STM32F407 I2S single DMA transfer size

michaelisaev9 · ‎2014-12-04

Posted on December 05, 2014 at 01:14

I need to make a single small TX transfer over I2S interface using DMA. But instead of short transfer I've got a long-long transfer (seems of maximum size). What is the right method to set the number of packets to be sent? Isn't it a DMA_BufferSize member? Here is my code:

void I2S_Config(void)

{

GPIO_InitTypeDef GPIO_InitStructure;

I2S_InitTypeDef I2S_Config;

DMA_InitTypeDef DMA_InitStructure;

/* I2S PCLK = 2Mhz * 200 / 2 = 200Mhz */

/* 2Mhz * N = <192-432> */

RCC_PLLI2SConfig(200, 2);

RCC_PLLI2SCmd(ENABLE);

/* Enable GPIOs clocks */

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);

/* Connect pins to AF ************************************************/

/* CLK and SD (TX)*/

GPIO_PinAFConfig(GPIOB, GPIO_PinSource13, GPIO_AF_SPI2);

GPIO_PinAFConfig(GPIOB, GPIO_PinSource15, GPIO_AF_SPI2);

/* GPIO configuration **************************************************/

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13 | GPIO_Pin_15;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;

GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;

GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;

GPIO_Init(GPIOB, &GPIO_InitStructure);

RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI2, ENABLE);

I2S_StructInit(&I2S_Config);

I2S_Config.I2S_AudioFreq = I2S_AudioFreq_Default;

I2S_Config.I2S_CPOL = I2S_CPOL_Low;

I2S_Config.I2S_DataFormat = I2S_DataFormat_16b;

I2S_Config.I2S_MCLKOutput = I2S_MCLKOutput_Disable;

I2S_Config.I2S_Mode = I2S_Mode_MasterTx;

I2S_Config.I2S_Standard = I2S_Standard_Phillips;

I2S_Init(SPI2, &I2S_Config);

/* I2S CLK = I2S PCLK / 2 * DIV = 200 / 2 * DIV/

/* 200 / (2 * 50) = 2Mhz */

SPI2->I2SPR = 0x0000 + 50;

I2S_Cmd(SPI2, ENABLE);

/* Enable DMA1 clock */

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE);

/* DMA1 Stream4 Configuration */

DMA_DeInit(DMA1_Stream4);

DMA_InitStructure.DMA_Channel = DMA_Channel_0; // SPI

DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&(SPI2->DR);

DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)&MySYNCBuffer[0];

DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;

DMA_InitStructure.DMA_BufferSize = I2S_BUFFER_SIZE;

DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;

DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;

DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;

DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;

DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;

DMA_InitStructure.DMA_Priority = DMA_Priority_High;

DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;

DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_Full;

DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;

DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;

DMA_Init(DMA1_Stream4, &DMA_InitStructure);

DMA_FlowControllerConfig(DMA1_Stream4, DMA_FlowCtrl_Peripheral);

SPI_I2S_DMACmd(SPI2, SPI_I2S_DMAReq_Tx, ENABLE);

}

int main(void)

{

RCC_GetClocksFreq(&RCC_Clocks);

I2S_Config();

DMA_Cmd(DMA1_Stream4, ENABLE);

while (DMA_GetCmdStatus(DMA1_Stream4) == ENABLE);

while (SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_BSY) == SET);

while (1)

{

}

In this example I've got a million of packets instead of I2S_BUFFER_SIZE. Who knows what I am doing wrong?

#i2s #stm32f #dma

waclawek.jan · ‎2014-12-05

Posted on December 05, 2014 at 12:39

> DMA_FlowControllerConfig(DMA1_Stream4, DMA_FlowCtrl_Peripheral);

If this does what I believe it does (probably sets PFCTRL bit in DMA_SxCR - I don't speak the ''library'' gobbledygook), I know what do you do wrong: you don't read the manual.

RM0090 rev.8 ch.10.3.15 Flow controller

JW

michaelisaev9 · ‎2014-12-05

Posted on December 05, 2014 at 21:35

Jan, thank you very much ! It really helped. I also read AN4031 and wish ST include some parts of it in Reference Manual. AppNotes are more clear in understanding. I tried both values for FlowController and it seems ''Peripherial'' was the last when I end my experiments and posted code here. Some other parameters values makes my code non-working when FlowController had correct value.

Good luck!