I made a vga signal, trough the spi as pixel sending, can you suggest a faster op?

[angeliran]

I use this:

void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef * htim)

{

if (htim->Instance==TIM2) // Tarda 2.17 us en llegar aqui, AQUI DIBUJO EL BUFFER, EN HSYNC

{

if((m<56))

{

for (h=0;h<16;h++){} //10 ORIG, AQUI DAMOS ESPACIO PARA FONT PORCH

HAL_SPI_Transmit_DMA_MIA(&hspi1,pointer_Data,Data_size);

pointer_Data[0]=fb[m][0];  

pointer_Data[1]=fb[m][1];

pointer_Data[2]=fb[m][2];

.......

m++;

Where my function is:

void HAL_SPI_Transmit_DMA_MIA(SPI_HandleTypeDef *hspi, uint8_t *pData, uint16_t Size)

{ /*  

 HAL_StatusTypeDef errorcode = HAL_OK;

 assert_param(IS_SPI_DIRECTION_2LINES_OR_1LINE(hspi->Init.Direction));

 */

 hspi->pTxBuffPtr = pData;

 hspi->TxXferSize = Size;

 hspi->TxXferCount = Size;/*

 hspi->pRxBuffPtr = (uint8_t*)NULL;

 hspi->RxXferSize = 0;

 hspi->RxXferCount = 0;*/

 /* Enable the Tx DMA channel */

 HAL_DMA_Start_IT(hspi->hdmatx, (uint32_t)hspi->pTxBuffPtr, (uint32_t)&hspi->Instance->DR, hspi->TxXferCount);

 /* Check if the SPI is already enabled */

 // if((hspi->Instance->CR1 &SPI_CR1_SPE) != SPI_CR1_SPE)

 //{

  /* Enable SPI peripheral */   

  __HAL_SPI_ENABLE(hspi);

 // }

 /* Enable Tx DMA Request */

 SET_BIT(hspi->Instance->CR2, SPI_CR2_TXDMAEN);

}

[KnarfB]

Copying the pixels from fb row m to pointer_Data seems time consuming and should be avoided.

> can you suggest a faster op

Where else do you see room for improvements?

hth

KnarfB

[angeliran]

Thx for answer me @KnarfB​ ! =(. In some examples I've seen, they use something like:

 SET_BIT(hspi->Instance->CR2, SPI_CR2_TXDMAEN);

And with only one instruction they begin to draw, but they uses standard libraries, i'm using hal libraries...

[Tesla DeLorean]

The MCU and the underlying registers and bits, are the same between HAL and SPL implementations.

SPI2->CR2 will work on all CMSIS based implementations.

[angeliran]

It´s just an example, =(...

This is what artekit uses:

1. //*****************************************************************************
2. // This irq is generated at the end of the horizontal back porch.
3. // Test if inside a valid vertical start frame (vflag variable), 
4. // and start the DMA to output a single frame buffer line through the SPI device.
5. //*****************************************************************************
6. void TIM1_CC_IRQHandler(void)
7. {
8. if (vflag)
9. {
10. // VIDEO_DMA->LIFCR = 0x003d0000; // hard-coded clear of all DMA2 interrupt flags
11. DMA_STREAM->CR |= DMA_SxCR_EN; // set the EN bit to enable the stream
12. // LED_ON(RED); // debug
13. // LED_OFF(ORANGE); // debug
14. }
15. TIM1->SR &= ~TIM_IT_CC2; // 0xFFFB; //~TIM_IT_CC2;
16. }