The 25XXX series serial EEPROMs from Microchip Technology are SPI compatible and have maximum clock frequencies ranging from 3 MHz to 20 MHz. The SPI module available on dsPIC33F Digital Signal Controllers provides a very easy-to-use interface for communicating with the 25XXX series devices. The largest benefit of using the SPI module is that the signal timings are handled through hardware rather than software. This allows the firmware to continue executing while communication is handled in the background. This also means that an understanding of the timing specifications associated with the SPI protocol is not required in order to use the 25XXX series devices in designs.

This application note is intended to serve as a reference for communicating with Microchip’s 25XXX series serial EEPROM devices with the use of the SPI module featured on many dsPIC33F family devices. Source code for common data transfer modes is also provided.