Posted on March 01, 2016 at 19:56So I am trying to output an I2S signal from a STM32F0 but although I believe I am initializing the peripheral correctly I am not getting any signal on the pins. I believe I am enabling the appropriate clocks and have the pin/DMA mapping correct based on the information I have. What am I missing? My code is as follows:
I2S_InitTypeDef I2S_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
DMA_InitTypeDef DMA_InitStructure;
audio[0] = 0x5555;
audio[1] = 0x0;
audio[2] = 0x5555;
audio[3] = 0x0;
audio[4] = 0x5555;
audio[5] = 0xffff;
audio[6] = 0xffff;
audio[7] = 0xffff;
audio[8] = 0xffff;
audio[9] = 0xffff;
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4 | GPIO_Pin_5 | GPIO_Pin_7;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStructure);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource4, GPIO_AF_0); // I2S1 WS (word select)
GPIO_PinAFConfig(GPIOA, GPIO_PinSource5, GPIO_AF_0); // I2S1 CK (serial clock)
GPIO_PinAFConfig(GPIOA, GPIO_PinSource7, GPIO_AF_0); // I2S1 SD (serial data)
// I2S1 peripheral configuration
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
I2S_InitStructure.I2S_Standard = I2S_Standard_Phillips;
I2S_InitStructure.I2S_DataFormat = I2S_DataFormat_16b;//32b;//24b;
I2S_InitStructure.I2S_AudioFreq = I2S_AudioFreq_8k;
I2S_InitStructure.I2S_CPOL = I2S_CPOL_Low;
I2S_InitStructure.I2S_MCLKOutput = I2S_MCLKOutput_Enable;//Disable;//
I2S_InitStructure.I2S_Mode = I2S_Mode_MasterTx;
I2S_Init(SPI1, &I2S_InitStructure);
// DMA configuration for audio streaming
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&SPI1->DR; // SPI data register for sending
DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)audio;
DMA_InitStructure.DMA_BufferSize = 10;
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_Circular;
DMA_InitStructure.DMA_Priority = DMA_Priority_High;
DMA_Init(DMA1_Channel3, &DMA_InitStructure);
SPI_I2S_DMACmd(SPI1, SPI_I2S_DMAReq_Tx, ENABLE);
DMA_Cmd(DMA1_Channel3, ENABLE); // Enable/Disable DMA
I2S_Cmd(SPI1, ENABLE);
