MSPML1306小练--外部连接TX和RX串口数据FIFO发送和接收

开发板：LP-MSPM0L1306 LaunchPad
例程说明：通过短接TX和RX的引脚，让TX的数据直接发送到RX引脚上，来实现串口发送和接收的例程。使用FIFO的方式实现串口的发送和接收。如果发送和接收都完成，用户LED会闪烁，如果发送和接收没完成，用户LED常亮。
开发板的操作：需要断开J101上TXD和RXD与XDS110-ET下载板的连接，短接TXD与RXD。
例程分析：
1、首先是串口的配置，波特率照常配置，只需要使能FIFO，以及配置发送和接收FIFO的长度即可

2、代码如下所示：

复制

#include "ti_msp_dl_config.h"



/*

 * Configure the internal loopback mode.

 * Note that data received on the UART RXD IO pin will be ignored when

 * loopback is enabled.

 */

#define ENABLE_LOOPBACK_MODE true



/*

 * Number of bytes for UART packet size

 * The packet will be transmitted by the UART.

 * This example uses FIFOs with polling, and the maximum FIFO size is 4.

 * Refer to interrupt examples to handle larger packets.

 */

#define UART_PACKET_SIZE (4)



/* Delay for 5ms to ensure UART TX is idle before starting transmission */

#define UART_TX_DELAY (160000)



/* Data for UART to transmit */

uint8_t txPacket[UART_PACKET_SIZE] = {'M', 'S', 'P', '!'};



/* Data received from UART */

uint8_t rxPacket[UART_PACKET_SIZE];





int main(void)

{

    SYSCFG_DL_init();//系统初始化



    /* Optional delay to ensure UART TX is idle before starting transmission */

    delay_cycles(UART_TX_DELAY);



    /* Set LED to indicate start of transfer */

    DL_GPIO_clearPins(GPIO_LEDS_PORT, GPIO_LEDS_USER_LED_1_PIN);



    /* Fills TX FIFO with data and transmits the data */

    DL_UART_Main_fillTXFIFO(UART_0_INST, &txPacket[0], UART_PACKET_SIZE);//填充数据发送数组并发送数据



    /* Wait until all bytes have been transmitted and the TX FIFO is empty */

    while (DL_UART_Main_isBusy(UART_0_INST))//等待数据发送完毕

        ;



    /*

     * Wait to receive the UART data

     * This loop expects UART_PACKET_SIZE bytes

     */

    for (uint8_t i = 0; i < UART_PACKET_SIZE; i++) {

        rxPacket[i] = DL_UART_receiveDataBlocking(UART_0_INST);

    }//循环接收发送的数据到接收缓存区，因为TX和RX对接了



    /* If write and read were successful, toggle LED */

    //假如发送和接收成功的话，才会进去下面的while循环

    while (1) {

        DL_GPIO_togglePins(GPIO_LEDS_PORT,

            GPIO_LEDS_USER_LED_1_PIN | GPIO_LEDS_USER_TEST_PIN);

        delay_cycles(5000000);

    }

}