uDMA to GPIO

Hello,

i look also for an example that triggers a udma burst with a timer. Data destination should be a gpio port...

My own source fails... :-/

I never was so much confused about a DMA implementation...

Thx

Basti

Hi Sebastian,

     As this post is more than a year ago, it would be much better to create a new post for your question. Indicate relevant details. See, below. 

     Information to provide when asking for help

     You, can also review the udma_demo example program at Tivaware.

-kel     

Hello Sebastian,

Do you have a code already implemented? If yes, then we can review and see why it does not work/

Regards

Amit

Here is my code... I call setup_dma before setup_timer:

void setup_dma()
{
	SysCtlPeripheralEnable(SYSCTL_PERIPH_UDMA);
	//SysCtlPeripheralSleepEnable(SYSCTL_PERIPH_UDMA);
	SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOE);

	GPIOPinTypeGPIOOutput(GPIO_PORTE_BASE, 0xFFFFFFFF);


	IntEnable(INT_UDMAERR);


	uDMAEnable();

    IntEnable(INT_UDMA);

    // Point at the control table to use for channel control structures.
    //
	uDMAControlBaseSet(pui8ControlTable);

	uDMAChannelAssign(UDMA_CH18_TIMER1A);

	uDMAChannelAttributeDisable(UDMA_CHANNEL_TMR1A,
	                                    UDMA_ATTR_ALTSELECT | UDMA_ATTR_USEBURST |
	                                    UDMA_ATTR_HIGH_PRIORITY |
	                                    UDMA_ATTR_REQMASK);

	uDMAChannelControlSet(UDMA_CHANNEL_TMR1A | UDMA_PRI_SELECT,
	                              UDMA_SIZE_8 | UDMA_SRC_INC_8 |
	                              UDMA_DST_INC_NONE |
	                              UDMA_ARB_1);

	uDMAChannelTransferSet(UDMA_CHANNEL_TMR1A | UDMA_PRI_SELECT,
	                               UDMA_MODE_BASIC, image_A,
	                               (void *)(GPIO_PORTE_AHB_DATA_R),
	                               1023);



	uDMAChannelEnable(UDMA_CHANNEL_TMR1A);
}


void setup_timer()
{
	SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER1);

	SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD);

	GPIOPinConfigure(GPIO_PD2_T1CCP0);

	GPIOPinTypeTimer(GPIO_PORTD_BASE,GPIO_PIN_2);

	//
	// Configure the two 32-bit periodic timers.
	//
	TimerConfigure(TIMER1_BASE, TIMER_CFG_PERIODIC | TIMER_CFG_SPLIT_PAIR | TIMER_CFG_A_PWM |TIMER_CFG_B_PWM);
	
	TimerLoadSet(TIMER1_BASE, TIMER_BOTH, 5);
	TimerMatchSet(TIMER1_BASE,TIMER_A,2);
	TimerMatchSet(TIMER1_BASE,TIMER_B,1);


	TimerDMAEventSet(TIMER1_BASE,TIMER_DMA_MODEMATCH_A);

	//TimerIntEnable(TIMER1_BASE,TIMER_TIMA_MATCH);
	TimerIntEnable(TIMER1_BASE,TIMER_TIMA_DMA);

	//
	// Setup the interrupts for the timer timeouts.
	//
	IntEnable(INT_TIMER1A);

	//
	// Enable the timers.
	//
	TimerEnable(TIMER1_BASE, TIMER_BOTH);
}

Hello Sebastien,

In the uDMAChannelControlSet the Destination Size is not mentioned. Though it defaults to 8 but it is an SRAM location so would be better that it does not remain uninitialized

Secondly, the uDMA takes time for processing a request. By keeping the timer match to a small value, it would cause a lot of trigger.

lastly the uDMA interrupt will be triggered on the GPT Interrupt line. I do not see a Timer Interrupt routine. Could you confirm the same?

Regards

Amit

Hello,

thx for your help... but for me it's already unclear... =(

1. I don't understand, sorry. 

2. Sure, but it seems my problem is that no request is send to the DMA Channel... Request will saved until 2 are reached... the 3rd will delete... is it to fast, it should also work?! Should I use UDMA_MODE_AUTO instead BASIC?

3. I have a Interrupt Routine but it gets never called:

void MyTimerInterrupt1A(void)
{

    uDMAChannelEnable(UDMA_CHANNEL_TMR1A);

    TimerIntClear(TIMER1_BASE,TIMER_TIMA_MATCH);

    GPIO_PORTN_DATA_R ^= 0x01;
}

Regards

Basti

Hello Sebastien,

1. Is the clock to GPIO Port A enabled in the code?

2. The TM4C123 GPIO is mapped to APB bus by default whereas you are using AHB Address Space.

Regards

Amit

I use just Port D for compare action, Port E for the destination of the Data and Port N for LED indication... 

Why should I activate Port A?

2. GPIO_PORTE_AHB_DATA_R = image_A[a][pwm_c]; does work correctly...

I think the destination address isn't the Problem...

I have tried also another timer (0A) and different DMA options... my interrupt routine gets now called... but the DMA transfer is never done :(

void MyTimerInterrupt0A(void)
{

	//uDMAChannelDisable(UDMA_CHANNEL_TMR0A);




	/*uDMAChannelTransferSet(UDMA_CHANNEL_TMR0A | UDMA_PRI_SELECT,
		                               UDMA_MODE_BASIC, &image_A[dma_counter],
		                               (void *)(GPIO_PORTE_AHB_DATA_R),
		                               192);*/


	mode = uDMAChannelModeGet(UDMA_CHANNEL_TMR0A | UDMA_PRI_SELECT);

	if(mode == UDMA_MODE_STOP)
	{
	    uDMAChannelEnable(UDMA_CHANNEL_TMR0A);

		dma_counter += 192;

		if(dma_counter >= (256*256))
			dma_counter = 0;

	    GPIO_PORTN_DATA_R ^= 0x01;
	}


    //TimerIntClear(TIMER0_BASE,TIMER_TIMA_DMA);
    TimerIntClear(TIMER0_BASE,0xFFFFFFFF);
}

For correction: I would like to set a complete byte to a port (E for example) time sync with a timer. I hope after all bytes clocked out to the port, the interrupt routine from the timer gets called and I can calculate the new source address...

But I stuck a lot and there is no much help out there :(

Thx Basti

Hello Sebastian,

Can you zip the CCS project. It would be easier for me to look at the full code, to analyze the issue.

Regards

Amit

Hello Amit,

thanks for your help... here is the project...

I have notice that the dma error interrupt gets called... but i don't know why... :(

5126.blinky.rar

Hello Sebastian

My suspicion is on GPIO_PORTE_AHB_DATA_R

Can you replace it with (void *)(GPIO_PORTE_AHB_DATA_R)  with just GPIO_PORTE_DATA, while I build it in my setup

Regards

Amit

sorry, I can't find a header file for this macro... where is it defined?

thx a lot

Amit Ashara said:

GPIO_PORTE_AHB_DATA_R

@Sebastian are you referring to this above. That  can be found at #include "inc/tm4c1294ncpdt.h"

-kel

Hello Sebastian

Are you using a TM4C129 device? If that is the case then I need to go through the whole code as the uDMA has some changes for TM4C129 in terms of Interrupt Vector.

Will post an update later.

Regards

Amit

I use the tiva launchpad with the ethernet functionality and yes it's an TM4C1294 Rev. B (for erreta)

@markel sorry I look for the other macro: GPIO_PORTE_DATA

Hello Sebastian

There are two issues

1. The Destination Address is pointer and I had to replace it with Actual Address of the Data Port

        uDMAChannelTransferSet(UDMA_CHANNEL_TMR0A | UDMA_PRI_SELECT,
                                               UDMA_MODE_BASIC, &image_A[dma_counter],
                                               (GPIO_PORTE_AHB_BASE+0x400),
                                               192);
2. It runs properly but the ImageA address computed goes above 256KB SRAM address space causing another Fault. You may want to check how to optimize this

Regards

Amit

Hello Amit,

+0x400 is the DIR Address Space...

The Data Space has a 256 byte space... because of this "feature":

"To aid in the efficiency of software, the GPIO ports allow for the modification of individual bits in the

GPIO Data (GPIODATA) register (see page 753) by using bits [9:2] of the address bus as a mask.

....

To implement this
feature, the GPIODATA register covers 256 locations in the memory map."

How can I direct control the PINs with a DMA?

Regards

Basti

Hello Sebastian

My bad!! It is 0x3FC and not 0x400. Doing the same with DMA is going to be complicated and I would rather do a CPU method than DMA for such a requirement.

Regards

Amit

Ahhhhhhhhhhhh...

Okay, I have it...

&GPIO_PORTE_AHB_DATA_R == GPIO_PORTE_AHB_BASE+0x3FC

Now I seems to work...

DMA is required... CPU has to calculate the the PWM to the SRAM from the image... 

Thank you for your great help!