KL27Z DMA from TPM2,CH0 CnV register causes bus error

jamescollier — Fri, 06 Oct 2017 13:57:43 GMT

I am using a Kinetis KL27Z prototyping board and KSDK 2.2.1 generated by MCUXpresso.

In the MCUXpresso pins tool I've enabled DMA channel 3 routed to the TPM2_CH0_Event. I've also enabled TPM2,0 on pin 37. On the board itself I have a signal generator attached to pin 37.

I've configured the TPM2,0 in input capture mode and set it to trigger DMA. I want to DMA the channel counter (CnV) register to a memory location but on the trigger the DMA BSE bit is set.

//TPM is initialised with:

TPM_Init(TPM2, &tpmConfig); //default config
TPM_SetupInputCapture(TPM2, kTPM_Chnl_0, kTPM_RiseAndFallEdge);
TPM2->SC |= TPM_SC_DMA_MASK;
TPM2->CONTROLS[0].CnSC |= TPM_CnSC_DMA_MASK;

//set the DMA source address

uint32_t cnv_reg = (uint32_t)&(TPM0->CONTROLS[kTPM_Chnl_0].CnV);

//Then DMA

DMAMUX_Init(DMAMUX0);

DMAMUX_SetSource(DMAMUX0, DMA_CHANNEL3_IDX, (uint8_t)kDmaRequestMux0TPM2Channel0);

DMA_Init(DMA0);

dma_handle_t dma_handle;
DMA_CreateHandle(&dma_handle, DMA0, 3U);

DMA_PrepareTransfer(&dma_config,
                                      (void*)cnv_reg, sizeof(uint32_t),
                                      &output_buffer, sizeof(uint32_t),
                                      0x4, kDMA_PeripheralToMemory);
DMA_SubmitTransfer(&dma_handle, &dma_config, kDMA_NoOptions);
DMA_EnableCycleSteal(DMA0, 3U, true);
DMA_StartTransfer(&dma_handle);

//Start the TPM timer

TPM_StartTimer(TPM2, kTPM_SystemClock);

//And finally wait for results (turn on the output of the signal generator manually)

PRINTF("TPM STATUS: 0x%x DMA_DSR_BCR: 0x%x\r", TPM2->STATUS, DMA0->DMA[3U].DSR_BCR);

//this results in "TPM STATUS: 0x101 DMA_DSR_BCR: 0x210ffffc" printed (note the BSE bit is set)

How can I avoid a bus error here?

Thanks very much for any help.

Re: KL27Z DMA from TPM2,CH0 CnV register causes bus error

mjbcswitzerland — Fri, 06 Oct 2017 15:17:12 GMT

James

What is cnv_reg? If the BES bit is set it would mean that this is an invalid address.

Regards

Mark

Re: KL27Z DMA from TPM2,CH0 CnV register causes bus error

jamescollier — Mon, 09 Oct 2017 13:06:55 GMT

I've edited the post to show what cnv_reg is.

Note that it now becomes obvious what the problem is: cnv_reg is pointing to TPM0, when TPM2 was initialised and intended for use.

Thanks for the help!

Kinetis MicrocontrollersのトピックKL27Z DMA from TPM2,CH0 CnV register causes bus error

KL27Z DMA from TPM2,CH0 CnV register causes bus error

Re: KL27Z DMA from TPM2,CH0 CnV register causes bus error

Re: KL27Z DMA from TPM2,CH0 CnV register causes bus error