LPCXpresso IDE〜UART通信

/*
 * uart_small.h
 *
 *  Created on: 2013/09/16
 *  Update    : 2014/06/06
 *
 *      Author: easylabo
 */

#ifndef UART_SMALL_H_
#define UART_SMALL_H_

#if CONFIG_ENABLE_DRIVER_UART_SMALL == 1

#define LSR_THRE   0x20
#define LSR_RDR    0x01
#define UART_ECHO  0

extern void UartInit(uint32_t baudrate);
extern void UartPutC(const char c);
extern int UartPutS(const char *s) ;
extern int UartGetC(void);
extern char *UartGetS(char * const buf, const int size);

#endif
#endif /* UART_SMALL_H_ */

/*
 * uart_small.c
 *
 *  Created on: 2013/09/16
 *  Update    : 2014/07/05
 *
 *      Author: easylabo
 */

#include "driver_config.h"

#if CONFIG_ENABLE_DRIVER_UART_SMALL == 1
#include "uart_small.h"

// initialization
void UartInit(uint32_t baudrate) {

    uint32_t                    Fdiv;   // clock divisor ratio

    // P01_7, select function TXD
    LPC_IOCON->PIO1_7 &= ~0x07;         // reset FUNC=0x0
    LPC_IOCON->PIO1_7 |= 0x01;          // set   FUNC=0x1 (TXD)

    // P01_6, select function RXD
    LPC_IOCON->PIO1_6 &= ~0x07;         // reset FUNC=0x0
    LPC_IOCON->PIO1_6 |= 0x01;          // set FUNC=0x1 (RXD)

    // enable UART clock
    LPC_SYSCON->SYSAHBCLKCTRL |= (1<<12);   // UART=1
    LPC_SYSCON->UARTCLKDIV = 0x01;          // divided by 1

    // calculate Fdiv
    Fdiv = (
            SystemCoreClock             // system clock frequency
          * LPC_SYSCON->SYSAHBCLKDIV    // AHB clock divider
        ) / (
            LPC_SYSCON->UARTCLKDIV      // UART clock divider
          * 16 * baudrate               // baud rate
        );

    // set the baud rate divisor value
    LPC_UART->LCR |= 0x80;        // DLAB in LCR must be one in order to access the UART divisor latches
    LPC_UART->DLM = Fdiv / 256;   // set DLM, divisor latches
    LPC_UART->DLL = Fdiv % 256;   // set DLL, divisor latches
    LPC_UART->LCR &= ~0x80;       // disable access to divisor latches (DLAB = 0)

    // UART setting
    LPC_UART->LCR = 0x03;   // 8 bit, 1 stop bit, no parity
    LPC_UART->FCR = 0x07;   // enable an reset TX and RX FIFO
}

// send a character
void UartPutC(const char cPut) {
    while (!(LPC_UART->LSR & LSR_THRE));   // wait for TX buffer ready
    LPC_UART->THR = cPut;
}

// send a string
int UartPutS(const char *sPut) {
    int n;
    for (n = 0; *sPut; sPut++, n++) {
        UartPutC(*sPut);
    }
    return n;
}

// receive a character
int UartGetC(void) {
    while (!(LPC_UART->LSR & LSR_RDR));   // wait for RX buffer valid
    return LPC_UART->RBR;
}

// receive a string, delimiter is CR
char *UartGetS(char * const bufStr, const int sizeOfBuf) {
    // bufStr: line buffer
    // sizeOfBuf: size of bufStr
    int chr;
    int n = 0;

    while (n < sizeOfBuf - 1) {
        chr = UartGetC();
        // detected delimiter CR
        if (chr == '\r') {
            //echo ON or Off
            if(UART_ECHO){
               UartPutS("\r\n");
            }
            break;
        }
        //echo ON or Off
        if(UART_ECHO){
           UartPutC(chr);
        }

        bufStr[n++] = chr;
    }
    bufStr[n] = 0;
    return bufStr;
}

#endif