SPI is a 4 wire, synchronous serial protocol. There is no official SPI specification but it has become a de facto standard. Its low cost implementation (essentially 2 shift registers) contributed to wide spread adoption and inclusion in most microcontrollers and a wide variety of peripheral ICs.
The SPI Protocol Analyzer is one of many signal decoders included with all DigiView Logic Analyzers.
The DigiView software provides extensive navigation, search, measurement, export, plot and printing capabilities to all signal types. The SPI Bus Protocol Analyzer adds SPI Bus specific decoding and configuration options.