Continuing rebooting STM32f0discovery board

evert2 · ‎2012-11-08

Posted on November 08, 2012 at 10:51

Dear All,

After playing around with my new STM32F0Discovery board, it looks like that it has entered a kind of reset state. It continuously generates NRST signals with an interval of 400ms, even when i have clear the flash memory by using the ST-link utility.

These signals from high to low start a few seconds from clearing this memory.

I also have tried to start from system memory but this has no effect. I also tried to remove the option bits.

When I load some binary the reset signals imediatly starting.

Due to this problem the application is restarting continiously

Are there some more registers which can cause this issue? or is there a way to return to the initial state of the discovery board?

Regards,

Evert

#nrst-pin-problem-trouble-stm32

frankmeyer9 · ‎2012-11-08

Posted on November 08, 2012 at 11:14

Such an intervall and of consistent length, sounds like a watchdog hit.

Have you tried a mass erase, to remove your application ?

evert2 · ‎2012-11-08

Posted on November 08, 2012 at 11:35

Yes, the ST link utility is performing a mass erase when you select the erase button.

I've verified this by looking into the flash sectors, and they are all set to 0xFF

Evert

Tesla DeLorean · ‎2012-11-08

Posted on November 08, 2012 at 13:22

I guess I would look at the supply voltages at the regulator.

Might also review the option byte settings.

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frankmeyer9 · ‎2012-11-08

Posted on November 08, 2012 at 15:00

I can't see a SW related reason here.

Did you check the current consumption ?

Do some voltage regulators get hot ?

I had spurious fails when trying to supply a F4_Discovery with a 320x240 TFT display attached from the USB port.

Your resets could be brownout-related, but that would rather not be that regular IMHO.

evert2 · ‎2012-11-09

Posted on November 09, 2012 at 09:55

I've verified the power regulator with my scope and it seems a stable signal of 3v3

I use the power supply of the USB port but also an external power supply doen't help.

The regulator is not hot.

Another question, on the discovery board, R33 (pull-up of the reset button) is not mounted by default. I've not verified completely but a quick try learns that mounting this resistor will help. Why is this not mounted by default?

Evert Huijben

evert2 · ‎2012-11-09

Posted on November 09, 2012 at 09:56

I've verified the power regulator with my scope and it seems a stable signal of 3v3

I use the power supply of the USB port but also an external power supply doen't help.

The regulator is not hot.

Another question, on the discovery board, R33 (pull-up of the reset button) is not mounted by default. I've not verified completely but a quick try learns that mounting this resistor will help. Why is this not mounted by default?

Evert Huijben

frankmeyer9 · ‎2012-11-10

Posted on November 10, 2012 at 18:42

Why is this not mounted by default?

You might ask ST here.

According to the datasheet, the NRST pin has an internal pullup of 30 ... 50 kOhm, so an external one is not absolutely necessary.

evert2 · ‎2012-11-26

Posted on November 26, 2012 at 14:41

Hi,

I've resolved the issue, the problem is the option byte.

Within the ST link utility 'option bytes' menu all 'user configuration option byte' items needs to be enabled.

I thougt they should be disabled by default

Evert Huijben