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d a t a sh eet product speci?cation file under integrated circuits, ic06 december 1990 integrated circuits 74hc/hct7030 9-bit x 64-word fifo register; 3-state for a complete data sheet, please also download: the ic06 74hc/hct/hcu/hcmos logic family specifications the ic06 74hc/hct/hcu/hcmos logic package information the ic06 74hc/hct/hcu/hcmos logic package outlines
december 1990 2 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 features synchronous or asynchronous operation 3-state outputs master-reset input to clear control functions 33 mhz (typ.) shift-in, shift-out rates with or without flags very low power consumption cascadable to 25 mhz (typ.) readily expandable in word and bit dimensions pinning arranged for easy board layout: input pins directly opposite output pins output capability: standard i cc category: lsi general description the 74hc/hct7030 are high-speed si-gate cmos devices specified in compliance with jedec standard no. 7a. the 74hc/hct7030 is an expandable, first-in first-out (fifo) memory organized as 64 words by 9 bits. a 33 mhz data-rate makes it ideal for high-speed applications. even at high frequencies, the i cc dynamic is very low (f max = 18 mhz; v cc = 5 v produces a dynamic i cc of 80 ma). if the device is not continuously operating at f max , then i cc will decrease proportionally. with separate controls for shift-in (si) and shift-out ( so), reading and writing operations are completely independent, allowing synchronous and asynchronous data transfers. additional controls include a master-reset input ( mr) and an output enable input ( oe). flags for data-in-ready (dir) and data-out-ready (dor) indicate the status of the device. devices can be interconnected easily to expand word and bit dimensions. all output pins are directly opposite the corresponding input pins thus simplifying board layout in expanded applications. inputs and outputs data inputs (d 0 to d 8 ) as there is no weighting of the inputs, any input can be assigned as the msb. the size of the fifo memory can be reduced from the 9 64 configuration, i.e. 8 64, 7 64, down to 1 64, by tying unused data input pins to v cc or gnd. data outputs (q 0 to q 8 ) as there is no weighting of the outputs, any output can be assigned as the msb. the size of the fifo memory can be reduced from the 9 64 configuration as described for data inputs. in a reduced format, the unused data output pins must be left open circuit. master-reset ( mr) when mr is low, the control functions within the fifo are cleared, and data content is declared invalid. the data-in-ready (dir) flag is set high and the data-out-ready (dor) flag is set low. the output stage remains in the state of the last word that was shifted out, or in the random state existing at power-up. status flag outputs (dir, dor) indication of the status of the fifo is given by two status flags, data-in-ready (dir) and data-out-ready (dor): shift-in control (si) data is loaded into the input stage on a low-to-high transition of si. a high-to-low transition triggers an automatic data transfer process (ripple through). if si is held high during reset, data will be loaded at the rising edge of the mr signal. shift-out control ( so) a low-to-high transition of so causes the dor flags to go low. a high-to-low transition of so causes upstream data to move into the output stage, and empty locations to move towards the input stage (bubble-up). output enable ( oe) the outputs q 0 to q 8 are enabled when oe = low. when oe = high the outputs are in the high impedance off-state. dir = high indicates the input stage is empty and ready to accept valid data dir = low indicates that the fifo is full or that a previous shift-in operation is not complete (busy) dor = high assures valid data is present at the outputs q 0 to q 8 (does not indicate that new data is awaiting transfer into the output stage) dor = low indicates the output stage is busy or there is no valid data
december 1990 3 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 quick reference data gnd = 0 v; t amb =25 c; t r =t f = 6 ns notes 1. c pd is used to determine the dynamic power dissipation (p d in m w): p d =c pd v cc 2 f i +? (c l v cc 2 f o ) where: f i = input frequency in mhz f o = output frequency in mhz ? (c l v cc 2 f o ) = sum of outputs c l = output load capacitance in pf v cc = supply voltage in v 2. for hc the condition is v i = gnd to v cc for hct the condition is v i = gnd to v cc - 1.5 v ordering information see 74hc/hct/hcu/hcmos logic package information . symbol parameter conditions typical unit hc hct t phl/ t plh propagation delay c l = 15 pf; v cc =5 v mr to dir and dor 21 26 ns so to q n 36 40 ns f max maximum clock frequency si and so 33 29 mhz c i input capacitance 3.5 3.5 pf c p power dissipation capacitance per package notes 1 and 2 660 660 pf
december 1990 4 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 pin description note 1. pin 14 must be connected to gnd. pins 1 and 2 can be left floating or connected to gnd, however it is not allowed to let current flow in either direction between pins 1, 2 and 14. pin no. symbol name and function 1, 2, 14 gnd ground (0 v) 3 dir data-in-ready output 4 si shift-in input (low-to-high, edge-triggered) 5, 6, 7, 8, 9, 10, 11, 12, 13 d 0 to d 8 parallel data inputs 15 oe output enable input (active low) 24, 23, 22, 21, 20, 19, 18, 17, 16 q 0 to q 8 3-state parallel data outputs 25 dor data-out-ready output 26 so shift-out input (high-to-low, edge-triggered) 27 mr asynchronous master-reset input (active low) 28 v cc positive supply voltage fig.1 pin configuration. fig.2 logic symbol. fig.3 iec logic symbol.
december 1990 5 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 applications high-speed disc or tape controller video timebase correction a/d output buffers voice synthesis input/output formatter for digital filters and ffts bit-rate smoothing fig.4 functional diagram.
december 1990 6 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 functional description data input following power-up, the master-reset ( mr) input is pulsed low to clear the fifo memory (see fig.8). the data-in-ready flag (dir = high) indicates that the fifo input stage is empty and ready to receive data. when dir is valid (high), data present at d 0 to d 8 can be shifted-in using the si control input. with si = high, data is shifted into the input stage and a busy indication is given by dir going low. the data remains at the first location in the fifo until si is set to low. with si = low data moves through the fifo to the output stage, or to the last empty location. if the fifo is not full after the si pulse, dir again becomes valid (high) to indicate that space is available in the fifo. the dir flag remains low if the fifo is full (see fig.6). the si pulse must be made low in order to complete the shift-in process. with the fifo full, si can be held high until a shift-out ( so) pulse occurs. then, following a shift-out of data, an empty location appears at the fifo input and dir goes high to allow the next data to be shifted-in. this remains at the first fifo location until si again goes low (see fig.7). data transfer after data has been transferred from the input stage of the fifo following si = low, data moves through the fifo asynchronously and is stacked at the output end of the register. empty locations appear at the input end of the fifo as data moves through the device. data output the data-out-ready flag (dor = high) indicates that there is valid data at the output (q 0 to q 8 ). the initial master-reset at power-on ( mr = low) sets dor to low (see fig.8). after mr = high, data shifted into the fifo moves through to the output stage causing dor to go high. as the dor flag goes high, data can be shifted-out using the so control input. with so = high, data in the output stage is shifted out and a busy indication is given by dor going low. when so is made low, data moves through the fifo to fill the output stage and an empty location appears at the input stage. when the output stage is filled dor goes high, but if the last of the valid data has been shifted out leaving the fifo empty the dor flag remains low (see fig.9). with the fifo empty, the last word that was shifted-out is latched at the output q 0 to q 8 . with the fifo empty, the so input can be held high until the si control input is used. following an si pulse, data moves through the fifo to the output stage, resulting in the dor flag pulsing high and a shift-out of data occurring. the so control must be made low before additional data can be shifted out (see fig.10). high-speed burst mode if it is assumed that the shift-in/shift-out pulses are not applied until the respective status flags are valid, it follows that the shift-in/shift-out rates are determined by the status flags. however, without the status flags a high-speed burst mode can be implemented. in this mode, the burst-in/burst-out rates are determined by the pulse widths of the shift-in/shift-out inputs and burst rates of 35 mhz can be obtained. shift pulses can be applied without regard to the status flags but shift-in pulses that would overflow the storage capacity of the fifo are not allowed (see figs 11 and 12). expanded format with the addition of a logic gate, the fifo is easily expanded to increase word length (see fig.17). the basic operation and timing are identical to a single fifo, with the exception of an additional gate delay on the flag outputs. if during application, the following occurs: si is held high when the fifo is empty, some additional logic is required to produce a composite dir pulse (see figs 7 and 18). so is held high when the fifo is full, some additional logic is required to produce a composite dor pulse (see figs 10 and 18). due to the part-to-part spread of the ripple through time, the flag signals of fifo a and fifo b will not always coincide and the and-gate will not produce a composite flag signal. the solution is given in fig.18. the 7030 is easily cascaded to increase the word capacity and no external components are needed. in the cascaded configuration, all necessary communications and timing are performed by the fifos. the intercommunication speed is determined by the minimum flag pulse widths and the flag delays. the data rate of cascaded devices is typically 25 mhz. word-capacity can be expanded to and beyond 128-words 9-bits (see fig.19).
december 1990 7 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 fig.5 logic diagram. (see control flip-flops) (1) low on s input of flip-flops fs, fb and fp will set q output to high independent of state on r input. (2) low on r input to ff1 to ff64 will set q output to low independent of state on s input.
december 1990 8 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 dc characteristics for 74hc for the dc characteristics see 74hc/hct/hcu/hcmos logic family specifications . output capability: standard i cc category: lsi ac characteristics for 74hc gnd = 0 v; t r =t f = 6 ns; c l = 50 pf symbol parameter t amb ( c) unit test conditions 74hc v cc (v) waveforms + 25 - 40 to + 85 - 40 to + 125 min. typ. max. min. max. min. max. t phl / t plh propagation delay mr to dir, dor 69 25 20 210 42 36 265 53 45 315 63 54 ns 2.0 4.5 6.0 fig.8 t phl / t plh propagation delay si to dir 77 28 22 235 47 40 295 59 50 355 71 60 ns 2.0 4.5 6.0 fig.6 t phl / t plh propagation delay so to dor 102 37 30 315 63 54 395 79 67 475 95 81 ns 2.0 4.5 6.0 fig.9 t phl / t plh propagation delay dor to q n 11 4 3 35 7 6 45 9 8 55 11 9 ns 2.0 4.5 6.0 fig.10 t phl / t plh propagation delay so to q n 113 41 33 345 69 59 430 86 73 520 104 88 ns 2.0 4.5 6.0 fig.14 t plh propagation delay/ ripple through delay si to dor 2.5 0.9 0.7 8.0 1.6 1.3 10 2.0 1.6 12 2.4 1.9 m s 2.0 4.5 6.0 fig.10 t plh propagation delay/ bubble-up delay so to dir 3.3 1.2 1.0 10.0 2.0 1.6 12 2.5 2.0 15 3.0 2.4 m s 2.0 4.5 6.0 fig.7 t pzh / t pzl 3-state output enable oe to q n 52 19 15 175 35 30 220 44 37 265 53 45 ns 2.0 4.5 6.0 fig.16 t phz / t plz 3-state output disable oe to q n 50 18 14 150 30 26 190 38 33 225 45 38 ns 2.0 4.5 6.0 fig.16 t thl / t tlh output transition time 19 7 6 75 15 13 95 19 16 110 22 19 ns 2.0 4.5 6.0 fig.14 t w si pulse width high or low 50 10 9 14 5 4 65 13 11 75 15 13 ns 2.0 4.5 6.0 fig.6
december 1990 9 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 t w so pulse width high or low 100 20 17 33 12 10 125 25 21 150 30 26 ns 2.0 4.5 6.0 fig.9 t w dir pulse width high 10 5 4 47 17 14 145 29 25 8 4 3 180 36 31 8 4 3 220 44 38 ns 2.0 4.5 6.0 fig.7 t w dor pulse width high 10 5 4 47 17 14 145 29 25 8 4 3 180 36 31 8 4 3 220 44 38 ns 2.0 4.5 6.0 fig.10 t w mr pulse width low 70 14 12 22 8 6 90 18 15 105 21 18 ns 2.0 4.5 6.0 fig.8 t rem removal time mr to si 80 16 14 24 8 7 100 20 17 120 24 20 ns 2.0 4.5 6.0 fig.15 t su set-up time d n to si - 35 - 7 - 6 - 36 - 13 - 10 - 45 - 9 - 8 - 55 - 11 - 9 ns 2.0 4.5 6.0 fig.13 t h hold time d n to si 135 27 23 44 16 13 170 34 29 205 41 35 ns 2.0 4.5 6.0 fig.13 f max maximum clock pulse frequency si, so burst mode 9.9 30 36 2.8 14 16 2.4 12 14 mhz 2.0 4.5 6.0 figs 11 and 12 f max maximum clock pulse frequency si, so using ?ags 9.9 30 36 2.8 14 16 2.4 12 14 mhz 2.0 4.5 6.0 figs 6 and 9 f max maximum clock pulse frequency si, so cascaded 7.6 23 27 2.2 11 13 1.8 9.2 11 mhz 2.0 4.5 6.0 figs 6 and 9 symbol parameter t amb ( c) unit test conditions 74hc v cc (v) waveforms + 25 - 40 to + 85 - 40 to + 125 min. typ. max. min. max. min. max.
december 1990 10 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 dc characteristics for 74hct for the dc characteristics see 74hc/hct/hcu/hcmos logic family specifications . output capability: standard i cc category: lsi note to hct types the value of additional quiescent supply current ( d i cc ) for a unit load of 1 is given in the family specifications. to determine d i cc per input, multiply this value by the unit load coefficient shown in the table below. ac characteristics for 74hct gnd = 0 v; t r =t f = 6 ns; c l = 50 pf input unit load coefficient oe si d n mr so 1.00 1.50 0.75 1.50 1.50 symbol parameter t amb ( c) unit test conditions 74hct v cc (v) waveforms + 25 - 40 to + 85 - 40 to + 125 min. typ. max. min. max. min. max. t phl / t plh propagation delay mr to dir, dor 30 51 53 63 ns 4.5 fig.8 t phl / t plh propagation delay si to dir 29 49 61 74 ns 4.5 fig.6 t phl / t plh propagation delay so to dor 39 67 84 101 ns 4.5 fig.9 t phl / t plh propagation delay so to q n 46 78 98 117 ns 4.5 fig.14 t phl / t plh propagation delay dor to q n 7 12 15 18 ns 4.5 fig.10 t plh propagation delay/ripple through delay si to dor 0.9 1.6 2.0 2.4 m s 4.5 fig.10 t plh propagation delay/ bubble-up delay so to dir 1.2 2.0 2.5 3.0 m s 4.5 fig.7 t pzh / t pzl 3-state output enable oe to q n 20 35 44 53 ns 4.5 fig.16 t phz / t plz 3-state output disable oe to q n 19 35 44 53 ns 4.5 fig.16 t thl / t tlh output transition time 7 15 19 22 ns 4.5 fig.14
december 1990 11 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 t w si pulse width high or low 12 6 15 18 ns 4.5 fig.6 t w so pulse width high or low 15 9 19 22 ns 4.5 fig.9 t w dir pulse width high 7 22 37 6 46 6 56 ns 4.5 fig.7 t w dor pulse width high 6 20 35 5 44 5 53 ns 4.5 fig.10 t w mr pulse width low 18 10 23 27 ns 4.5 fig.8 t rem removal time mr to si 18 10 23 27 ns 4.5 fig.15 t su set-up time d n to si - 5 - 16 - 4 - 4 ns 4.5 fig.13 t h hold time d n to si 30 18 38 45 ns 4.5 fig.13 f max maximum clock pulse frequency si, so burst mode 15 26 12 10 mhz 4.5 figs 11 and 12 f max maximum clock pulse frequency si, so using ?ags 15 26 12 10 mhz 4.5 figs 6 and 9 f max maximum clock pulse frequency si, so cascaded 13 22 10 8.6 mhz 4.5 figs 6 and 9 symbol parameter t amb ( c) unit test conditions 74hct v cc (v) waveforms + 25 - 40 to + 85 - 40 to + 125 min. typ. max. min. max. min. max.
december 1990 12 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 ac waveforms shifting in sequence fifo empty to fifo full fig.6 waveforms showing the si input to dir output propagation delay. the si pulse width and si maximum pulse frequency. (1) hc : v m = 50%; v i = gnd to v cc . hct: v m = 1.3 v; v i = gnd to 3 v. notes to fig.6 1. dir initially high; fifo is prepared for valid data. 2. si set high; data loaded into input stage. 3. dir drops low, input stage busy. 4. si set low; data from first location ripple through. 5. dir goes high, status flag indicates fifo prepared for additional data. 6. repeat process to load 2nd word through to 64th word into fifo. 7. dir remains low; with attempt to shift into full fifo, no data transfer occurs. with fifo full; si held high in anticipation of empty location fig.7 waveforms showing bubble-up delay, so input to dir output and dir output pulse width. (1) hc : v m = 50%; v i = gnd to v cc . hct: v m = 1.3 v; v i = gnd to 3 v. notes to fig.7 1. fifo is initially full, shift-in is held high. 2. so pulse; data in the output stage is unloaded, bubble-up process of empty locations begins. 3. dir high; when empty location reached input stage, flag indicates fifo is prepared for data input. 4. dir returns to low; fifo is full again. 5. si brought low; necessary to complete shift-in process, dir remains low, because fifo is full.
december 1990 13 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 master reset applied with fifo full fig.8 waveforms showing the mr input to dir, dor output propagation delays and the mr pulse width. (1) hc : v m = 50%; v i = gnd to v cc . hct: v m = 1.3 v; v i = gnd to 3 v. notes to fig.8 1. dir low, output ready high; assume fifo is full. 2. mr pulse low; clears fifo. 3. dir goes high; flag indicates input prepared for valid data. 4. dor drops low; flag indicates fifo empty. shifting out sequence; fifo full to fifo empty fig.9 waveforms showing the so input to dir output propagation delay. the so pulse width and so maximum pulse frequency. (1) hc : v m = 50%; v i = gnd to v cc . hct: v m = 1.3 v; v i = gnd to 3 v. notes to fig.9 1. dor high; no data transfer in progress, valid data is present at output stage. 2. so set high; results in dor going low. 3. dor drops low; output stage busy. 4. so is set low; data in the input stage is unloaded, and new data replaces it as empty location bubbles-up to input stage. 5. dor goes high; transfer process completed, valid data present at output after the specified propagation delay. 6. repeat process to unload the 3rd through to the 64th word from fifo. 7. dor remains low; fifo is empty.
december 1990 14 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 with fifo empty; so is held high in anticipation fig.10 waveforms showing ripple through delay si input to dor output, dor output pulse width and propagation delay from the dor pulse to the q n output. (1) hc : v m = 50%; v i = gnd to v cc . hct: v m = 1.3 v; v i = gnd to 3 v. notes to fig.10 1. fifo is initially empty, so is held high. 2. si pulse; loads data into fifo and initiates ripple through process. 3. dor flag signals the arrival of valid data at the output stage. 4. output transition; data arrives at output stage after the specified propagation delay between the rising edge of the dor pulse to the q n output. 5. dor goes low; fifo is empty again. 6. so set low; necessary to complete shift-out process. dor remains low, because fifo is empty. shift-in operation; high-speed burst mode fig.11 waveforms showing si minimum pulse width and si maximum pulse frequency, in high-speed shift-in burst mode. in the high-speed mode, the burst-in rate is determined by the minimum shift-in high and shift-in low specifications. the dir status flag is a dont care condition, and a shift-in pulse can be applied regardless of the flag. a si pulse which would overflow the storage capacity of the fifo is ignored. (1) hc : v m = 50%; v i = gnd to v cc . hct: v m = 1.3 v; v i = gnd to 3 v.
december 1990 15 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 shift-out operation; high-speed burst mode fig.12 waveforms showing so minimum pulse width and maximum pulse frequency, in high-speed shift-out burst mode. in the high-speed mode, the burst-out rate is determined by the minimum shift-out high and shift-out low specifications. the dor flag is a dont care condition and a so pulse can be applied without regard to the flag. (1) hc : v m = 50%; v i = gnd to v cc . hct: v m = 1.3 v; v i = gnd to 3 v. fig.13 waveforms showing hold and set-up times for d n input to si input. the shaded areas indicate when the input is permitted to change for predictable output performance. (1) hc : v m = 50%; v i = gnd to v cc . hct: v m = 1.3 v; v i = gnd to 3 v.
december 1990 16 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 fig.14 waveforms showing so input to q n output propagation delays and output transition time. (1) hc : v m = 50%; v i = gnd to v cc . hct: v m = 1.3 v; v i = gnd to 3 v. fig.15 waveforms showing the mr input to si input removal time. (1) hc : v m = 50%; v i = gnd to v cc . hct: v m = 1.3 v; v i = gnd to 3 v. fig.16 waveforms showing the 3-state enable and disable times for input oe. (1) hc : v m = 50%; v i = gnd to v cc . hct: v m = 1.3 v; v i = gnd to 3 v.
december 1990 17 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 application information fig.17 expanded fifo for increased word length; 64 words 18 bits. the pc74hc/hct7030 is easily expanded to increase word length. composite dir and dor flags are formed with the addition of an and gate. the basic operation and timing are identical to a single fifo, with the exception of an added gate delay on the flags. fig.18 expanded fifo for increased word length. this circuit is only required if the si input is constantly held high, when the fifo is empty and the automatic shift-in cycles are started or if so output is constantly held high, when the fifo is full and the automatic shift-out cycles are started (see figs 7 and 10).
december 1990 18 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 expanded format fig.19 shows two cascaded fifos providing a capacity of 128 words 9 bits. fig.20 shows the signals on the nodes of both fifos after the application of a si pulse, when both fifos are initially empty. after a rippled through delay, data arrives at the output of fifo a . due to so a being high, a dor pulse is generated. the requirements of si b and d nb are satisfied by the dor a pulse width and the timing between the rising edge of dor a and q na . after a second ripple through delay, data arrives at the output of fifo b . fig.21 shows the signals on the nodes of both fifos after the application of a so b pulse, when both fifos are initially full. after a bubble-up delay a dir b pulse is generated, which acts as a so a pulse for fifo a . one word is transferred from the output of fifo a to the input of fifo b . the requirements of the so a pulse for fifo a is satisfied by the pulse width of dor b . after a second bubble-up delay an empty space arrives at d na , at which time dir a goes high. fig.22 shows the waveforms at all external nodes of both fifos during a complete shift-in and shift-out sequence. fig.19 cascading for increased word capacity; 128 words 9 bits. the pc74hc/hct7030 is easily cascaded to increase word capacity without any external circuitry. in cascaded format, all necessary communications are handled by the fifos. figs 17 to 19 demonstrate the intercommunication timing between fifo a and fifo b . fig.22 gives an overview of pulses and timing of two cascaded fifos, when shifted full and shifted empty again.
december 1990 19 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 fig.20 fifo to fifo communication; input timing under empty condition. (1) hc : v m = 50%; v i = gnd to v cc . hct: v m = 1.3 v; v i = gnd to 3 v. notes to fig.20 1. fifo a and fifo b initially empty, so a held high in anticipation of data. 2. load one word into fifo a ; si pulse applied, results in dir pulse. 3. data out a /data in b transition; valid data arrives at fifo a output stage after a specified delay of the dor flag, meeting data input set-up requirements of fifo b . 4. dor a and si b pulse high; (ripple through delay after si a low) data is unloaded from fifo a as a result of the data output ready pulse, data is shifted into fifo b . 5. dir b and so a go low; flag indicates input stage of fifo b is busy, shift-out of fifo a is complete. 6. dir b and so a go high automatically; the input stage of fifo b is again able to receive data, so is held high in anticipation of additional data. 7. dor b goes high; (ripple through delay after si b low) valid data is present one propagation delay later at the fifo b output stage.
december 1990 20 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 fig.21 fifo to fifo communication; output timing under full condition. (1) hc : v m = 50%; v i = gnd to v cc . hct: v m = 1.3 v; v i = gnd to 3 v. notes to fig.21 1. fifo a and fifo b initially full, si b held high in anticipation of shifting in new data as empty location bubbles-up. 2. unload one word from fifo b ; so pulse applied, results in dor pulse. 3. dir b and so a pulse high; (bubble-up delay after so b low) data is loaded into fifo b as a result of the dir pulse, data is shifted out of fifo a . 4. dor a and si b go low; flag indicates the output stage of fifo a is busy, shift-in to fifo b is complete. 5. dor a and si b go high; flag indicates valid data is again available at fifo a output stage, si b is held high, awaiting bubble-up of empty location. 6. dir a goes high; (bubble-up delay after so a low) an empty location is present at input stage of fifo a .
december 1990 21 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 fig.22 waveforms showing the functionality and intercommunication between two fifos (refer to fig.19). sequence 1 (both fifos empty, starting shift-in process): after a mr pulse has been applied fifo a and fifo b are empty. the dor flags of fifo a and fifo b go low due to no valid data being present at the outputs. the dir flags are set high due to the fifos being ready to accept data. so b is held high and two si a pulses are applied (1). these pulses allow two data words to ripple through to the output stage of fifo a and to the input stage of fifo b (2). when data arrives at the output of fifo b , a dor b pulse is generated (3). when so b goes low, the first bit is shifted out and a second bit ripples through to the output after which dor b goes high (4). sequence 2 (fifo b runs full): after the mr pulse, a series of 64 si pulses are applied. when 64 words are shifted in, dir b remains low due to fifo b being full (5). dor a goes low due to fifo a being empty. sequence 3 (fifo a runs full): when 65 words are shifted in, dor a remains high due to valid data remaining at the output of fifo a . q na remains high, being the polarity of the 65th data word (6). after the 128th si pulse, dir remains low and both fifos are full (7). additional pulses have no effect. sequence 4 (both fifos full, starting shift-out process): si a is held high and two so b pulses are applied (8). these pulses shift out two words and thus allow two empty locations to bubble-up to the input stage of fifo b , and proceed to fifo a (9). when the first empty location arrives at the input of fifo a , a dir a pulse is generated (10) and a new word is shifted into fifo a . si a is made low and now the second empty location reaches the input stage of fifo a , after which dir a remains high (11). sequence 5 (fifo a runs empty): at the start of sequence 5 fifo a contains 63 valid words due to two words being shifted out and one word being shifted in in sequence 4. an additional series of so b pulses are applied. after 63 so b pulses, all words from fifo a are shifted into fifo b . dor a remains low (12). sequence 6 (fifo b runs empty): after the next so b pulse, dir b remains high due to the input stage of fifo b being empty (13). after another 63 so b pulses, dor b remains low due to both fifos being empty (14). additional so b pulses have no effect. the last word remains available at the output q n .
december 1990 22 philips semiconductors product speci?cation 9-bit x 64-word fifo register; 3-state 74hc/hct7030 package outlines see 74hc/hct/hcu/hcmos logic package outlines .

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