RESET not working when using external ST-LINK/v2 to program and debug NUCLEO STM32F103RB

Arjun Oberai · ‎2018-01-03

Posted on January 04, 2018 at 08:21

I am programming and debugging Nucleo STM32F103RB using external ST-LINKv2. To use the external ST-LINKv2 I have removed SB2 and SB12 from the Nucleo Board (Please see the Image for the function of specific SB).

I have connected all the pins as shown in the attached image.

I am able to program the MCU on nucleo board but it runs when I turn the power OFF and then On(Power on reset I suppose) and it doesn't run when I just load the code to the flash. The program stops running when I press Reset Button B2 on the nucleo board . (I was running the blinky example program)

Even when I have to debug the program, I load the code and then turn off and then on the supply and then the debug works. (It doesn't works when I debug right after Loading the code to the flash)

My assumption: The Reset is floating that's why once it is given reset the program doesn't boots again.

Please suggest me what could be done or what the problem is so that I can use the reset button and get the normal behavior.

PS: I am doing this because I am using this MCU in the PCB I am designing and I will be programming my PCB using the ST-LINKv2.

Thank You in advance.

#stm32f103rb #nucleo #st-linkv2 #reset-problem

Andrew Neil · ‎2018-01-04

Posted on January 04, 2018 at 10:05

My assumption: The Reset is floating

So what have you done to verify that assumption?

Have you looked at the schematic to verify that the point at which you are attaching your external Reset signal is actually routed to the STM32's NRST pin ?

Arjun Oberai · ‎2018-01-04

Posted on January 04, 2018 at 23:40

I haven't verified because the assumption is based on the behaviour where the reset gets a low pulse but it does not go high again untill given a POR. I don't know how to verify it. The NRST that I have connected from my ST-LINK/v2 is connected to the internal NRST pin which I have tested by doing a conectivity test. When I press the reset button(B2) the NRST that I have connected to CN6 goes low(0V) and then it turns high(3.3V) when the reset button(B2) is released(This is verified measuring volatages on multimeter).