Dears
Problem: Due to the shortage of board resources, it is currently necessary to expand the output port. In the first test, GPIO34 was used. After checking DATASHEET, it was found that GPIO34 and GPIO37 determine the startup mode, which will cause the board to boot incorrectly and the board will not run.
Currently considering whether to use the three feet in JACK:
GPIO35 TDI
GPIO36 TMS
GPIO38 TCK
I don’t know if it can be used, some tests have been done
1. Configure the output port:
GPIO35 is normal
GPIO36 is abnormal and cannot be high level
GPIO38 is normal
2. Configured as input port:
GPIO35 is normal
GPIO36 is normal
GPIO38 is normal
3 After matching the input and output, use the emulator to simulate, no obvious problems are found, and the simulation can be normal.
At present, it is considered to be used as follows. I don't know if it is possible. Use the small board connector, plug it into the JACK when using it, and unplug it when simulation is needed.
GPIO35 output
GPIO36 input
GPIO38 input
Thanks
Elsa Duan
