interface between the board and the package. with the correct footprint, the packages will self-align when subjected to a solder reflow proc ess. it is always recommended to design boards with a solder mask layer to avoid bridging and shorting between solder pads. soldering and mounting guidelines for the dfn accelerometer sensor to a pc board these guidelines are for soldering and mounting the dual flat no-lead (dfn) package inertial sensors to printed circuit boards (pcbs). the purpose is to minimize the stress on the package after board mounting. the mma7660 digital output accelerometer uses the dfn package platform. this section descr ibes suggested methods of soldering these devices to the pc board for consumer applications. pages 31, 32, and 33 show the package outline drawing for the package. overview of soldering considerations information provided here is based on experiments executed on dfn devices. they do not represent exact conditions present at a customer site. hence, information herein should be us ed as guidance only and proce ss and design optimizations are recommended to develop an application specific solution. it s hould be noted that with the proper pcb footprint and solder stenc il designs the package will self-align during the solder reflow process. the following are the recommended guidelines to follow fo r mounting dfn sensors for consumer applications. halogen content this package is designed to be halogen free, exceeding most industry and customer standards. halogen free means that no homogeneous material within the assembly package shall cont ain chlorine (cl) in excess of 700 ppm or 0.07% weight/weight or bromine (br) in excess of 900 ppm or 0.09% weight/weight. note: halogen free is only compliant to the mma7660fc, not to the packaging material. pcb mounting recommendations 1. the pcb land should be designed with non solder mask defined (nsmd) as shown in figure 16 and figure 17 . 2. no additional via pattern underneath package. 3. pcb land pad is 0.825 mm x 0.3 mm as shown in figure 16 and figure 17 . 4. do not solder down smaller side tabs on either end of the package. 5. the solder mask opening is equal to the size of the pcb land pad plus 0.15 mm. 6. the stencil aperture size is equal to the pcb land pad ? minus 0.03 mm total. 7. stencil thickness should be 75 m. 8. do not place any components or vias at a distance less than 2 mm from the package land ar ea. this may cause additional package stress if it is too close to the package land area. 9. signal traces connected to pads should be as symmetric as possible. put dummy traces on nc pads in order to have same length of exposed trace for all pads. signal traces with 0.15 mm width and minimum 0.5 mm length for all pcb land pads near the package are recommended as shown in figure 16 and figure 17 . wider trace can be cont inued after the 0.5 mm zone. 10. use a standard pick and place process and equipment. do not use a hand soldering process. 11. it is recommended to use a no clean solder paste. 12. do not use a screw down or stacking to fix the pcb into an enclosure because this could bend the pcb putting stress on the package. 13. the pcb should be rated for the multiple lead-f ree reflow condition with max 260c temperature. 14. no copper traces on top layer of pcb under the pack age. this will cause planarity issues with board mount. freescale dfn sensors are compliant with restrictions on hazardous substances (rohs), having halide free molding compound (green) and lead-free terminations. these terminations are compatible with tin-lead (sn-pb) as well as tin-silver- copper (sn-ag-cu) solder paste soldering processes. reflow prof iles applicable to those processes can be used successfully for soldering the devices.
sensors freescale semiconductor, inc. 26 mma7660fc figure 16. package footprint, pcb land pattern, and stencil design figure 17. pcb land pattern detail
sensors 27 freescale semiconductor, inc. mma7660fc appendix b - sensing direction figure 18. product orientation on perpendicular axis figure 19. product orientations showing direction for each axis in composite direction of earth?s gravity top view xout @ -1g yout @ 0g zout @ 0g xout @ 0g yout @ -1g zout @ 0g xout @ +1g yout @ 0g zout @ 0g xout @ 0g yout @ +1g zout @ 0g xout @ 0g yout @ 0g zout @ +1g xout @ 0g yout @ 0g zout @ -1g side view -z +x -y +y +z -x -y +z -x +y -z +x
sensors freescale semiconductor, inc. 28 mma7660fc appendix c - mma7660fc acquisition code table 6-bit result binary 2's comp g value angle x or y angle z 0 0 0 0.000g 0.00 90.00 1 1 1 0.047g 2.69 87.31 2 10 2 0.094g 5.38 84.62 3 11 3 0.141g 8.08 81.92 4 100 4 0.188g 10.81 79.19 5 101 5 0.234g 13.55 z-axis must be in the range 76.45 6 110 6 0.281g 16.33 73.67 7 111 7 0.328g 19.16 70.84 8 1000 8 0.375g 22.02 67.98 9 1001 9 0.422g 24.95 65.05 10 1010 10 0.469g 27.95 62.05 11 1011 11 0.516g 31.04 58.96 12 1100 12 0.563g 34.23 55.77 13 1101 13 0.609g 37.54 52.46 14 1110 14 0.656g 41.01 48.99 15 1111 15 0.703g 44.68 45.32 16 10000 16 0.750g 48.59 41.41 17 10001 17 0.797g 52.83 37.17 18 10010 18 0.844g 57.54 32.46 19 10011 19 0.891g 62.95 27.05 20 10100 20 0.938g 69.64 20.36 21 10101 21 0.984g 79.86 10.14 22 10110 22 1.031g 23 10111 23 1.078g 24 11000 24 1.125g 25 11001 25 1.172g 26 11010 26 1.219g 27 11011 27 1.266g 28 11100 28 1.313g shaken 29 11101 29 1.359g shaken 30 11110 30 1.406g shaken 31 11111 31 1.453g shaken 63 111111 -1 -0.047g -2.69 -87.31 62 111110 -2 -0.094g -5.38 -84.62 61 111101 -3 -0.141g -8.08 -81.92 60 111100 -4 -0.188g -10.81 -79.19 59 111011 -5 -0.234g -13.55 -76.45 58 111010 -6 -0.281g -16.33 -73.67 57 111001 -7 -0.328g -19.16 -70.84 56 111000 -8 -0.375g -22.02 -67.98 55 110111 -9 -0.422g -24.95 -65.05 54 110110 -10 -0.469g -27.95 -62.05 53 110101 -11 -0.516g -31.04 -58.96 52 110100 -12 -0.563g -34.23 -55.77 51 110011 -13 -0.609g -37.54 -52.46 50 110010 -14 -0.656g -41.01 -48.99
sensors 29 freescale semiconductor, inc. mma7660fc appendix c - mma7660fc acquisition code table , continued 49 110001 -15 -0.703g -44.68 -45.32 48 110000 -16 -0.750g -48.59 -41.41 47 101111 -17 -0.797g -52.83 -37.17 46 101110 -18 -0.844g -57.54 -32.46 45 101101 -19 -0.891g -62.95 -27.05 44 101100 -20 -0.938g -69.64 -20.36 43 101011 -21 -0.984g -79.86 -10.14 42 101010 -22 -1.031g 41 101001 -23 -1.078g 40 101000 -24 -1.125g 39 100111 -25 -1.172g 38 100110 -26 -1.219g 37 100101 -27 -1.266g 36 100100 -28 -1.313g shaken 35 100011 -29 -1.359g shaken 34 100010 -30 -1.406g shaken 33 100001 -31 -1.453g shaken 32 100000 -32 -1.500g shaken
sensors freescale semiconductor, inc. 30 mma7660fc appendix d - i 2 c ac characteristics this section includes information about i 2 c ac characteristics. table 1. i 2 c ac characteristics (typical operating circuit, v dd = 1.71 v to 2.75 v, t a = t min to t max , unless otherwise noted. typical current values are at v dd = 1.8 v, t a = +25c.) parameter symbol min typ max units serial clock frequency (1) 1. parameters tested 100% at final test at room temperature; li mits at -40c and +85c, verified by characterization, not test i n production. f scl 400 khz bus free time between a stop and a start condition (2) 2. limits verified by characteri zation, not tested in production. t buf 1.3 s hold time, (repeated) start condition (2) t hd, sta 0.6 s repeated start condition setup time (2) t su, sta 0.6 s stop condition setup time (2) t su, sto 0.6 s data hold time (2) t hd, dat 0.9 s data setup time (2) t su, dat 100 ns scl clock low period (2) t low 1.3 s scl clock high period (2) t high 0.7 s rise time of both sda and scl signals, receiving (2) t r 20+0.1c b 300 ns fall time of both sda and scl signals, receiving (2) t f 20+0.1c b 300 ns fall time of sda transmitting (2) t f.tx 20+0.1c b 250 ns pulse width of spike suppressed (2) t sp 25 ns capacitive load for each bus line (2) c b 400 pf
sensors 31 freescale semiconductor, inc. mma7660fc package dimensions
sensors freescale semiconductor, inc. 32 mma7660fc package dimensions
sensors 33 freescale semiconductor, inc. mma7660fc package dimensions
sensors freescale semiconductor, inc. 34 mma7660fc table 2. revision history revision number revision date description of changes 9 03/2012 ? changed pin 10 from n/c to reserved on page 1, figure 1, figure 2 and table 1: pin description.
mma7660fc rev. 8 03/2012 information in this document is provided solely to enable system and software implementers to use freescale semiconduc tor products. there are no express or implied copyright licenses granted hereunder to design or fabricate any integrated circuits or integrated circuits based on the information in this document. freescale semiconductor reserves the right to make changes without further notice to any products herein. freescale semiconductor makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does freescale semiconductor assume any liability ar ising out of the application or use of any product or circuit, and specifically discl aims any and all liability, including without limitation consequential or incidental damages. ?typical? parameters that may be provided in freescale semiconductor data s heets and/or specifications can and do vary in different applications and actual performance may vary over time. all operating parameters, including ?typicals?, must be validated for each customer application by customer?s technical experts. freescale se miconductor does not convey any license under its patent rights nor the rights of others. freescale semiconductor products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the fa ilure of the freescale semiconductor product could create a situation where personal injury or death may occur. should buyer purchase or use freescale semiconductor products for any such unintended or unauthorized application, buyer shall indemni fy and hold freescale semiconductor and its officers, employees, subsidiaries, affili ates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that freescale semiconductor was negligent regarding the design or manufacture of the part. freescale and the freescale logo are trademarks of freescale semiconductor, inc., reg. u.s. pat. & tm. off. xtrinsic is a trademark of freescale semiconductor, inc. all other product or service names are the property of their respective owners. ? 2012 freescale semiconductor, inc. all rights reserved. rohs-compliant and/or pb-free versions of freesc ale products have the functi onality and electrical characteristics of their non-rohs-compliant and/or non-pb-free counterparts. for further information, see http:/www.freescale.com or contact your freescale sales representative. for information on freescale?s environmental products program, go to http://www.freescale.com/epp. how to reach us: home page: www.freescale.com web support: http://www.freescale.com/support usa/europe or locations not listed: freescale semiconductor, inc. technical information center, el516 2100 east elliot road tempe, arizona 85284 1-800-521-6274 or +1-480-768-2130 www.freescale.com/support europe, middle east, and africa: freescale halbleiter deutschland gmbh technical information center schatzbogen 7 81829 muenchen, germany +44 1296 380 456 (english) +46 8 52200080 (english) +49 89 92103 559 (german) +33 1 69 35 48 48 (french) www.freescale.com/support japan: freescale semiconductor japan ltd. headquarters arco tower 15f 1-8-1, shimo-meguro, meguro-ku, tokyo 153-0064 japan 0120 191014 or +81 3 5437 9125 support.japan@freescale.com asia/pacific: freescale semiconductor china ltd. exchange building 23f no. 118 jianguo road chaoyang district beijing 100022 china +86 010 5879 8000 support.asia@freescale.com for literature requests only: freescale semiconductor lite rature distribution center 1-800-441-2447 or +1-303-675-2140 fax: +1-303-675-2150 ldcforfreescalesemiconductor@hibbertgroup.com

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