PROBLEM WITH PERIPHERAL POST-INCREMENT USING DMA - STM32F100VC

[FTrnp]

Hi,

I am using DMA to transfer the conversion of two injected channels of the ADC module (registers ADC1_JDR1 & ADC1_JDR2) to a buffer in ram. The conversion is started by software (JSWSTART).

Since the transfer is for two consecutive records, I have set the following configuration:

DMA1_CCR1:

MINC = 1

PINC = 1

DIR = 0

EN = 1

DMA1_CNDTR1 = 2

DMA1_CPAR1 = &ADC1_JDR1

DMA1 _CMAR1 = &buffer_ram

Unexpectedly only the record ADC1_JDR1 is transferred, although Number of Data Transfer is 2.

Only for test purposes I have changed PINC = 0 and then the record ADC1_JDR1 is transferred 2 times, as expected.

What is wrong ??

[waclawek.jan]

In the case of PINC=1, what exactly happens - you see content of ADC1_JDR1 in buffer_ram[0] and unchanged content of buffer_ram[1]? What is in the status bits of DMA?

JW

[FTrnp]

Yes,

with PINC=1:

buffer_ram[0] = ADC1_JDR1

buffer_ram[1] = Unchanged

with PINC=0

buffer_ram[0] = ADC1_JDR1

buffer_ram[1] = ADC1_JDR1

However, I have seen in the reference manual that only the conversion of the regular channels triggers dma !!!. Injected channels don't. Therefore, I don't know what I was seeing.

I have changed the software to use the end-of-conversion interrupt (JEOC) and it works fine.

Thanks for the reply.

[waclawek.jan]

Thanks for the info.

JW