The SPI controller is provided by the Atmel CPU. We provide sample code to set up the SPI port and initiate a write to an SPI flash device. This is used to demonstrate a simple read and write, as well as a more complex overall process. A TS-4200 compatible binary is available here with the sources available here.
Documentation for the CPU SPI peripheral can be found in the CPU manual in section 30 (page 391).