STM32H747i j-tag debugging

[Heisenberg]

Hello everyone,

I am currently working on the SMT32H747i_DISCO board and I was wondering if it is possible to use the Segger J-Link debugger on the Board. There is a j-tag pin out connected to the Dev board which suggests that it should be possible. I didn't have any luck so far. Are there additional ports necessary? Am I missing something. I can't find any documentation to the purpose of the connection. Thanks for any help.

Regards Maikel

[Andrew Neil]

See the Segger documentation for supported microcontrollers, but the J-Link's big claim to fame is that it works with pretty much every ARM Cortex-M there is.

The board says it has an On-board STLINK-V3E debugger/programmer - are you sure you have disabled/disconnected that before trying to use the J-Link?

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@Heisenberg wrote:

I didn't have any luck so far. Are there additional ports necessary? Am I missing something. I can't find any documentation to the purpose of the connection. Thanks for any help.

Regards Maikel

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So what, exactly, did you try?
What, exactly, was/were the problem(s) you experienced?

Segger has a page on how to debug connection problems:

https://wiki.segger.com/J-Link_cannot_connect_to_the_CPU 

[Tesla DeLorean]

>> Am I missing something.

Hard to say, not party to anything you wired or tested.

SWO/TDO (PB3) would be generally helpful for the debug communications channel.

Not sure what you need JTAG for, you'll need the full complement if you want to boundary scan or daisy chain.

Should be able to wire the standard ARM 10-pin connector if you need that, and can spare the pins.

[Andrew Neil]

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@Heisenberg wrote:

I can't find any documentation to the purpose of the connection. Thanks for any help.

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It's in the User Manual - UM2411:

So it's a TAG-Connect 10-pin footprint.

This is a 10-pin TAG-Connect:

https://www.tag-connect.com/product/tc2050-idc-nl-10-pin-no-legs-cable-with-ribbon-connector 

Details relating to J-Link:

https://www.tag-connect.com/debugger-cable-selection-installation-instructions/segger-j-link

https://www.segger.com/products/debug-probes/j-link/accessories/adapters/10-pin-needle-adapter/ 

"DAP" is the Debug Access Port

The "TAG Connector" is here:

The pinout is here:

[Heisenberg]

So I flashed a Zephyr example blinky application via west flash to the board (Using the st-link connection). The led blinks. Connected the Segger J-Link debugger to the development board via the 10 PIN STDC connector CN13. I didn't change any power sources. The J-Link debugger gets detected and a attempt is made to flash the code via Ozone to the board. A error appears with connection failed. The reason why I want to use J-Link is because it has Zephyrs RTOS awareness, a feature that is widely missing with ST-Link.

Regards Maikel

[Andrew Neil]

So, again, have you disabled/disconnected the onboard ST-Link before trying to use the J-Link?

[Andrew Neil]

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@Heisenberg wrote:

 reason why I want to use J-Link is because it has Zephyrs RTOS awareness, a feature that is widely missing with ST-Link.

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Segger have updates to convert (some of) the on-board ST-Links to J-Link - you could look into that?

[Heisenberg]

Hi Andrew,

Yes I looked into that. This board isn't supported however. Unfortunately. Thanks for the input tough.

Regards

[Heisenberg]

I didn't find any instructions on how to achieve that. I used the j-link debugger on other boards and there wasn't a need for any disable or disconnect operations.

regards

[Tesla DeLorean]

I don't think any of this is related to using JTAG vs SWD.. The extended standards do allow for a multi-drop SWD connection to multiple cores.

It likely disconnects from a host of other reasons. The pin configurations get changed, or disabled. Or the part is put into a power down situation where all the pin drivers and scan chains are turned OFF, and further communications then become improbable. Check DBGMCU settings.

Look at these types of things first.