lpc177x_8x_uart.c

优龙LPC1788开发板资料

/***********************************************************************//**
 * @file		lpc177x_8x_uart.c
 * @brief		Contains all functions support for UART firmware library
 * 				on LPC177x_8x
 * @version		1.0
 * @date		18. September. 2010
 * @author		NXP MCU SW Application Team
 **************************************************************************
 * Software that is described herein is for illustrative purposes only
 * which provides customers with programming information regarding the
 * products. This software is supplied "AS IS" without any warranties.
 * NXP Semiconductors assumes no responsibility or liability for the
 * use of the software, conveys no license or title under any patent,
 * copyright, or mask work right to the product. NXP Semiconductors
 * reserves the right to make changes in the software without
 * notification. NXP Semiconductors also make no representation or
 * warranty that such application will be suitable for the specified
 * use without further testing or modification.
 **********************************************************************/

/* Peripheral group ----------------------------------------------------------- */
/** @addtogroup UART
 * @{
 */

/* Includes ------------------------------------------------------------------- */
#include "lpc177x_8x_uart.h"
#include "lpc177x_8x_clkpwr.h"

/* Private Functions ---------------------------------------------------------- */

static Status uart_set_divisors(LPC_UART_TypeDef *UARTx, uint32_t baudrate);


/*********************************************************************//**
 * @brief		Determines best dividers to get a target clock rate
 * @param[in]	UARTx	Pointer to selected UART peripheral, should be:
 * 				- LPC_UART0: UART0 peripheral
 * 				- LPC_UART1: UART1 peripheral
 * 				- LPC_UART2: UART2 peripheral
 * 				- LPC_UART3: UART3 peripheral
 * @param[in]	baudrate Desired UART baud rate.
 * @return 		Error status, could be:
 * 				- SUCCESS
 * 				- ERROR
 **********************************************************************/
static Status uart_set_divisors(LPC_UART_TypeDef *UARTx, uint32_t baudrate)
{
	Status errorStatus = ERROR;

	uint32_t uClk;
	uint32_t calcBaudrate = 0;
	uint32_t temp = 0;

	uint32_t mulFracDiv, dividerAddFracDiv;
	uint32_t diviser = 0 ;
	uint32_t mulFracDivOptimal = 1;
	uint32_t dividerAddOptimal = 0;
	uint32_t diviserOptimal = 0;

	uint32_t relativeError = 0;
	uint32_t relativeOptimalError = 100000;

	/* get UART block clock */
	uClk = CLKPWR_GetCLK(CLKPWR_CLKTYPE_PER);

	uClk = uClk >> 4; /* div by 16 */

	/* In the Uart IP block, baud rate is calculated using FDR and DLL-DLM registers
	* The formula is :
	* BaudRate= uClk * (mulFracDiv/(mulFracDiv+dividerAddFracDiv) / (16 * (DLL)
	* It involves floating point calculations. That's the reason the formulae are adjusted with
	* Multiply and divide method.*/
	/* The value of mulFracDiv and dividerAddFracDiv should comply to the following expressions:
	* 0 < mulFracDiv <= 15, 0 <= dividerAddFracDiv <= 15 */
	for (mulFracDiv = 1 ; mulFracDiv <= 15 ;mulFracDiv++)
	{
		for (dividerAddFracDiv = 0 ; dividerAddFracDiv <= 15 ;dividerAddFracDiv++)
		{
			temp = (mulFracDiv * uClk) / ((mulFracDiv + dividerAddFracDiv));

			diviser = temp / baudrate;

			if ((temp % baudrate) > (baudrate / 2))
				diviser++;

			if (diviser > 2 && diviser < 65536)
			{
				calcBaudrate = temp / diviser;

				if (calcBaudrate <= baudrate)
					relativeError = baudrate - calcBaudrate;
				else
					relativeError = calcBaudrate - baudrate;

				if ((relativeError < relativeOptimalError))
				{
					mulFracDivOptimal = mulFracDiv ;

					dividerAddOptimal = dividerAddFracDiv;

					diviserOptimal = diviser;

					relativeOptimalError = relativeError;

					if (relativeError == 0)
						break;
				}
			} /* End of if */
		} /* end of inner for loop */

		if (relativeError == 0)
			break;
	} /* end of outer for loop  */

	if (relativeOptimalError < ((baudrate * UART_ACCEPTED_BAUDRATE_ERROR)/100))
	{
		if (((LPC_UART1_TypeDef *)UARTx) == LPC_UART1)
		{
			((LPC_UART1_TypeDef *)UARTx)->LCR |= UART_LCR_DLAB_EN;

			((LPC_UART1_TypeDef *)UARTx)->DLM = UART_LOAD_DLM(diviserOptimal);

			((LPC_UART1_TypeDef *)UARTx)->DLL = UART_LOAD_DLL(diviserOptimal);

			/* Then reset DLAB bit */
			((LPC_UART1_TypeDef *)UARTx)->LCR &= (~UART_LCR_DLAB_EN) & UART_LCR_BITMASK;

			((LPC_UART1_TypeDef *)UARTx)->FDR = (UART_FDR_MULVAL(mulFracDivOptimal) \
													| UART_FDR_DIVADDVAL(dividerAddOptimal)) & UART_FDR_BITMASK;
		}
		else
		{
			UARTx->LCR |= UART_LCR_DLAB_EN;

			UARTx->DLM = UART_LOAD_DLM(diviserOptimal);

			UARTx->DLL = UART_LOAD_DLL(diviserOptimal);

			/* Then reset DLAB bit */
			UARTx->LCR &= (~UART_LCR_DLAB_EN) & UART_LCR_BITMASK;

			UARTx->FDR = (UART_FDR_MULVAL(mulFracDivOptimal) \
							| UART_FDR_DIVADDVAL(dividerAddOptimal)) & UART_FDR_BITMASK;
		}

		errorStatus = SUCCESS;
	}

	return errorStatus;
}

/* End of Private Functions ---------------------------------------------------- */


/* Public Functions ----------------------------------------------------------- */
/** @addtogroup UART_Public_Functions
 * @{
 */
/* UART Init/DeInit functions -------------------------------------------------*/
/********************************************************************//**
 * @brief		Initializes the UARTx peripheral according to the specified
 *               parameters in the UART_ConfigStruct.
 * @param[in]	UARTx	UART peripheral selected, should be:
 *   			- LPC_UART0: UART0 peripheral
 * 				- LPC_UART1: UART1 peripheral
 * 				- LPC_UART2: UART2 peripheral
 * 				- LPC_UART3: UART3 peripheral
 *				- LPC_UART4: UART4 peripheral
 * @param[in]	UART_ConfigStruct Pointer to a UART_CFG_Type structure
*                    that contains the configuration information for the
*                    specified UART peripheral.
 * @return 		None
 *********************************************************************/
void UART_Init(LPC_UART_TypeDef *UARTx, UART_CFG_Type *UART_ConfigStruct)
{
	uint32_t tmp;

	if(UARTx == LPC_UART0)
	{
		/* Set up clock and power for UART module */
		CLKPWR_ConfigPPWR (CLKPWR_PCONP_PCUART0, ENABLE);
	}
	if(((LPC_UART1_TypeDef *)UARTx) == LPC_UART1)
	{
		/* Set up clock and power for UART module */
		CLKPWR_ConfigPPWR (CLKPWR_PCONP_PCUART1, ENABLE);
	}
	if(UARTx == LPC_UART2)
	{
		/* Set up clock and power for UART module */
		CLKPWR_ConfigPPWR (CLKPWR_PCONP_PCUART2, ENABLE);
	}
	if(UARTx == LPC_UART3)
	{
		/* Set up clock and power for UART module */
		CLKPWR_ConfigPPWR (CLKPWR_PCONP_PCUART3, ENABLE);
	}

	/* FIFOs are empty */
	UARTx->FCR = ( UART_FCR_FIFO_EN | UART_FCR_RX_RS | UART_FCR_TX_RS);

	// Disable FIFO
	UARTx->FCR = 0;

	// Dummy reading
	while (UARTx->LSR & UART_LSR_RDR)
	{
		tmp = UARTx->RBR;
	}

	UARTx->TER = UART_TER_TXEN;

	// Wait for current transmit complete
	while (!(UARTx->LSR & UART_LSR_THRE));

	// Disable Tx
	UARTx->TER = 0;

	// Disable interrupt
	UARTx->IER = 0;

	// Set LCR to default state
	UARTx->LCR = 0;

	// Set ACR to default state
	UARTx->ACR = 0;

	// Set RS485 control to default state
	UARTx->RS485CTRL = 0;

	// Set RS485 delay timer to default state
	UARTx->RS485DLY = 0;

	// Set RS485 addr match to default state
	UARTx->ADRMATCH = 0;

	// Dummy reading
	tmp = UARTx->LSR;

	if(((LPC_UART1_TypeDef *)UARTx) == LPC_UART1)
	{
		// Set Modem Control to default state
		((LPC_UART1_TypeDef *)UARTx)->MCR = 0;

		//Dummy Reading to Clear Status
		tmp = ((LPC_UART1_TypeDef *)UARTx)->MSR;
	}
	else
	{
		// Set IrDA to default state for all UART other than UART1
		UARTx->ICR = 0;
	}

	// Set Line Control register ----------------------------

	uart_set_divisors(UARTx, (UART_ConfigStruct->Baud_rate));

	if (((LPC_UART1_TypeDef *)UARTx) == LPC_UART1)
	{
		tmp = (((LPC_UART1_TypeDef *)UARTx)->LCR & (UART_LCR_DLAB_EN | UART_LCR_BREAK_EN)) \
													& UART_LCR_BITMASK;
	}
	else
	{
		tmp = (UARTx->LCR & (UART_LCR_DLAB_EN | UART_LCR_BREAK_EN)) & UART_LCR_BITMASK;
	}

	switch (UART_ConfigStruct->Databits)
	{
		case UART_DATABIT_5:
			tmp |= UART_LCR_WLEN5;
			break;

		case UART_DATABIT_6:
			tmp |= UART_LCR_WLEN6;
			break;

		case UART_DATABIT_7:
			tmp |= UART_LCR_WLEN7;
			break;

		case UART_DATABIT_8:

		default:
			tmp |= UART_LCR_WLEN8;
			break;
	}

	if (UART_ConfigStruct->Parity == UART_PARITY_NONE)
	{
		// Do nothing...
	}
	else
	{
		tmp |= UART_LCR_PARITY_EN;
		switch (UART_ConfigStruct->Parity)
		{
			case UART_PARITY_ODD:
				tmp |= UART_LCR_PARITY_ODD;
				break;

			case UART_PARITY_EVEN:
				tmp |= UART_LCR_PARITY_EVEN;
				break;

			case UART_PARITY_SP_1:
				tmp |= UART_LCR_PARITY_F_1;
				break;

			case UART_PARITY_SP_0:
				tmp |= UART_LCR_PARITY_F_0;
				break;

			default:
				break;
		}
	}

	switch (UART_ConfigStruct->Stopbits)
	{
		case UART_STOPBIT_2:
			tmp |= UART_LCR_STOPBIT_SEL;
			break;

		case UART_STOPBIT_1:

		default:
			// Do no thing
			break;
	}


	// Write back to LCR, configure FIFO and Disable Tx
	if (((LPC_UART1_TypeDef *)UARTx) ==  LPC_UART1)
	{
		((LPC_UART1_TypeDef *)UARTx)->LCR = (uint8_t)(tmp & UART_LCR_BITMASK);
	}
	else
	{
		UARTx->LCR = (uint8_t)(tmp & UART_LCR_BITMASK);
	}
}

/*********************************************************************//**
 * @brief		De-initializes the UARTx peripheral registers to their
 *                  default reset values.
 * @param[in]	UARTx	UART peripheral selected, should be:
 *   			- LPC_UART0: UART0 peripheral
 * 				- LPC_UART1: UART1 peripheral
 * 				- LPC_UART2: UART2 peripheral
 * 				- LPC_UART3: UART3 peripheral
 * @return 		None
 **********************************************************************/
void UART_DeInit(LPC_UART_TypeDef* UARTx)
{
	UART_TxCmd(UARTx, DISABLE);

	if (UARTx == LPC_UART0)
	{
		/* Set up clock and power for UART module */
		CLKPWR_ConfigPPWR (CLKPWR_PCONP_PCUART0, DISABLE);
	}

	if (((LPC_UART1_TypeDef *)UARTx) == LPC_UART1)
	{
		/* Set up clock and power for UART module */
		CLKPWR_ConfigPPWR (CLKPWR_PCONP_PCUART1, DISABLE);
	}

	if (UARTx == LPC_UART2)
	{
		/* Set up clock and power for UART module */
		CLKPWR_ConfigPPWR (CLKPWR_PCONP_PCUART2, DISABLE);
	}

	if (UARTx == LPC_UART3)
	{
		/* Set up clock and power for UART module */
		CLKPWR_ConfigPPWR (CLKPWR_PCONP_PCUART3, DISABLE);
	}
}

/*****************************************************************************//**
* @brief		Fills each UART_InitStruct member with its default value:
* 				- 9600 bps
* 				- 8-bit data
* 				- 1 Stopbit
* 				- None Parity
* @param[in]	UART_InitStruct Pointer to a UART_CFG_Type structure
*                    which will be initialized.
* @return		None
*******************************************************************************/
void UART_ConfigStructInit(UART_CFG_Type *UART_InitStruct)
{
	UART_InitStruct->Baud_rate = 115200;

	UART_InitStruct->Databits = UART_DATABIT_8;

	UART_InitStruct->Parity = UART_PARITY_NONE;

	UART_InitStruct->Stopbits = UART_STOPBIT_1;
}

/* UART Send/Recieve functions -------------------------------------------------*/
/*********************************************************************//**
 * @brief		Transmit a single data through UART peripheral
 * @param[in]	UARTx	UART peripheral selected, should be:
 *   			- LPC_UART0: UART0 peripheral
 * 				- LPC_UART1: UART1 peripheral
 * 				- LPC_UART2: UART2 peripheral
 * 				- LPC_UART3: UART3 peripheral
 * @param[in]	Data	Data to transmit (must be 8-bit long)
 * @return 		None
 **********************************************************************/
void UART_SendByte(LPC_UART_TypeDef* UARTx, uint8_t Data)
{
	if (((LPC_UART1_TypeDef *)UARTx) == LPC_UART1)
	{
		((LPC_UART1_TypeDef *)UARTx)->THR = Data & UART_THR_MASKBIT;
	}
	else
	{
		UARTx->THR = Data & UART_THR_MASKBIT;
	}

}


/*********************************************************************//**
 * @brief		Receive a single data from UART peripheral
 * @param[in]	UARTx	UART peripheral selected, should be:
 *  			- LPC_UART0: UART0 peripheral
 * 				- LPC_UART1: UART1 peripheral
 * 				- LPC_UART2: UART2 peripheral
 * 				- LPC_UART3: UART3 peripheral
 * @return 		Data received
 **********************************************************************/
uint8_t UART_ReceiveByte(LPC_UART_TypeDef* UARTx)
{
	if (((LPC_UART1_TypeDef *)UARTx) == LPC_UART1)
	{
		return (((LPC_UART1_TypeDef *)UARTx)->RBR & UART_RBR_MASKBIT);
	}
	else
	{
		return (UARTx->RBR & UART_RBR_MASKBIT);
	}