Introduction - If you have any usage issues, please Google them yourself
Sandstorm first-generation family, with the GPIO multiplexing JTAG can be directly configured. But it is not enough security, the configuration of the accident may have led to JTAG connection failure. Fury for the second generation and third generation DustDevil family, because of the protection register GPIOLOCK etc., relevant Pin function defaults to JTAG configuration does not allow for direct GPIO function. If it is configured as GPIO function, you must first unlock operation implementation. GPIO detailed documentation and routines.