Abstract: This article explains how to interface a GPIO port to an SPI peripheral. It defines the basics of the SPI protocol, the signals and the four transfer variations for the SCK signal. A software routine is included to implement the SPI interface using the MAX7651, a flash programmable 12-bit integrated data-acquisition system. Maxim > App Notes > A/D and D/A CONVERSION/SAMPLING CIRCUITS INTERFACE CIRCUITS Keywords: SPI, SPI interface, SCK, MOSI, MISO, CS, I/O ports, bit banging, SPI peripheral. Sep 17, 2001 APPLICATION NOTE 802 Interfacing SPI Peripherals to the MAX7651 Processor Abstract: This article explains how to interface a GPIO port to an SPI peripheral. It defines the basics of the SPI protocol, the signals and the four transfer variations for the SCK signal. A software routine is included to implement the SPI interface using the MAX7651, a flash programmable 12-bit integrated data-acquisition system. Introduction The SPI bus is a 4-wire serial communications interface used by many microprocessor peripheral chips. The MAX7651 microprocessor does not include dedicated hardware ……