GPIODMATriggerEnable example for DMA SPI transfer initiated by GPIO

Robin van Dijke

Other Parts Discussed in Thread: CC3200

I am currently experimenting with transferring data using SPI and DMA on a CC3200. This is currently working perfect, but I want to go a step further and initiate the transfer by a GPIO falling edge input signal. At this moment I am thinking of setting up an interrupt for the GPIO pin and when the interrupt is triggered setting up the DMA transfer using

uDMAChannelControlSet(UDMA_CH30_GSPI_RX, UDMA_SIZE_8 | UDMA_SRC_INC_NONE | UDMA_DST_INC_NONE | UDMA_ARB_1);
uDMAChannelTransferSet(UDMA_CH30_GSPI_RX, UDMA_MODE_BASIC, (void *)SPI_INPUT_REGISTER, &nullByte, spi_dma_word_count);

and the same for UDMA_CH31_GSPI_TX. Start the transfer by enabling the channel using

uDMAChannelEnable(UDMA_CH30_GSPI_RX);

Instead of initiating the transfer every time by this interrupt code I saw the function GPIODMATriggerEnable in the documentation. I did not find any example on the internet using this method. Can someone explain me if this makes it possible to initiate a uDMA transfer by a GPIO pin? And if so, can you provide me with some sample code or an explanation how this works and how to set this up?

Thanks!

over 9 years ago

0 made4engineering over 9 years ago

TI__Mastermind 27565 points

HI Robin,

I'm looking into this to see if we can find a better explanation.

Thanks,
Aaron

0 Robin van Dijke over 9 years ago in reply to made4engineering

Prodigy 40 points

Thanks Aaron, looking forward to your explanation.

0 made4engineering over 9 years ago in reply to Robin van Dijke

TI__Mastermind 27565 points

HI Robin,

Here's an example of transferring between 2 memory locations:

//
// Enable and configure uDMA
//
UDMAInit();

//
// Setup uDMA transfer on GPIO port A2 trigger
//
UDMASetupTransfer(UDMA_CH20_GPIOA2, UDMA_MODE_BASIC, 256,
UDMA_SIZE_8, UDMA_ARB_1024, ucSrc,
UDMA_SRC_INC_8, ucDst, UDMA_DST_INC_8);

//
// Set the trigger type
//
MAP_GPIOIntTypeSet(GPIOA2_BASE,GPIO_PIN_6,GPIO_RISING_EDGE);

//
// Enable DMA trigger for port GPIO A2
//
MAP_GPIODMATriggerEnable(GPIOA2_BASE);

-Regards,

Aaron

0 Robin van Dijke over 9 years ago in reply to made4engineering

Prodigy 40 points

This looks great and straightforward. I'm gonna try and implement it in my project soon. I'll let you know the outcome. Thanks so much!

0 Robin van Dijke over 9 years ago in reply to made4engineering

Prodigy 40 points

Hi Aaron,

I tried triggering the transfer using your suggestion but it doesn't seem to work yet for me.

    // enable uDMA peripheral
    PRCMPeripheralClkEnable(PRCM_UDMA, PRCM_RUN_MODE_CLK);
    PRCMPeripheralReset(PRCM_UDMA);

    // register software interrupt handler
    IntPrioritySet(INT_UDMA, INT_PRIORITY_LVL_1);
    uDMAIntRegister(UDMA_INT_SW, udma_software_interrupt_handler);
    
    // register error interrupt handler
    IntPrioritySet(INT_UDMAERR, INT_PRIORITY_LVL_1);
    uDMAIntRegister(UDMA_INT_ERR, udma_error_interrupt_handler);
    
    // enable uDMA
    uDMAEnable();
    
    // set control table
	static tDMAControlTable udma_control_table[UDMA_CONTROL_TABLE_SIZE] __attribute__((aligned(1024)));
    memset(udma_control_table, 0, sizeof(tDMAControlTable) * UDMA_CONTROL_TABLE_SIZE);
    uDMAControlBaseSet(udma_control_table);

    // set up SPI for DMA
    SPIIntRegister(SPI_BASE, spi_dma_interrupt_handler);
    SPIWordCountSet(SPI_BASE, word_count);
    
    SPIFIFOLevelSet(SPI_BASE, 1, 1);
    SPIFIFOEnable(SPI_BASE, SPI_RX_FIFO);
    SPIFIFOEnable(SPI_BASE, SPI_TX_FIFO);
    
    SPIDmaEnable(SPI_BASE, SPI_RX_DMA);
    SPIDmaEnable(SPI_BASE, SPI_TX_DMA);
    
    SPIIntEnable(SPI_BASE, SPI_INT_EOW);

    // enable PIN_50 (pin 44 on chip) for GPIO Input
    PRCMPeripheralClkEnable(PRCM_GPIOA0, PRCM_RUN_MODE_CLK);
    PinModeSet(PIN_50, PIN_MODE_0);
    GPIODirModeSet(GPIOA0_BASE, 0x01, GPIO_DIR_MODE_IN);

    // enable burst
    uDMAChannelAttributeEnable(UDMA_CH30_GSPI_RX, UDMA_ATTR_USEBURST);
    uDMAChannelAttributeEnable(UDMA_CH31_GSPI_TX, UDMA_ATTR_USEBURST);
    
    // setup transfer for receiving data
    uDMAChannelControlSet(UDMA_CH30_GSPI_RX, UDMA_SIZE_8 | UDMA_SRC_INC_NONE | UDMA_DST_INC_8 | UDMA_ARB_1);
    uDMAChannelTransferSet(UDMA_CH30_GSPI_RX, UDMA_MODE_BASIC, (void *)SPI_BASE + MCSPI_O_RX0, output, 27);

    // setup transfer for transmitting data
    uDMAChannelControlSet(UDMA_CH31_GSPI_TX, UDMA_SIZE_8 | UDMA_SRC_INC_8 | UDMA_DST_INC_NONE | UDMA_ARB_1);
    uDMAChannelTransferSet(UDMA_CH31_GSPI_TX, UDMA_MODE_BASIC, input, (void *)SPI_BASE + MCSPI_O_TX0, 27);
        
    // start transferring
//    uDMAChannelEnable(UDMA_CH30_GSPI_RX);
//    uDMAChannelEnable(UDMA_CH31_GSPI_TX);

    // start transferring on trigger
    GPIOIntTypeSet(GPIOA0_BASE, GPIO_PIN_0, GPIO_FALLING_EDGE);
    GPIODMATriggerEnable(GPIOA0_BASE);

Before I just enabled the channels using `uDMAChannelEnable`. Instead, I now register GPIOA0_BASE as the trigger. When I trigger a falling edge transition (from 3.3v to GND on pin GPIOA0 / Pin 0) no DMA transfer seems to occur (my spi_dma_interrupt_handler function is not called). When I just enable the channel using `uDMAChannelEnable` everything works fine.

Do I have to set up the GPIOA0_BASE trigger in some order way?

Thanks!

Robin

0 made4engineering over 9 years ago in reply to Robin van Dijke

TI__Mastermind 27565 points

Hi Robin,

You still need to enable the channel, only with the GPIO

-Aaron

Wi-Fi

Wi-Fi forum

GPIODMATriggerEnable example for DMA SPI transfer initiated by GPIO