[Help on DAC Repair] ARM STM32 replacement and memory reading ?

[matthieu.e]

Hi

I need your help because I am stuck on a DAC repair. From what I see, 2 IO on the STM32 on my board are in short circuit. I need to replace the Arm STM32 chip but I don’t know if it is possible and where to start.

Is it possible to read the memory from the chip and clone it to a new one ?

What hardware and software do I need to read the memory if not protected in the chip ?

Perhaps I can replace the chip and try to find the firmware if I contact the company ?

[pcprogrammer]

When there is no protection on the FLASH inside the STM32, then it should be possible to read out the FLASH memory and load it into a new one. Otherwise it becomes a bit tricky but there might be ways around it. There are threads on reading protected STM32 FLASH memory here on the forum.

But are you sure that the shorted IO pins are due to the STM32 being defective or could it be another part of the circuit that is pulling these signals to ground.

To read the FLASH of the STM32 a ST-link V2 will do. A clone like this is cheap: https://www.aliexpress.com/item/1005005494623572.html

For the software I make use of openocd. There are other programs that can be used of course and it depends on which OS you are on what will work for you. Plenty of information to be found online on how to do this type of thing.

The image of part of the board does not show if there is a SWD or JTAG connector on the board to easily connect to the STM32 chip. So either post a full picture of both sides of the board, or mention the make and model of it.

[matthieu.e]

Hi Pcprogrammer,

Thank you for the detailed answer. Yes I tried to lift the PIN on the ARM chip and the short circuit is gone. 
I am now sure I need to replace this chip.

I ordered a ST link V2 programmer from your link. It should be soon here.

I attached some pictures of the board. There is a MCU port. Is it te programming IO ?

[pcprogrammer]

I attached some pictures of the board. There is a MCU port. Is it te programming IO ?

It could be. For the ST-Link V2 the SWDIO and SWCLK signals are needed. These are on PA13 and PA14, pin 46 and 49 on the LQFP64 package. They appear to go to via's right next to the MCU, so you have to trace them to the connector.