Kinetis MicrocontrollersのトピックRe: PIT->PDB->DMA

PIT->PDB->DMA

ishwarlal — Mon, 28 Aug 2017 09:01:09 GMT

Hi,

We are using MK66 with a custom board, AtollicTs no sdk (custom code) .

I am looking for an example to for PDB to trigger DMA transfer. There is a lot of discussion related ADC trigger DMA and PIT trigger DMA and PDB trigger ADC in forum but no post related to PDB trigger DMA.

Actually I want to trigger DMA_CH0 & DMA_CH3 with PIT0 the first part is easy PIT0 is internally connected to DMA_CH0 but the second part is tricky, I tried it myself but no success. the first part is working (i-e PIT0 trigger DMA_CH0) but the second part is not working (i-e PIT0->PDB->DMA_CH3). My all other PIT channels are already used for other tasks.

Dose anyone know have experience with PDB DMA trigger?

Regards

Lal

Re: PIT->PDB->DMA

ishwarlal — Mon, 28 Aug 2017 10:10:27 GMT

Ok I solved the problem it was due to IDLY register, the IDLY is set to 0xFFFF by default and this is to large in my case, I simply set it to 0 and it works.

Here is the PDB code:

Regards

Lal

Re: PIT->PDB->DMA

ishwarlal — Mon, 28 Aug 2017 11:41:00 GMT

In case someone also need the DMA code, here it is:

volatile DMA_Type* m_pDma = DMA0;
const uint8_t m_Ch = 3;
uint16_t SrcDataBuff[2];
uint16_t DestData;

void Init_Dma()
{
   //Enable clocks
   SIM_SCGC6 |= SIM_SCGC6_DMAMUX_MASK;
   SIM_SCGC7 |= SIM_SCGC7_DMA_MASK;

   //Here put correct source and destination address parameters.
   m_pDma->TCD[m_Ch].SADDR =   SrcDataBuff; //Source address
   m_pDma->TCD[m_Ch].SOFF =   2;           //Source offset
   m_pDma->TCD[m_Ch].SLAST = -4;           //Source final address adjustment.

   m_pDma->TCD[m_Ch].DADDR     = &DestData; //destination address
   m_pDma->TCD[m_Ch].DOFF      = 0;
   m_pDma->TCD[m_Ch].DLAST_SGA = 0;

//number of bytes to transfer per dma request
m_pDma->TCD[m_Ch].NBYTES_MLNO = 2;

   //Dma major iteration count
   m_pDma->TCD[m_Ch].BITER_ELINKYES |= DMA_BITER_ELINKYES_BITER(2); //2 iterations
   m_pDma->TCD[m_Ch].CITER_ELINKYES = m_pDma->TCD[m_Ch].BITER_ELINKYES

   //Enable hardware trigger so that PDB can trigger DMA
   m_pDma->SERQ = m_Ch;   //enable hw triggering.
   DMAMUX->CHCFG[m_Ch] = 0;
   DMAMUX->CHCFG[m_Ch] = DMAMUX_CHCFG_ENBL(1) | DMAMUX_CHCFG_SOURCE(48); //Select PDB as hw trigger source.

//at this point you may enable DMA Interrupt.
}