Introduction - If you have any usage issues, please Google them yourself
The experiment will achieve the following functions: a running program is open IWDG, and makes DS0 lit, kept inside the main loop detection WK_UP button is pressed, if pressed, feed the dog, or wait watchdog reset. Watchdog reset can see DS0 stop flashing. Note: 1, the code can JTAG (SWD) download, but does not support the simulation (simulation error). 2, 1820, and not to jump on PA0 jumpers, otherwise it may cause the button " not working."