void initClocks() {
// enable HSI and set it as the system clock source
RCC_HSICmd(ENABLE);
while(!(RCC->CR & RCC_CR_HSIRDY)); // wait for it to be ready
RCC_SYSCLKConfig(RCC_SYSCLKSource_HSI);
// disable PLL and PLLI2S
RCC_PLLCmd(DISABLE);
RCC_PLLI2SCmd(DISABLE);
// disable HSE and CSS (disabling the HSE also disables CSS)
RCC_HSEConfig(RCC_HSE_OFF);
// Configure PLL values and set source to HSE
RCC_PLLConfig(
RCC_PLLSource_HSE,
DESIRED_PLL_M,
DESIRED_PLL_N,
DESIRED_PLL_P,
DESIRED_PLL_Q
);
// set PLL I2S to our new values
RCC_PLLI2SConfig(
DESIRED_PLL_I2S_N,
DESIRED_PLL_I2S_R
);
// set I2S clock source to PLLI2S
RCC_I2SCLKConfig(RCC_I2S2CLKSource_PLLI2S);
// set AHB, APB1, APB2 prescalers
RCC_HCLKConfig(DESIRED_HCLK_DIV);
RCC_PCLK1Config(DESIRED_PCLK1_DIV);
RCC_PCLK2Config(DESIRED_PCKL2_DIV);
// enable HSE
RCC_HSEConfig(RCC_HSE_ON);
if(RCC_WaitForHSEStartUp() == ERROR) RCC_DeInit(); // SHUT DOWN, EVERYTHING!
// enable CSS
RCC_ClockSecuritySystemCmd(ENABLE);
// enable PLL
RCC_PLLCmd(ENABLE);
while(!(RCC->CR & RCC_CR_PLLRDY)); // wait for ready
// enable PLL I2S
RCC_PLLI2SCmd(ENABLE);
// set system clock source to PLL
RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);
if(!checkClocks()){
// No actual error reporting done here because we don't want to depend on GPIO etc
while(1);
}
}
void audioInit()
{
I2S_InitTypeDef I2S_InitStructure;
Audio_GPIO_Init();
/*CONFIG the I2S_RCC ,MUST before enabling the I2S APB clock*/
//PLLI2SN 302,PLLI2SR 2,I2SDIV 53,I2SODD 1,FS 44.1KHZ,16bit,Error 0.0011%
RCC_PLLI2SConfig(302,2);
RCC_PLLI2SCmd(ENABLE);
RCC_I2SCLKConfig(RCC_I2S2CLKSource_PLLI2S);
/* Enable the CODEC_I2S peripheral clock */
RCC_APB1PeriphClockCmd(CODEC_I2S_CLK, ENABLE);
/* CODEC_I2S peripheral configuration */
SPI_I2S_DeInit(CODEC_I2S);
I2S_InitStructure.I2S_AudioFreq = AudioFreq;
I2S_InitStructure.I2S_Standard = I2S_Standard_Phillips;
I2S_InitStructure.I2S_DataFormat = I2S_DataFormat_16b;
I2S_InitStructure.I2S_CPOL = I2S_CPOL_Low;//clk 0 when idle state
I2S_InitStructure.I2S_Mode = I2S_Mode_MasterTx;
#ifdef CODEC_MCLK_ENABLED
I2S_InitStructure.I2S_MCLKOutput = I2S_MCLKOutput_Enable;
#elif defined(CODEC_MCLK_DISABLED)
I2S_InitStructure.I2S_MCLKOutput = I2S_MCLKOutput_Disable;
#else
#error "No selection for the MCLK output has been defined !"
#endif /* CODEC_MCLK_ENABLED */
/* Initialize the I2S peripheral with the structure above */
I2S_Init(CODEC_I2S, &I2S_InitStructure);
I2S_Cmd(CODEC_I2S, ENABLE);
//interrupt
#ifdef CODEC_USE_INT
SPI_I2S_ITConfig(CODEC_I2S,SPI_I2S_IT_TXE,ENABLE);
#elif defined(CODEC_USE_DMA)
#error "DMA is not initialized"
#endif
}
