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External Codec vs Onboard Codec Configuration Differences STM32F4

epalaima
Associate II

‎2016-07-26 02:07 PM

Posted on July 26, 2016 at 23:07

I am trying to configure an external audio codec to work with the STM32F4 discovery board. I have got the onboard codec working via the spi driver (stm32f4xx_spi.c) and was wondering how I would have to configure things differently so that the data would be sent to the external codec instead. As is it seems like I could connect my external codec to the necessary GPIO pins, but the internal codec would be connected to these as well which would cause problems. Is it a matter of simply changing the GPIO pins, or would there be something more? 

I use the following 2 methods to initialize codec control in my program:

void codec_init()

{

GPIO_InitTypeDef PinInitStruct;

GPIO_StructInit(&PinInitStruct);

I2S_InitTypeDef I2S_InitType;

I2C_InitTypeDef I2C_InitType;

//Reset pin as GPIO

PinInitStruct.GPIO_Pin = CODEC_RESET_PIN;

PinInitStruct.GPIO_Mode = GPIO_Mode_OUT;

PinInitStruct.GPIO_PuPd = GPIO_PuPd_DOWN;

PinInitStruct.GPIO_OType = GPIO_OType_PP;

PinInitStruct.GPIO_Speed = GPIO_Speed_50MHz;

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA | RCC_AHB1Periph_GPIOD | RCC_AHB1Periph_GPIOB, ENABLE);

GPIO_Init(GPIOD, &PinInitStruct);

// I2C pins

PinInitStruct.GPIO_Mode = GPIO_Mode_AF;

PinInitStruct.GPIO_OType = GPIO_OType_OD;

PinInitStruct.GPIO_Pin = I2C_SCL_PIN | I2C_SDA_PIN;

PinInitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;

PinInitStruct.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_Init(GPIOB, &PinInitStruct);

GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_I2C1);

GPIO_PinAFConfig(GPIOB, GPIO_PinSource9, GPIO_AF_I2C1);

//enable I2S and I2C clocks

//RCC_I2SCLKConfig(RCC_I2S2CLKSource_PLLI2S);

RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1 | RCC_APB1Periph_SPI3, ENABLE);

RCC_PLLI2SCmd(ENABLE);

// I2S pins

PinInitStruct.GPIO_OType = GPIO_OType_PP;

PinInitStruct.GPIO_Pin = I2S3_SCLK_PIN | I2S3_SD_PIN | I2S3_MCLK_PIN;

GPIO_Init(GPIOC, &PinInitStruct);

PinInitStruct.GPIO_Pin = I2S3_WS_PIN;

GPIO_Init(GPIOA, &PinInitStruct);

//prepare output ports for alternate function

GPIO_PinAFConfig(GPIOA, GPIO_PinSource4, GPIO_AF_SPI3);

GPIO_PinAFConfig(GPIOC, GPIO_PinSource7, GPIO_AF_SPI3);

GPIO_PinAFConfig(GPIOC, GPIO_PinSource10, GPIO_AF_SPI3);

GPIO_PinAFConfig(GPIOC, GPIO_PinSource12, GPIO_AF_SPI3);

//keep Codec off for now

GPIO_ResetBits(GPIOD, CODEC_RESET_PIN);

// configure I2S port

SPI_I2S_DeInit(CODEC_I2S);

I2S_InitType.I2S_AudioFreq = I2S_AudioFreq_48k;

I2S_InitType.I2S_MCLKOutput = I2S_MCLKOutput_Enable;

I2S_InitType.I2S_DataFormat = I2S_DataFormat_16b;

I2S_InitType.I2S_Mode = I2S_Mode_MasterTx;

I2S_InitType.I2S_Standard = I2S_Standard_Phillips;

I2S_InitType.I2S_CPOL = I2S_CPOL_Low;

I2S_Init(CODEC_I2S, &I2S_InitType);

//I2S_Cmd(CODEC_I2S, ENABLE);

// configure I2C port

I2C_DeInit(CODEC_I2C);

I2C_InitType.I2C_ClockSpeed = 100000;

I2C_InitType.I2C_Mode = I2C_Mode_I2C;

I2C_InitType.I2C_OwnAddress1 = CORE_I2C_ADDRESS;

I2C_InitType.I2C_Ack = I2C_Ack_Enable;

I2C_InitType.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;

I2C_InitType.I2C_DutyCycle = I2C_DutyCycle_2;

I2C_Cmd(CODEC_I2C, ENABLE);

I2C_Init(CODEC_I2C, &I2C_InitType);

}

void codec_ctrl_init()

{

uint32_t delaycount;

uint8_t CodecCommandBuffer[5];

uint8_t regValue = 0xFF;

GPIO_SetBits(GPIOD, CODEC_RESET_PIN);

delaycount = 1000000;

while (delaycount > 0)

{

delaycount--;

}

//keep codec OFF

CodecCommandBuffer[0] = CODEC_MAP_PLAYBACK_CTRL1;

CodecCommandBuffer[1] = 0x01;

send_codec_ctrl(CodecCommandBuffer, 2);

//begin initialization sequence (p. 32)

CodecCommandBuffer[0] = 0x00;

CodecCommandBuffer[1] = 0x99;

send_codec_ctrl(CodecCommandBuffer, 2);

CodecCommandBuffer[0] = 0x47;

CodecCommandBuffer[1] = 0x80;

send_codec_ctrl(CodecCommandBuffer, 2);

regValue = read_codec_register(0x32);

CodecCommandBuffer[0] = 0x32;

CodecCommandBuffer[1] = regValue | 0x80;

send_codec_ctrl(CodecCommandBuffer, 2);

regValue = read_codec_register(0x32);

CodecCommandBuffer[0] = 0x32;

CodecCommandBuffer[1] = regValue & (~0x80);

send_codec_ctrl(CodecCommandBuffer, 2);

CodecCommandBuffer[0] = 0x00;

CodecCommandBuffer[1] = 0x00;

send_codec_ctrl(CodecCommandBuffer, 2);

//end of initialization sequence

CodecCommandBuffer[0] = CODEC_MAP_PWR_CTRL2;

CodecCommandBuffer[1] = 0xAF;

send_codec_ctrl(CodecCommandBuffer, 2);

CodecCommandBuffer[0] = CODEC_MAP_PLAYBACK_CTRL1;

CodecCommandBuffer[1] = 0x70;

send_codec_ctrl(CodecCommandBuffer, 2);

CodecCommandBuffer[0] = CODEC_MAP_CLK_CTRL;

CodecCommandBuffer[1] = 0x81; //auto detect clock

send_codec_ctrl(CodecCommandBuffer, 2);

CodecCommandBuffer[0] = CODEC_MAP_IF_CTRL1;

CodecCommandBuffer[1] = 0x07;

send_codec_ctrl(CodecCommandBuffer, 2);

CodecCommandBuffer[0] = 0x0A;

CodecCommandBuffer[1] = 0x00;

send_codec_ctrl(CodecCommandBuffer, 2);

CodecCommandBuffer[0] = 0x27;

CodecCommandBuffer[1] = 0x00;

send_codec_ctrl(CodecCommandBuffer, 2);

CodecCommandBuffer[0] = 0x1A | CODEC_MAPBYTE_INC;

CodecCommandBuffer[1] = 0x0A;

CodecCommandBuffer[2] = 0x0A;

send_codec_ctrl(CodecCommandBuffer, 3);

CodecCommandBuffer[0] = 0x1F;

CodecCommandBuffer[1] = 0x0F;

send_codec_ctrl(CodecCommandBuffer, 2);

CodecCommandBuffer[0] = CODEC_MAP_PWR_CTRL1;

CodecCommandBuffer[1] = 0x9E;

send_codec_ctrl(CodecCommandBuffer, 2);

}

#i2s #codec-audio #external #!stm32f4-disco
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