MQX and DMA

SortoVaritu — Thu, 22 Nov 2012 19:14:42 GMT

Hello!

I would like to use DMA in my MQX application. Is it possible? MQX driver for DMA is not released yet. Can i use DMA throe configuration of registers?

Maybe somebody can share an example...

Re: MQX and DMA

c0170 — Thu, 29 Oct 2020 09:35:47 GMT

Hello Rozbergn,

please don't duplicate posts. I removed previous one and I'll add it here what was there:

In my application i need to collect information from ADC every 200us during 2 sec.

I would like to use DMA for this. Collect data in RAM and after save this information on SD card.

Anyone have such example or have another idea how to do this measurement?

Regards,

MartinK

Re: MQX and DMA

juanandujar — Mon, 02 Jun 2014 09:35:42 GMT

Hello,

I am trying to set up the ADC1 (software trigger) with DMA tranfer. The issue is that the dma does not work properly. Bellow I show how the adc1 register is configurated:

As it can be seen, the register ADC1_RA is working and the DMAEN is enabled. Bellow I show how the dma code:

/*DMA MUX initialization*/

SIM_SCGC6 |= SIM_SCGC6_DMAMUX0_MASK | SIM_SCGC6_DMAMUX1_MASK; //enables DMA MUX clock gate

/*eDMA module initialization*/

SIM_SCGC7 |= SIM_SCGC7_DMA_MASK;//enables DMA clock gate, default value is enable

//***************************************************************

//**** DMA transfer request source – ADC0 conversion complete

//***************************************************************

DMAMUX0_CHCFG1 = 0

| DMAMUX_CHCFG_ENBL_MASK /* Enable routing of DMA request */

| DMAMUX_CHCFG_SOURCE(40); /* Channel Activation Source: AD_A Command */

DMA_CR = DMA_CR_GRP1PRI(0x00) |

DMA_CR_GRP0PRI(0x00) |

DMA_CR_EMLM_MASK |

DMA_CR_CLM_MASK |

DMA_CR_ERGA_MASK |

DMA_CR_ERCA_MASK;

//enables DMA0 request

DMA_ERQ = 0x03;

//***************************************************************

//**** Source address, ADC0_RA

//***************************************************************

DMA_TCD1_SADDR = (uint32) &ADC1_RA;

//***************************************************************

//**** Source address increment; data is still read for the same address, no increment needed

//***************************************************************

DMA_TCD1_SOFF = 0x00;

//***************************************************************

//**** Source address reload after major loop finishes, no reload needed//***************************************************************

DMA_TCD1_SLAST = 0x00;

//***************************************************************

//**** Destination address, SRAM buffer [0]

//*************************************************************

DMA_TCD1_DADDR = (uint32)&Data_Desti[0];

//***************************************************************

//**** Destination address increment in bytes, increment for next buffer address

//**** 16 bit => 2 bytes

//***************************************************************

DMA_TCD1_DOFF = 0x02;

//***************************************************************

//**** Destination address reload after major loop finishes,

//**** must be subtracted from last pointer value, sample number is 12 each and 2 bytes long,

//**** 2 × 12 = 24 and must be subtract -24

//***************************************************************

DMA_TCD1_DLASTSGA = -24;

//***************************************************************

//**** Number of bytes for minor loop (one data transfer), ADC0 result is 16 bits long, so

//**** 2-byte transfer

//***************************************************************

DMA_TCD1_NBYTES_MLNO = 0x02;

//***************************************************************

//**** Channel linking and major loop setting, linking after minor loop is enabled to

//**** channel 0 (0x0000), major loop transfers number 12 (0x0C)

//***************************************************************

DMA_TCD1_BITER_ELINKNO = (DMA_BITER_ELINKNO_ELINK_MASK|0x0000|0x0C);

//***************************************************************

//**** Channel linking and major loop setting reload value after major loop finishes,

//**** linking after minor loop is enabled, major loop transfers number 12 (0x0C).

//***************************************************************

DMA_TCD1_CITER_ELINKNO = (DMA_CITER_ELINKNO_ELINK_MASK|0x0C);

//***************************************************************

//**** Source and destination data width specification, both source and destination is 16-bit

//***************************************************************

DMA_TCD1_ATTR = 0 | DMA_ATTR_SSIZE(1)| DMA_ATTR_DSIZE(1);

//***************************************************************

//**** Common channel setting, linking after major loop enable to channel 0,

//**** IRQ request is generated after major loop complete

//***************************************************************

DMA_TCD1_CSR = (DMA_CSR_MAJORLINKCH(0) |

DMA_CSR_MAJORELINK_MASK|

DMA_CSR_INTMAJOR_MASK);

Maybe somebody knows the mistake...

Cheers.

Re: MQX and DMA

Alice_Yang — Wed, 24 Sep 2014 03:09:24 GMT

Hello,

On ADC-DMA project , two points need to be pay attention: in ADC register enable DMA request (ADC0_SC2->DMAEN) and in DMA register enalbe peripheral request (DMA_DCR0->ERQ).

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