The Microcontroller programs but it's not working!

[Mujtaba]

Posted on February 27, 2017 at 15:46

Dear Friends,

I have designed two identical PCB boards and I used stm32f103rbt6 microcontroller.

One of them works properly but the other one has a problem which I cannot understand.

The micro programs successfully but it is not working!!!!

I have checked every traces and ICs on the PCB board and there in no problem.

I wonder if you could help me in finding the problem.

Is it possible while soldering, micro find some problems?

(Both micros have the same program.)

[AvaTar]

Posted on February 27, 2017 at 16:05

Misplaced or wrong components ?

A cold solder joint ?

Supply voltages o.k. ?

After checking that, I would try to debug the board.

[Mujtaba]

Posted on February 27, 2017 at 16:32

I have checked the supply voltage and components. There is no problem.

But during soldering, the micro became a little bit warm and I doubt if that harmed micro, would it still done programming?(since when I download my codes in the micro using st link v2 in SWD mode, it finishes programming.)

[Tesla DeLorean]

Posted on February 27, 2017 at 16:59

You'll need to utilize a debugger and diagnostic skills to refine 'doesn't work' into some specific causal reason.

Make sure the BOOT0 pin is pulled LOW

[Mujtaba]

Posted on February 27, 2017 at 19:01

When I wanted to check the micro, I set one of its pins and I used a voltmeter to see if it's high or not and it was around 2v which is considered to be low!

And the BOOT0 pin is pulled low using a 10kohms resistor.

I think i must change the micro.

[AvaTar]

Posted on February 27, 2017 at 19:42

I set one of its pins and I used a voltmeter to see if it's high or not and it was around 2v which is considered to be low!

It actually matters which pin. And 2Volt is not 'low', but rather logically undefined/illegal. Most probably in high-Z mode.

Attach a debugger, and see if you can step into the reset handler.

[AvaTar]

Posted on February 28, 2017 at 09:11

>>

I think i must change the micro.

That is one course of action, two boards isn't really a good statistical sample.

And,  this course of action does not give you any insight what was/is wrong with that second one.

There is a good chance of repeating this story with the next batch of boards ...