To control MPSSE mode, the application running on the system MCU must call a sequence of OPCODE – DATA – OPCODE – DATA, etc. The example on this slide shows how to set the frequency of the clock which data will be clocked in or out of the FT4232H chip. The value 0x86 is the opcode or instruction for setting the clock, while the next two bytes in the buffer are the parameters for the instruction to work on, the divisor values for the master clock. When a buffer of data is created containing both opcode and data the FT_Write command can be used to send it to the FT43232H device to be acted upon.