Beyond the SW APIs (used for the communication between the host computer and the USB FX2 microcontroller), another set of firmware (FW) API exists: this set is called "API Commands". The SW program running on host computer sends API commands to the USB FX2 microcontroller and/or Xilinx MicroBlaze embedded processor by means of the following SW API functions:
The USB FX2 microcontroller and/or Xilinx MicroBlaze soft embedded processor is(/are) able to execute the command. Skilled users can extend the FW API Command modifying USB FX2 microcontroller firmware (and MicroBlaze SW if necessary, but in many case is not necessary).