3.3V, 32 Mbit (1024 KBit x 32) TIMEKEEPER® SRAM Multi-channel clock distribution circuit Serial real-time clock with 44 bytes NVRAM and reset Serial I2C bus RTC with battery switchover 3.3V, 32 Mbit (1024 KBit x 32) TIMEKEEPER® SRAM 模拟IC Serial SPI bus RTC with battery switchover 模拟IC