Battling to configure/access STM32F205ZE DMA

[Spencer.Andrew]

Posted on November 29, 2012 at 09:45

I am trying to use DMA1 Stream 1 Channel 4 in the STM32F205ZE

 (IAR Embedded Workbench IDE).   Attempts to configure the DMA (using the Std Peripherals library) result in no change in the register values (all values remain zeroes).   Attempts to write directly to the register memory also make no change.   (Doing the same thing with, say, UART3, works fine).

Any ideas why the memory around 0x40026000 might remain resistant to my attempts to configure it?

Thanks

0x40004808 OK

#dma-stm32

[waclawek.jan]

Posted on November 29, 2012 at 09:59

You might have forgotten to enable the clock for DMA1 in RCC (in RCC_AHB1ENR).

JW

[Spencer.Andrew]

Posted on November 29, 2012 at 12:02

Thanks, but no - the line

RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_DMA1, ENABLE);

is in place.

[Tesla DeLorean]

Posted on November 29, 2012 at 13:35

Thanks, but no - the line  RCC_AHB1PeriphResetCmd(RCC_AHB1Periph_DMA1, ENABLE); is in place.

No you need to enable the CLOCK, not RESET the peripheral.

[waclawek.jan]

Posted on November 29, 2012 at 15:04

This is a recurring problem here. The ''instructions'' in the ehm ''library'' are faulty.

JW

[Spencer.Andrew]

Posted on November 29, 2012 at 23:11

Curses!   Copying and pasting the ''RCC_AHB1PeriphClockCmd'' with so many peripherals being enabled.   Somewhere along the line I ended up with ''RCC_AHB1PeriphResetCmd'' in the clipboard, and it looks similar to ''RCC_AHB1PeriphClockCmd'' when you have lots of lines of code!  

Thanks.   Better now.