lpc177x_8x_i2s.c

来自「NXPl788上lwip的无操作系统移植,基于Embest开发板」· C语言 代码 · 共 590 行 · 第 1/2 页

	cclk = CLKPWR_GetCLK(CLKPWR_CLKTYPE_CPU);

	if(TRMode == I2S_TX_MODE)
	{
		channel = i2s_GetChannel(I2Sx,I2S_TX_MODE);
		wordwidth = i2s_GetWordWidth(I2Sx,I2S_TX_MODE);
	}
	else
	{
		channel = i2s_GetChannel(I2Sx,I2S_RX_MODE);
		wordwidth = i2s_GetWordWidth(I2Sx,I2S_RX_MODE);
	}

	/* Calculate X and Y divider
	 * The MCLK rate for the I2S transmitter is determined by the value
	 * in the I2STXRATE/I2SRXRATE register. The required I2STXRATE/I2SRXRATE
	 * setting depends on the desired audio sample rate desired, the format
	 * (stereo/mono) used, and the data size.
	 * The formula is:
	 * 		I2S_MCLK = CCLK * (X/Y) / 2
	 * We have:
	 * 		I2S_MCLK = Freq * channel*wordwidth * (I2Sx->TXBITRATE+1);
	 * So: (X/Y) = (Freq * channel*wordwidth * (I2Sx->TXBITRATE+1))/CCLK*2
	 * We use a loop function to chose the most suitable X,Y value
	 */

	/* divider is a fixed point number with 16 fractional bits */
	divider = (((uint64_t)Freq *channel*wordwidth * 2)<<16) / cclk;

	/* find N that make x/y <= 1 -> divider <= 2^16 */
	for(N=64;N>0;N--){
		if((divider*N) < (1<<16)) break;
	}

	if(N == 0) return ERROR;

	divider *= N;

	for (y = 255; y > 0; y--) {
		x = y * divider;
		if(x & (0xFF000000)) continue;
		dif = x & 0xFFFF;
		if(dif>0x8000) err = 0x10000-dif;
		else err = dif;
		if (err == 0)
		{
			y_divide = y;
			break;
		}
		else if (err < ErrorOptimal)
		{
			ErrorOptimal = err;
			y_divide = y;
		}
	}
	x_divide = ((uint64_t)y_divide * Freq *(channel*wordwidth)* N * 2)/cclk;
	if(x_divide >= 256) x_divide = 0xFF;
	if(x_divide == 0) x_divide = 1;
	
	if (TRMode == I2S_TX_MODE)// Transmitter
	{
		I2Sx->TXBITRATE = N-1;
		I2Sx->TXRATE = y_divide | (x_divide << 8);
	} else //Receiver
	{
		I2Sx->RXBITRATE = N-1;
		I2Sx->TXRATE = y_divide | (x_divide << 8);
	}
	return SUCCESS;
}

/********************************************************************//**
 * @brief		I2S set bitrate
 * @param[in]	I2Sx I2S peripheral selected, should be: LPC_I2S
 * @param[in]	bitrate value will be set
 * 				bitrate value should be in range: 0 .. 63
 * @param[in]	TRMode is transmit/receive mode, should be:
 * 				- I2S_TX_MODE = 0: transmit mode
 * 				- I2S_RX_MODE = 1: receive mode
 * @return 		none
 *********************************************************************/
void I2S_SetBitRate(LPC_I2S_TypeDef *I2Sx, uint8_t bitrate, uint8_t TRMode)
{
	if(TRMode == I2S_TX_MODE)
	{
		I2Sx->TXBITRATE = bitrate;
	}
	else
	{
		I2Sx->RXBITRATE = bitrate;
	}
}

/********************************************************************//**
 * @brief		Configuration operating mode for I2S
 * @param[in]	I2Sx I2S peripheral selected, should be: LPC_I2S
 * @param[in]	ModeConfig pointer to I2S_MODEConf_Type will be used to
 * 				configure
 * @param[in]	TRMode is transmit/receive mode, should be:
 * 				- I2S_TX_MODE = 0: transmit mode
 * 				- I2S_RX_MODE = 1: receive mode
 * @return 		none
 *********************************************************************/
void I2S_ModeConfig(LPC_I2S_TypeDef *I2Sx, I2S_MODEConf_Type* ModeConfig,
		uint8_t TRMode)
{
	if (TRMode == I2S_TX_MODE) {
		I2Sx->TXMODE &= ~0x0F; //clear bit 3:0 in I2STXMODE register
		if (ModeConfig->clksel == I2S_CLKSEL_MCLK) {
			I2Sx->TXMODE |= 0x02;
		}
		if (ModeConfig->fpin == I2S_4PIN_ENABLE) {
			I2Sx->TXMODE |= (1 << 2);
		}
		if (ModeConfig->mcena == I2S_MCLK_ENABLE) {
			I2Sx->TXMODE |= (1 << 3);
		}
	} else {
		I2Sx->RXMODE &= ~0x0F; //clear bit 3:0 in I2STXMODE register
		if (ModeConfig->clksel == I2S_CLKSEL_MCLK) {
			I2Sx->RXMODE |= 0x02;
		}
		if (ModeConfig->fpin == I2S_4PIN_ENABLE) {
			I2Sx->RXMODE |= (1 << 2);
		}
		if (ModeConfig->mcena == I2S_MCLK_ENABLE) {
			I2Sx->RXMODE |= (1 << 3);
		}
	}
}

/********************************************************************//**
 * @brief		Configure DMA operation for I2S
 * @param[in]	I2Sx I2S peripheral selected, should be: LPC_I2S
 * @param[in]	DMAConfig pointer to I2S_DMAConf_Type will be used to configure
 * @param[in]	TRMode is transmit/receive mode, should be:
 * 				- I2S_TX_MODE = 0: transmit mode
 * 				- I2S_RX_MODE = 1: receive mode
 * @return 		none
 *********************************************************************/
void I2S_DMAConfig(LPC_I2S_TypeDef *I2Sx, I2S_DMAConf_Type* DMAConfig,
		uint8_t TRMode)
{
	if (TRMode == I2S_RX_MODE) {
		if (DMAConfig->DMAIndex == I2S_DMA_1) {
			LPC_I2S->DMA1 = (DMAConfig->depth) << 8;
		} else {
			LPC_I2S->DMA2 = (DMAConfig->depth) << 8;
		}
	} else {
		if (DMAConfig->DMAIndex == I2S_DMA_1) {
			LPC_I2S->DMA1 = (DMAConfig->depth) << 16;
		} else {
			LPC_I2S->DMA2 = (DMAConfig->depth) << 16;
		}
	}
}

/********************************************************************//**
 * @brief		Enable/Disable DMA operation for I2S
 * @param[in]	I2Sx: I2S peripheral selected, should be: LPC_I2S
 * @param[in]	DMAIndex chose what DMA is used, should be:
 * 				- I2S_DMA_1 = 0: DMA1
 * 				- I2S_DMA_2 = 1: DMA2
 * @param[in]	TRMode is transmit/receive mode, should be:
 * 				- I2S_TX_MODE = 0: transmit mode
 * 				- I2S_RX_MODE = 1: receive mode
 * @param[in]	NewState is new state of DMA operation, should be:
 * 				- ENABLE
 * 				- DISABLE
 * @return 		none
 *********************************************************************/
void I2S_DMACmd(LPC_I2S_TypeDef *I2Sx, uint8_t DMAIndex, uint8_t TRMode,
		FunctionalState NewState)
{
	if (TRMode == I2S_RX_MODE) {
		if (DMAIndex == I2S_DMA_1) {
			if (NewState == ENABLE)
				I2Sx->DMA1 |= 0x01;
			else
				I2Sx->DMA1 &= ~0x01;
		} else {
			if (NewState == ENABLE)
				I2Sx->DMA2 |= 0x01;
			else
				I2Sx->DMA2 &= ~0x01;
		}
	} else {
		if (DMAIndex == I2S_DMA_1) {
			if (NewState == ENABLE)
				I2Sx->DMA1 |= 0x02;
			else
				I2Sx->DMA1 &= ~0x02;
		} else {
			if (NewState == ENABLE)
				I2Sx->DMA2 |= 0x02;
			else
				I2Sx->DMA2 &= ~0x02;
		}
	}
}

/********************************************************************//**
 * @brief		Configure IRQ for I2S
 * @param[in]	I2Sx I2S peripheral selected, should be: LPC_I2S
 * @param[in]	TRMode is transmit/receive mode, should be:
 * 				- I2S_TX_MODE = 0: transmit mode
 * 				- I2S_RX_MODE = 1: receive mode
 * @param[in]	level is the FIFO level that triggers IRQ request
 * @return 		none
 *********************************************************************/
void I2S_IRQConfig(LPC_I2S_TypeDef *I2Sx, uint8_t TRMode, uint8_t level) {
	if (TRMode == I2S_RX_MODE) {
		I2Sx->IRQ |= (level << 8);
	} else {
		I2Sx->IRQ |= (level << 16);
	}
}

/********************************************************************//**
 * @brief		Enable/Disable IRQ for I2S
 * @param[in]	I2Sx I2S peripheral selected, should be: LPC_I2S
 * @param[in]	TRMode is transmit/receive mode, should be:
 * 				- I2S_TX_MODE = 0: transmit mode
 * 				- I2S_RX_MODE = 1: receive mode
 * @param[in]	NewState is new state of DMA operation, should be:
 * 				- ENABLE
 * 				- DISABLE
 * @return 		none
 *********************************************************************/
void I2S_IRQCmd(LPC_I2S_TypeDef *I2Sx, uint8_t TRMode, FunctionalState NewState) {

	if (TRMode == I2S_RX_MODE) {
		if (NewState == ENABLE)
			I2Sx->IRQ |= 0x01;
		else
			I2Sx->IRQ &= ~0x01;
		//Enable DMA

	} else {
		if (NewState == ENABLE)
			I2Sx->IRQ |= 0x02;
		else
			I2Sx->IRQ &= ~0x02;
	}
}

/********************************************************************//**
 * @brief		Get I2S interrupt status
 * @param[in]	I2Sx I2S peripheral selected, should be: LPC_I2S
 * @param[in]	TRMode is transmit/receive mode, should be:
 * 				- I2S_TX_MODE = 0: transmit mode
 * 				- I2S_RX_MODE = 1: receive mode
 * @return 		FunctionState	should be:
 * 				- ENABLE: interrupt is enable
 * 				- DISABLE: interrupt is disable
 *********************************************************************/
FunctionalState I2S_GetIRQStatus(LPC_I2S_TypeDef *I2Sx,uint8_t TRMode)
{

	if(TRMode == I2S_TX_MODE)
		return I2S_IS_ENABLED((I2Sx->IRQ >> 1)&0x01);
	else
		return I2S_IS_ENABLED((I2Sx->IRQ)&0x01);
}

/********************************************************************//**
 * @brief		Get I2S interrupt depth
 * @param[in]	I2Sx I2S peripheral selected, should be: LPC_I2S
 * @param[in]	TRMode is transmit/receive mode, should be:
 * 				- I2S_TX_MODE = 0: transmit mode
 * 				- I2S_RX_MODE = 1: receive mode
 * @return 		depth of FIFO level on which to create an irq request
 *********************************************************************/
uint8_t I2S_GetIRQDepth(LPC_I2S_TypeDef *I2Sx,uint8_t TRMode)
{

	if(TRMode == I2S_TX_MODE)
		return (((I2Sx->IRQ)>>16)&0xFF);
	else
		return (((I2Sx->IRQ)>>8)&0xFF);
}
/**
 * @}
 */

#endif /*_I2S*/

/**
 * @}
 */

/* --------------------------------- End Of File ------------------------------ */