Posted on May 17, 2011 at 13:31Hello 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 ]
