I’m currently writing code for QN908X dev kit and I’m having issues programming my dev kit using my j-link plus debugger via SWD. In the QN908x DK User’s Guide it states that the 9-pin debug connector is for programming “off-board” targets which tells me this is simply for programming other arm cortex chips. When I looked at the schematic section of the same user’s guide I also noticed that the debug connector’s IO lines run directly to the LPC MCU (ISP programmer) instead of the QN9080 chip which makes sense because the LPC is acting as the ISP.
So my questions are:
1. is my understanding correct that the debug connector is simply for programming other chips – this seems odd to me because I typically see a jumper option to disable the ISP and use the external debug connected.
2. If my understanding is correct, is there a recommended approach for using an external J-Link debugger? I'm currently looking into hacking up my dev board (going to start cutting traces) but before I do I wanted to see if perhaps I'm missing something.
3. Is there a pdf for just the schematic, the schematic drawings in the User's Guide are not the best quality. In some cases I can't read part numbers, and if I zoom in too much the image gets very pix-elated.
BTW, I can program the board just fine using the ISP along with properly configuring my IDE’s CMSIS DAP settings. Although I need to verify that we can use an external swd interface for validating our new hardware.