MPSSE Application Example:
http://ftdichip.cn/Support/SoftwareExamples/MPSSE.htm
MPSSE: AN_129 FTDI USB To JTAG TAP Example
MPSS: AN_114 FTDI USB to SPI Example
MPSSE: AN_113 FTDI USB to I2C Example
MPSS: AN_114 FTDI USB to SPI Example
FTDI MPSSE(Multi-Protocol Synchronous Serial Engine)
Using the MPSSE can simplify the synchronous serial protocol (USB to SPI, I2C, JTAG, etc.) design. This application note focuses on the hardware and software required to emulate a connection to a SPIusing the FT2232H. The FT232H and FT4232H can also be used with the example in this document, though pin-out and port selection will need to match the respective part.
Users can use the example schematic and functional software code to begin their design.
Note that software code listing is provided as an illustration only and not supported by FTDI.