Interfacing PCF8583 Real Time Clock

The project shows how an AVR microcontroller is used to interface with PCF8583 Real Time Clock.

A 2048-bit static CMOS RAM organized as 256 words by 8 bits is the basis of the PCF8583 clock/calendar circuit. The serial transfer of addresses and data are done through the 2-line bidirectional I2C bus. Automatic increment is done on the built-in word address register after each written or read data byte. The hardware address is programmed using the address pin A0 which allows the connection of two devices to the bus without additional hardware. The clock/calendar and counter functions are using the built-in 32.768kHz oscillator circuit and the first 8 bytes of the RAM while the next 8 bytes may be programmed as alarm registers or used as free RAM space with free RAM locations on remaining 240 bytes.

The I2C-bus interface operating supply voltage is 2.5V to 6V while the clock operating supply voltage ranges from 1.0V to 6V as well as the data retention voltage. The universal timer used has alarm and overflow indication and the clock is functioning with four year calendar. The alarm, timer, and interrupt function are programmable with slave address.

Rest of the project