Portenta H7: external debugger

[tjaekel]

Some people might ask: "how to connect a debugger on Portenta H7?"

• the Portenta H7 MCU module does not have a debugger connector (just tiny solder pads)
• you need the Breakout Board, or the Vision Shield (both provide the debugger header)
• STLINK-V3 comes with a ribbon cable which fits
• using the STLINK-V3MINI: you need an adapter (or similar cable to build)

Here, how the debugger connection looks like:

Remarks:

Even the debugger has a T_VCC pin - it does not provide power for the target! Instead, it is used in order to sense (measure) the target VDD so that debugger can adapt the debug signals (e.g. 3V3 vs. 1V8 on MCU).

The GNDDetect signal is not signal ground (use one or the two other GND). It is used by debugger to realize if there is a cable connection to the target.

T_VCC and GNDDectect have to be connected: otherwise, the debugger will complain all the time that it does not find the target.

SWO (used for SWV, the SWO Viewer, for debug messages via debugger), could conflict with a pin function, e.g. PB3 as SPI1_SCK, SPI6_SCK. If you want to use SPI1_SCK on PB3 - you can let this wire connected with debugger, but you cannot make use of SWV. The SD Card on Breakout Board, Vision Shield, uses SDMMC1, so that the conflict with SDMMC2_D2 is not there.

[tjaekel · Accepted solution]

You could try to place the debugger female header on the Portenta H7 debugger male pins, but with an offset of one column (leave pin 1 and 2 unconnected, "free hanging"). But the additional male pins might make it impossible to place the female header properly on it.
I would not shorten the female header to make it working (neither bend pins): it will make the pressed on ribbon cable loose.

Create an adapter with a female through hole header (remove/shorten the not needed legs) or create a ribbon cable (10 gauges needed).