PCF8583P (NXP)

The PCF8583P is a Clock and Calendar Chip, based on a 2048 bit static CMOS RAM organized as 256 words by 8 bits. Addresses and data are transferred serially via the two-line bidirectional I?C-bus. The built-in word address register is incremented automatically after each written or read data byte. Address pin A0 is used for programming the hardware address, allowing the connection of two devices to the bus without additional hardware. The built-in 32.768kHz oscillator circuit and the first 8bytes of the RAM are used for the clock, calendar and counter functions. The next 8bytes can be programmed as alarm registers or used as free RAM space. The remaining 240bytes are free RAM locations.