ADC/DMA one off problem

[mrost9]

Posted on April 06, 2010 at 10:38

ADC/DMA one off problem

[Tesla DeLorean]

Posted on May 17, 2011 at 13:46

Sounds like you are glitching the DMA while you are setting up the ADC, and changing the settings. Perhaps you should get everything set up properly *before* enabling the DMA to accept transfers?

This should be less prone to that     ADC_StartCalibration(ADC1);     while(ADC_GetCalibrationStatus(ADC1));     /* Enable DMA1 channel1 */     DMA_Cmd(DMA1_Channel1, ENABLE);     ADC_SoftwareStartConvCmd(ADC1, ENABLE);

[mrost9]

Posted on May 17, 2011 at 13:46

Thanks, that sounds logical.

I didn't think of it as a possible problem, as the ADCx_DMA examples do it in the same order. I'll try it.

[daviddavid942]

Posted on May 17, 2011 at 13:46

Hi,

Clive1 is right... as usual 😉 I had the same problem few weeks ago and changed the initialization order given in the example. The ''array swapping values'' phenomenon disappeared.

[mrost9]

Posted on May 17, 2011 at 13:46 By chance I just saw, that the problem occurs reliably when the STM resets itself. (Usually I turn power off and on, that's why I couldn't reproduce it.) So I guess, either ADC or DMA are not completely reset by my initialisation code. But shouldn't the periphereals not be reset by this code? <code> void ResetSTM32() {     SCB->AIRCR = 0x05FA0000 | SCB_AIRCR_VECTRESET;        // resets periphereals only     SCB->AIRCR = 0x05FA0000 | SCB_AIRCR_SYSRESETREQ;    // resets the core } </code> just wondering....EDIT: Confirmed. Adding ADC_DeInit(ADC1); before ADC_Init really helps.