STM32F4 not fully programable

[Lukasz Przenioslo]

Posted on September 19, 2016 at 12:42

Hello there,

I have a problem with programming STM32F4 device. My Jlink probe correctly sees the device over SWD but it cannot erase nor program it however- This is the Jlink command prompt when trying to erase:

https://pastebin.com/6S4KKFAZ

Some facts about the enviroment that might help resolve the issue: - I am able to program the same MCU on a different board with the same code. - I am able to connect with the device using Segger Jlink device, but I am not able to erase or program. - The device stopped working after about 2 h of proper work. The program stopped and I reset the power. After that I have the current problem... - I have checked the voltage on the device (it is also visible in the Jlink command prompts) and it is within proper range. - I have resoldered another STM32F407 MCU to make sure the MCU is not broken. What could be the case of this situation? If this might be hardware related, what could be the case? I believe that if the ribbon cable connecting the board with the debbuger was faulty, I wouldnt be able to connect at all? I would really appreciate all help, I am getting out of ideas...

[Lukasz Przenioslo]

Posted on September 20, 2016 at 15:12

Hi, thanks for answer.

The VREF has a proper value and also the JLink programmer reads it fine as well.

[Tesla DeLorean]

Posted on September 20, 2016 at 15:52

Also keep in mind the ST-Link uses non standard VCC connection to allow supply of STM32 while programming without external power, JLink does not have this to my knowledge, you have to supply the STM32 from external source. Here comes to play the VREF, that has to be detected properly.

J-LINK's have historically pushed ~5V out of pin 19 to power boards. Pin 1 & 2 are often connected on the target board and provide a supply to the JTAG buffers on the pod.