Hi,
I am using MPC5744p and having trouble reading multi-channel ADC data with DMA. When only one channel is active, I can access the data with DMA without any problems but I have problem when I try to access multiple ADC channels with multiple DMA channels. While all values written to the buffer in ram are valid when single channel is active, this is not the case in multi-channel. I shared the DMA init function and related images.
Additionally, do you have any sample codes or any documents you can recommend for using hw triggered multi-channel DMA?
uint32_t adc_arr2[100];
uint32_t adc_arr1[100];
static void dmamux_init(volatile struct DMAMUX_tag *dma_mux_p, uint8_t dmamux_source, uint8_t dma_ch)
{
dma_mux_p->CHCFG[dma_ch].B.ENBL = 1;
dma_mux_p->CHCFG[dma_ch].B.SOURCE = dmamux_source;
dma_mux_p->CHCFG[dma_ch].B.TRIG = 0;
}
void dma_0_init(void)
{
// DMAMUX_1 configuration for ADC trigger
dmamux_init(&DMAMUX_1, 0xC, 1); //dma0 channel 17 init
dmamux_init(&DMAMUX_1, 0xC, 2); //dma0 channel 18 init
DMA_0.ERQ.B.ERQ17 = 1; //The DMA request signal for channel 17
DMA_0.ERQ.B.ERQ18 = 1; //The DMA request signal for channel 18
DMA_0.TCD[17].SADDR.R = ((vuint32_t) &ADC_1.CDR[1].R); //Source Address ADC1_AN[1]
DMA_0.TCD[17].ATTR.R = 0x0 | 0x200 | 0x0 | 0x2; //Source transfer size 32-bit, no Address Modulo used
DMA_0.TCD[17].SOFF.R = 0; // TCD Signed Source Address Offset(constant)
DMA_0.TCD[17].NBYTES.MLNO.R = 4; //Minor Byte Count: 4byte
DMA_0.TCD[17].SLAST.R = 0; //TCD Last Source Address Adjustment
DMA_0.TCD[17].DOFF.R = 4;
DMA_0.TCD[17].DADDR.R = (vuint32_t) &adc_arr2[0]; //Destination Address
DMA_0.TCD[17].CITER.ELINKNO.R = 100;
DMA_0.TCD[17].DLASTSGA.R = -400; // Destination last address adjustment -(4byte*100 element)
DMA_0.TCD[17].BITER.ELINKNO.R = 100;
DMA_0.TCD[17].CSR.B.INTMAJOR = 1;
DMA_0.TCD[17].CSR.B.DREQ = 1;
DMA_0.TCD[18].SADDR.R = ((vuint32_t) &ADC_1.CDR[2].R); //Source Address ADC1_AN[2]
DMA_0.TCD[18].ATTR.R = 0x0 | 0x200 | 0x0 | 0x2; //Source transfer size 32-bit, no Address Modulo used
DMA_0.TCD[18].SOFF.R = 0;
DMA_0.TCD[18].NBYTES.MLNO.R = 4;
DMA_0.TCD[18].SLAST.R = 0;
DMA_0.TCD[18].DOFF.R = 4;
DMA_0.TCD[18].DADDR.R = (vuint32_t) &adc_arr1[0]; //Destination Address
DMA_0.TCD[18].CITER.ELINKNO.R = 100;
DMA_0.TCD[18].DLASTSGA.R = -400; // Destination last address adjustment
DMA_0.TCD[18].BITER.ELINKNO.R = 100;
DMA_0.TCD[18].CSR.B.INTMAJOR = 1;
DMA_0.TCD[18].CSR.B.DREQ = 1;
DMA_0.CR.R = 0xC; //round robin is used
INTC_0.PSR[70].R = 0x801F; //set interrupt priority
INTC_0.PSR[71].R = 0x801F; //set interrupt priority
}
void dma_ch18_major_completed_isr(void)
{
//there is a breakpoint in here to see content of the array
DMA_0.ERQ.B.ERQ18 = 1;
DMA_0.INT.B.INT18 = 1;
}
void dma_ch17_major_completed_isr(void)
{
//there is a breakpoint in here to see content of the array
DMA_0.ERQ.B.ERQ17 = 1;
DMA_0.INT.B.INT17 = 1;
}
Hi, for result draining you have to use ADC DMA source. Your configuration is incorrect.
I am sorry, I have somehow overlooked it. This is actually right.
But you have another issue there - you cannot route one DMA source to multiple DMA channels.
Use one channel for both result readings, or two linked channels, or scatter-gather feature.
