ADC1 converts only 1st channel of regular group

[jbolting9]

Posted on January 14, 2010 at 16:38

ADC1 converts only 1st channel of regular group

[disirio]

Posted on May 17, 2011 at 13:31

Hello,

I just wrote an ADC driver using DMA and it appears to work correctly in the scenario you described. The code is here:

http://chibios.svn.sourceforge.net/viewvc/chibios/trunk/os/hal/platforms/STM32/

Look for adc_lld.c and adc_lld.h, I hope this can help.

regards,

Giovanni

---

ChibiOS/RT

http://chibios.sourceforge.net

[jbolting9]

Posted on May 17, 2011 at 13:31

Hello everyone,

using the ADC1 in combination with DMA I encountered the following problem:

ADC1 is configured to convert a group of 5 different regular channels; continuous mode as well as scan modes is enabled. DMA1 is configured to transfer the results from the ADC1_DR (data register) to an array defined as u16 buffer[5]. The content of the array is sent to PC by USART2.

Unfortunately all 5 values in the buffer array seem to be conversion results of the first channel of the regular group. Any guess?

my code:

--------------ADC1 configuration-

void ADC1_Start_ConvGroup_1(u32 buffer_startaddress, u8 buffer_length_absolute) //starts continuous conversion of a group of regular channels; results are stored in buffer by DMA

{

ADC1_CR2 &= ~BIT1; //clear END OF CONVERSION bit

DMA1_Ch1_SetTargetAddress(buffer_startaddress, (u16) buffer_length_absolute); //give start address of ADC1 conversion results buffer to DMA1

ADC1_SQR3 |= (BIT1 | BIT2 | BIT3); //select channel 14 as first one to convert in regular conversion

//ADC1_SQR3 |= (BIT1 | BIT3); //set channel 10 as first one to convert in regular conversion

ADC1_SQR3 |= (BIT5 | BIT6 | BIT8); //set channel 11 as second one to convert

ADC1_SQR3 |= (BIT12 | BIT13); //set channel 12 as third one to convert

ADC1_SQR3 |= (BIT15 | BIT17 | BIT18); //set channel 13 as fourth one to convert

ADC1_SQR3 |= (BIT21 | BIT22 | BIT23); //set channel 14 as fifth one to convert

ADC1_SQR1 |= (BIT20 | BIT22); //set length of group of channels to convert to 5

ADC1_CR2 |= BIT8; //enable DMA mode

ADC1_CR1 |= BIT8; //enable scan mode

ADC1_CR2 |= BIT1; //enable continuous mode

return;

}

----------------DMA configuration-------

void DMA1_Init_Ch1(void)

{

/*Configure DMA1 channel 1 for ADC1*/

DMA1_CPAR1 = (u32)(ADC1_BASE + 0x4C); //set the ADC1 Data register as source for DMA transfers

DMA1_CCR1 = 0; //set to default

DMA1_CCR1 |= BIT13; //set channel priority bits to 10=''high''

DMA1_CCR1 |= BIT10; //set Memory Size to 16 bit

DMA1_CCR1 |= BIT8; //set Peripheral memory size to 16 bit

DMA1_CCR1 |= BIT7; //enable memory increment mode

DMA1_CCR1 |= BIT5; //enable circular mode

//DMA1_CCR1 |= BIT4; //data transfer direction: read from memory

//DMA1_CNDTR1 = 5; //number of data to be transmitted; afterwards, DMA1_CNDTR7 is reloaded with this value if circular mode is enabled

//DMA1_CCR1 |= BIT0; //enable channel

return;

}

void DMA1_Ch1_SetTargetAddress(u32 address, u16 nod)

{

DMA1_CCR1 &= ~BIT0; //disable channel: reset bit 0

DMA1_CMAR1 = address; //set memory address to where the DMA will transfer data from the ADC1_DATA register

DMA1_CNDTR1 = nod; //set number of data to transfer by DMA

DMA1_CCR1 |= BIT0; //enable channel

}

best regards,

Jan

[ This message was edited by: j.bolting on 26-11-2009 22:53 ]

[ This message was edited by: j.bolting on 26-11-2009 22:55 ]

[jbolting9]

Posted on May 17, 2011 at 13:32

Hi,

o.k., sorry, that was my fault. Obviously it was a mistake in the wiring on my testboard. Now everything works fine.

best regards,

jan

[ This message was edited by: j.bolting on 14-01-2010 21:09 ]

[ This message was edited by: j.bolting on 14-01-2010 21:10 ]