So I've already went through these topics:
- "STM32 & ST-LINK - SWD connector not working"
I cannot access on-board target with the on-board ST-LINK.
Things I have researched:
Computer can detect the on-board ST-Link via USB, but when trying to connect to the on-board target I get the same result from the utility as the first link - "Can not connect to target!" Also tested with the slowest CLK frequency and different modes - nothing. I can see and have measured that the on-board target STM32F0308Rx does 3-4 resets while connecting and then I get that message from the utility.
I have reinstalled ST-Link Utility and manually reinstalled the USB drivers as well. I am on Windows 10 Pro. Also the on board ST-LINK got updated to V2.J33.S0 - maybe I need to downgrade ?
I can access the on-board target with an external ST-LINK V2 - no problems there - I can flash the target and run the code. So I'm guessing there's something wrong somewhere between the on-board ST-LINK and the target but I cannot put my finger to it.
I have double checked the connections from the on-board ST-Link to the on-board target - when jumpers are mounted, the connections are to the correct pins PA13 and PA14 - continuity check is OK.
I have tried to cross examine the Discovery board to the default PCBA pictures found on the internet, it SEEMS that no component is missing or added on the board (I didn't get this board brand new - so I'm not 100% sure what has been done with it). I have all the PCB files at hand as well and so far haven't found anything out of place between design and PCB.
So I think I have exhausted most of my ideas. Anything else I should check ? Or should the target have smth to use the on-board ST-LINK ? I have fully erased the target flash with external ST-LINK.
I really would like to use the on-board ST-LINK - make sure the board is OK, as this saves me a bit of trouble (plan B is to keep using the external ST-LINK)
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I've done probing around the board and Found out that the on-board ST-LINK uC STM32F103 pin 27 is shorted to it's VSS pins. But only that GPIO.
The R14 resistor was also blown to open circuit as it seemed - so I'm assuming that the T_JTMS signal was blown on that micro - thus kind of rendering that chip useless to ever connect to on-board target. Other than that it works.
OR is there any way to configure T_JTMS pin to some other pin with some FW wizardy ? I could maybe also get a new bare chip, mount it on an adapter board, somehow get the ST-LINK FW (I think I saw some custom one on EEVBlog) and flash it with the external ST-LINK? dunno, maybe any other ideas ?