No output from DAC @STM32F103VExx

rajan2 · ‎2012-04-10

Posted on April 10, 2012 at 17:50

Hi,

I am a university undergrad and I am designing a Digital storage oscilloscope. I need the micro controller's DAC output for DC voltage. I have seen the sample code and I know how to setup the timer, link the DMA to DAC. The code seems to be working fine on STM32VLdiscovery board, but when I run it on my STM32F103VET6 processor there is no output from DAC i.e. 0V. I would like to clarify:

- I have made the board myself but I have made sure that all the connections are as per the datasheet.

- I have given Vref+ as 3.3V , Vref- as GND as well. All the decaps are in place too.

- All other peripheral are working fine, it is just the DAC which does not seem to be working.

One problem could be with the DAC 12-bit right align config adddress i.e.

&sharpdefine DAC_DHR12RD_Address 0x40007420.

I reckon this should be different for STM32f103VExx than STM32f100RBxx. The code is exactly the same as ''DualModeDMA_SineWave''.

Thankyou

#dac-dma-tim2

rajan2 · ‎2012-04-10

Posted on April 10, 2012 at 17:59

Alright. I just saw clive1's solution in one of the previous discussions(

https://my.st.com/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/Flat.aspx?RootFolder=https://my.st.com/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/dac configuration&FolderCTID=0x01200200770978C69A1141439FE559EB459D7580009C4E14902C3CDE46A77F0FFD06506F5B&currentviews=517

). apparently there was a very easy solution which does not require any DMA or timers(I don't want them either). I tried that code and it seems to be working fine now. Kudos man.

Tesla DeLorean · ‎2012-04-10

Posted on April 10, 2012 at 18:15

Are you sure it is EXACTLY the same?

The \STM32F10xFWLib\Examples\DAC\DualModeDMA_SineWave\main.c uses TIM8 not TIM2

The two DAC channels should come out of PA.4 and PA.5, and the addresses should be the same on all STM32F10X parts.

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rajan2 · ‎2012-04-10

Posted on April 11, 2012 at 02:38

No I am pretty sure it is TIM2, I just checked it. Thank you for you reply but anyway I am not changing the DAC output very frequently. So using DAC_SetChannelxData() works just fine, DMA is not necessary. And yeah I am aware of the DAC output pins.

-rajan