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#include "audio.h"
#include "i2c.h"
#include "stm32f4xx_conf.h"
#include "stm32f4xx.h"
#include <stdlib.h>
static void WriteRegister(uint8_t address, uint8_t value);
static void StartAudioDMAAndRequestBuffers();
static void StopAudioDMA();
static AudioCallbackFunction *CallbackFunction;
static void *CallbackContext;
static int16_t * volatile NextBufferSamples;
static volatile int NextBufferLength;
static volatile int BufferNumber;
static volatile bool DMARunning;
void InitializeAudio(int plln, int pllr, int i2sdiv, int i2sodd) {
GPIO_InitTypeDef GPIO_InitStructure;
// Intitialize state.
CallbackFunction = NULL;
CallbackContext = NULL;
NextBufferSamples = NULL;
NextBufferLength = 0;
BufferNumber = 0;
DMARunning = false;
// Turn on peripherals.
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI3, ENABLE);
// Assume I2C is set up
// Configure reset pin.
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOD, &GPIO_InitStructure);
// Configure I2S MCK, SCK, SD pins.
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7 | GPIO_Pin_10 | GPIO_Pin_12;
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(GPIOC, &GPIO_InitStructure);
GPIO_PinAFConfig(GPIOC, GPIO_PinSource7, GPIO_AF_SPI3);
GPIO_PinAFConfig(GPIOC, GPIO_PinSource10, GPIO_AF_SPI3);
GPIO_PinAFConfig(GPIOC, GPIO_PinSource12, GPIO_AF_SPI3);
// Configure I2S WS pin.
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
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_SPI3);
// Reset the codec.
GPIO_ResetBits(GPIOD, GPIO_Pin_4);
for (volatile int i = 0; i < 0x4fff; i++) {
__asm__ volatile("nop");
}
GPIO_SetBits(GPIOD, GPIO_Pin_4);
// Configure codec.
WriteRegister(0x02, 0x01); // Keep codec powered off.
WriteRegister(0x04, 0xaf); // SPK always off and HP always on.
WriteRegister(0x05, 0x81); // Clock configuration: Auto detection.
WriteRegister(0x06, 0x04); // Set slave mode and Philips audio standard.
SetAudioVolume(0xff);
// Power on the codec.
WriteRegister(0x02, 0x9e);
// Configure codec for fast shutdown.
WriteRegister(0x0a, 0x00); // Disable the analog soft ramp.
WriteRegister(0x0e, 0x04); // Disable the digital soft ramp.
WriteRegister(0x27, 0x00); // Disable the limiter attack level.
WriteRegister(0x1f, 0x0f); // Adjust bass and treble levels.
WriteRegister(0x1a, 0x0a); // Adjust PCM volume level.
WriteRegister(0x1b, 0x0a);
// Disable I2S.
SPI3 ->I2SCFGR = 0;
// I2S clock configuration
RCC ->CFGR &= ~RCC_CFGR_I2SSRC; // PLLI2S clock used as I2S clock source.
RCC ->PLLI2SCFGR = (pllr << 28) | (plln << 6);
// Enable PLLI2S and wait until it is ready.
RCC ->CR |= RCC_CR_PLLI2SON;
while (!(RCC ->CR & RCC_CR_PLLI2SRDY ))
;
// Configure I2S.
SPI3 ->I2SPR = i2sdiv | (i2sodd << 8) | SPI_I2SPR_MCKOE;
SPI3 ->I2SCFGR = SPI_I2SCFGR_I2SMOD | SPI_I2SCFGR_I2SCFG_1
| SPI_I2SCFGR_I2SE; // Master transmitter, Phillips mode, 16 bit values, clock polarity low, enable.
}
void AudioOn() {
WriteRegister(0x02, 0x9e);
SPI3 ->I2SCFGR = SPI_I2SCFGR_I2SMOD | SPI_I2SCFGR_I2SCFG_1
| SPI_I2SCFGR_I2SE; // Master transmitter, Phillips mode, 16 bit values, clock polarity low, enable.
}
void AudioOff() {
WriteRegister(0x02, 0x9f);
SPI3 ->I2SCFGR = 0;
}
void SetAudioVolume(int volume) {
WriteRegister(0x20, (volume + 0x19) & 0xff);
WriteRegister(0x21, (volume + 0x19) & 0xff);
}
void OutputAudioSample(int16_t sample) {
while (!(SPI3 ->SR & SPI_SR_TXE ))
;
SPI3 ->DR = sample;
}
void OutputAudioSampleWithoutBlocking(int16_t sample) {
SPI3 ->DR = sample;
}
void PlayAudioWithCallback(AudioCallbackFunction *callback, void *context) {
StopAudioDMA();
NVIC_EnableIRQ(DMA1_Stream7_IRQn);
NVIC_SetPriority(DMA1_Stream7_IRQn, 5);
SPI3 ->CR2 |= SPI_CR2_TXDMAEN; // Enable I2S TX DMA request.
CallbackFunction = callback;
CallbackContext = context;
BufferNumber = 0;
if (CallbackFunction)
CallbackFunction(CallbackContext, BufferNumber);
}
void StopAudio() {
StopAudioDMA();
SPI3 ->CR2 &= ~SPI_CR2_TXDMAEN; // Disable I2S TX DMA request.
NVIC_DisableIRQ(DMA1_Stream7_IRQn);
CallbackFunction = NULL;
}
void ProvideAudioBuffer(void *samples, int numsamples) {
while (!ProvideAudioBufferWithoutBlocking(samples, numsamples))
__asm__ volatile ("wfi");
}
bool ProvideAudioBufferWithoutBlocking(void *samples, int numsamples) {
if (NextBufferSamples)
return false;
NVIC_DisableIRQ(DMA1_Stream7_IRQn);
NextBufferSamples = samples;
NextBufferLength = numsamples;
if (!DMARunning)
StartAudioDMAAndRequestBuffers();
NVIC_EnableIRQ(DMA1_Stream7_IRQn);
return true;
}
static void StartAudioDMAAndRequestBuffers() {
// Configure DMA stream.
DMA1_Stream7 ->CR = (0 * DMA_SxCR_CHSEL_0 ) | // Channel 0
(1 * DMA_SxCR_PL_0 ) | // Priority 1
(1 * DMA_SxCR_PSIZE_0 ) | // PSIZE = 16 bit
(1 * DMA_SxCR_MSIZE_0 ) | // MSIZE = 16 bit
DMA_SxCR_MINC | // Increase memory address
(1 * DMA_SxCR_DIR_0 ) | // Memory to peripheral
DMA_SxCR_TCIE; // Transfer complete interrupt
DMA1_Stream7 ->NDTR = NextBufferLength;
DMA1_Stream7 ->PAR = (uint32_t) &SPI3 ->DR;
DMA1_Stream7 ->M0AR = (uint32_t) NextBufferSamples;
DMA1_Stream7 ->FCR = DMA_SxFCR_DMDIS;
DMA1_Stream7 ->CR |= DMA_SxCR_EN;
// Update state.
NextBufferSamples = NULL;
BufferNumber ^= 1;
DMARunning = true;
// Invoke callback if it exists to queue up another buffer.
if (CallbackFunction)
CallbackFunction(CallbackContext, BufferNumber);
}
static void StopAudioDMA() {
DMA1_Stream7 ->CR &= ~DMA_SxCR_EN; // Disable DMA stream.
while (DMA1_Stream7 ->CR & DMA_SxCR_EN )
; // Wait for DMA stream to stop.
DMARunning = false;
}
void DMA1_Stream7_IRQHandler() {
DMA1 ->HIFCR |= DMA_HIFCR_CTCIF7; // Clear interrupt flag.
if (NextBufferSamples) {
StartAudioDMAAndRequestBuffers();
} else {
DMARunning = false;
}
}
// Warning: don't i2c_write call from IRQ handler !
static void WriteRegister(uint8_t address, uint8_t value)
{
const uint8_t device = 0x4a;
const uint8_t data[2] = {address, value};
i2c_transaction_start();
i2c_write(device, data, 2);
i2c_transaction_end();
}
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