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32F429IDISCOVERY SDRAM(FMC) and PG2 pin problem

Question asked by machala.petr on May 14, 2015
Latest reply on May 15, 2015 by machala.petr
Hi,
I have a very strange problem with the SDRAM controlling and PG2 pin use. I use SDRAM as an additive memory space so it is vital for my program because I do calculations that need a lot of space. This works very well. I just move memory allocations by _sbrk() to SDRAM. But recently I added a NPN tranzistor with external pullup to PG2 pin and this causes the SDRAM(FMC) to crash and MCU goes to default handler (infinite loop)...

I dont get how pin that is NOT part of the SDRAM at all can do something like that. If the PG2 pin is configured as OUT and is set like GPIO_SetBits then it fails. If I for example just initialize the pin and leave it as GPIO_ResetBits then its fine...

Thanks very much for any ideas...

BTW the pin PG2 affects data too...For example if I leave it in reset state then the LED is ON ad if I connect the pin manualy to VCC then the LED is trned off and the data is affected...Personally it seems to me that he SDRAM(FMC) uses this pin but its impossible...

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