Chris Parris
Microchip Technology

The 25XXX series serial EEPROMs from Microchip Technology are SPI compatible and have maximum clock frequencies ranging from 3 MHz to 20 MHz. Many times when designing an application which utilizes a serial EEPROM device, it may be beneficial to use a microcontroller which does not feature a dedicated protocol-specific serial port. In these instances, it is required of the designer to write software routines capable of generating the proper signals for communicating with the EEPROM device. This application note provides assistance and source code to ease the design process of interfacing a Microchip PIC18F1220 PICmicro microcontroller to a Microchip SPI serial EEPROM, without the use of a hardware serial port.