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STM32F103RB - Different Clock Speed Between Reset?

Question asked by cooper.ian on Mar 2, 2014
Latest reply on Mar 31, 2014 by Andrew Neil
Afternoon all,

I am having some problems with clock rate setting on the stm32f103 and I am hoping you can point me in the correct direction. (I think this is a very simple problem!).

First up I do not have a scope on me at the moment to check the clock out pin. Hopefully I will be able to check this soon.

Anyway the problem. I have a board that uses an Xbee radio for wireless comms. Some simple code I have setup (And working) prints wirelessly to terminal Buad rate set in code to 9600. This works perfectly after flashing the board and the xbee transmits perfectly. However, when I do a power reset on the board the Xbee begins communicating incorrect data (common problem I have seen with having the baud rate set wrong).

I assume this is because on 'startup' the board is/isn't setting the clock speed correctly and since the buad rate is calculated using this it is causing problems. Am i missing something obvious?

On my stm32f100rb (discovery board), I do not seem to have this same issue.

Thanks all, any advice is much appreciated.
Iam

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