嵌入式实验四：串口传输实验(共48页)

1、精选优质文档-倾情为你奉上实 验 报 告课程名称 嵌入式系统设计 实验仪器 清华同方辰源嵌入式系统实验箱 实验名称 实验四：串口传输实验 系 别 计算机学院 专 业 计算机科学与技术 班级/学号 学生姓名 实验日期 成 绩 指导教师 实验四：串口传输实验1、 实验问题回答（1） 本实验引入了Send和Receive两个变量表示上传或下传数据，用状态机怎么实现？答：switch(oledkey0)case 'F': state=1;/Receive = 1;/Send = 0;break;case 'E': state=2;/Send = 1;/Receive =

2、 0;break;switch(state)case 0:break;case 1: recive();break;case 2:send();break;（2） 了解串口通讯原理。答：串口按位（bit）发送和接收字节，串口通信最重要的参数是波特率、数据位、停止位和奇偶校验。对于两个进行通信的端口，这些参数必须匹配。1、51系列单片机的串口有4个模式，可分别用作串并转换、并串转换、异步串行通信（2种模式）。异步串行通信中，有1+8+1和1+8+1+1两种帧格式，多机通信是特殊的通信方式。2、基本原理是两组移位寄存器。将并行通信转换成串行通信模式（发送部分），或反之（接收部分）。可全双工运行。3

3、、速度通过移位脉冲决定。具体一般通过定时器1的自动装载模式产生的溢出脉冲给出。4、电平上采用的是CMOS逻辑。5、以上是物理层和数据链路层的单片机串口模块的约定，其他层需要软件人员根据需要自行把握。另外，电平需要根据实际通信环境做变换，如232、485或红外等。（3）了解在上位机（PC端）端，C程序中如何调用串口？ 答：#include <Windows.h>#include <stdio.h>HANDLE hCom;int main(void)hCom=CreateFile(TEXT("COM3"),/COM

4、1口GENERIC_READ|GENERIC_WRITE, /允许读和写0, /独占方式NULL,OPEN_EXISTING, /打开而不是创建0, /同步方式NULL);if(hCom=(HANDLE)-1)printf("打开COM失败!n");return FALSE;elseprintf("COM打开成功！n");SetupComm(hCom,1024,1024); /输入缓冲区和输出缓冲区的大小都是1024COMMTIMEOUTS TimeOuts;/设定读超时TimeOut

5、s.ReadIntervalTimeout=1000;TimeOuts.ReadTotalTimeoutMultiplier=500;TimeOuts.ReadTotalTimeoutConstant=5000;/设定写超时TimeOuts.WriteTotalTimeoutMultiplier=500;TimeOuts.WriteTotalTimeoutConstant=2000;SetCommTimeouts(hCom,&TimeOuts); /设置超时DCB dcb;GetCommState(hCom,&dcb);dcb.BaudRate=9600;&

6、#160;/波特率为9600dcb.ByteSize=8; /每个字节有8位dcb.Parity=NOPARITY; /无奇偶校验位dcb.StopBits=ONE5STOPBITS; /两个停止位SetCommState(hCom,&dcb);DWORD wCount;/读取的字节数BOOL bReadStat;while(1)PurgeComm(hCom,PURGE_TXCLEAR|PURGE_RXCLEAR); /清空缓冲区char str9=0;printf("%sn",str);bRea

7、dStat=ReadFile(hCom,str,9,&wCount,NULL);if(!bReadStat)printf("读串口失败!");return FALSE;elsestr8='0'printf("%sn",str);Sleep(100);（4） 了解在上位机（PC端）端，JAVA程序中如何调用串口？答：public static void process() try Enumeration portList = CommPortIdentifier.getPortIdentifiers(); while (p

8、ortList.hasMoreElements() CommPortIdentifier portId = (CommPortIdentifier) portList.nextElement(); if (portId.getPortType() = CommPortIdentifier.PORT_SERIAL)/如果端口类型是串口则判断名称 if(portId.getName().equals("COM1")/如果是COM1端口则退出循环 break; else portId=null; SerialPort serialPort = (SerialPort)portId

9、.open("Serial_Communication", 1000);/打开串口的超时时间为1000ms serialPort.setSerialPortParams(9600,SerialPort.DATABITS_8,SerialPort.STOPBITS_1,SerialPort.PARITY_NONE);/设置串口速率为9600，数据位8位，停止位1们，奇偶校验无 InputStream in = serialPort.getInputStream();/得到输入流 OutputStream out = serialPort.getOutputStream();/

10、得到输出流 /进行输入输出操作/操作结束后 in.close(); out.close(); serialPort.close();/关闭串口 catch (PortInUseException e) e.printStackTrace(); catch (UnsupportedCommOperationException e) e.printStackTrace(); catch (IOException e) e.printStackTrace(); 2、 实验目的和效果实验目的：（1）学习、理解、掌握利用串口实现上位机和下位机之间的通讯（数据上传和控制）。达到实验要求，拓展二未实现。实验

11、效果：3、 实验内容和步骤实验内容：（1） 默认在在OLED屏幕上分行显示串口号、波特率、数据位、校验位、停止位、“E”键发送模式、“F”键接收模式。思路：E键发送模式设置send=1 receive=0 F键接受模式设置 send=0 receive=1（2） 按下小键盘的“E”键，表示下位机（实验箱）往上位机（PC）发送数据，上位机开启“超级终端”，下位机循环往上位机发送“0”“1”“2”。“9”字符，上位机在“超级终端”中可以看到。思路：定义一个全局变量字符数组，char rxchar2;GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_0,GPIO_PIN_

12、0);SysCtlDelay();UARTSend(unsigned char *)&rxchar, 1);SysCtlDelay();GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_0,0);rxchar0值不断由0x30-0x39之间进行变化。if(rxchar0 >= 0x39) | (rxchar0 < 0x30)rxchar0 = 0x30;elserxchar0+;（3） 按下小键盘的“F”键，表示上位机（PC）往下位机（实验箱）发送数据，上位机开启“超级终端”，输入“A”、“B”、“C”、“D”等，下位机接受数据，和小键盘输入一样

13、进行相应显示。思路：if(UARTCharsAvail(UART0_BASE)rxchar0 = UARTCharGet(UART0_BASE); / 等待接收字符rxchar1 = '0'GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_0,GPIO_PIN_0);RIT128x96x4StringDraw("Receive: ", 12,80, 15); RIT128x96x4StringDraw(rxchar, 66,80,15);RIT128x96x4StringDraw(" ", 72,80,15);

14、 SysCtlDelay();GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_0,0);（4） 扩展：按照状态机模式修改程序。思路：根据按键的不同判断状态，三种状态，空闲，接收，发送。根据状态的不同调用相应的方法。（5） 扩展：在另外一片CPU LM3S 2110上实现串口通信，接实验箱第二个串口接口，因为这一片CPU不带显示器，可以只实现下位机（实验箱）往上位机（PC）发送数据，上位机开启“超级终端”，下位机循环往上位机发送“0”“1”“2”。“9”字符，上位机在“超级终端”中可以看到。思路：理论上在创建项目时选择cpu LM3S 2110，改变实验箱上连线，连

15、接UART2的串口即可实现。但实际操作中并未实现。实验步骤：（1） 加载必要程序（2） 串口启动配置（main）（3） 增加串口相关函数（main.c中）（4） 修改主函数，实现本次实验要求的功能（5） 编译、连接，生成可执行程序文件（6） 反复（3）-（5）步骤，直到完成（7） 硬件连接,连接标志UART1的串口（8） 联调4、 实验总结与收获实验代码#include <stdio.h>#include <LM3Sxxxx.H>#include <hw_ints.h>#include <hw_memmap.h>#include <hw_t

16、ypes.h>#include <gpio.h>#include <interrupt.h>#include <sysctl.h>#include <uart.h>#include "rit128x96x4.h" /#include "utility.h" #define MAX_SIZE 40 / 缓冲区最大限制长度#define UARTCharGetNB UARTCharGetNonBlockingchar RxBuf1 + MAX_SIZE; / 接收缓冲区int BufP = 0; / 缓冲

17、区位置变量tBoolean RxEndFlag = false; / 接收结束标志unsigned int Event=0,Event_key=0,Send=0,Receive=0;int type=0;int ki=0;char oledkey2;int state=0;unsigned char ucValue=0x00;long time=0;int Speed,count=0;unsigned char rxchar10;void timerset(void);void UARTSend(const unsigned char *pucBuffer, unsigned long ulC

18、ount);void recive()if(UARTCharsAvail(UART0_BASE)rxchar0 = UARTCharGet(UART0_BASE); / 等待接收字符rxchar1 = '0'GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_0,GPIO_PIN_0);RIT128x96x4StringDraw("Receive: ", 30,80, 15);RIT128x96x4StringDraw(rxchar, 66,80,15);RIT128x96x4StringDraw(" ", 72

19、,80,15);SysCtlDelay();GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_0,0);void send() RIT128x96x4StringDraw("sending1",0,60,15);GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_0,GPIO_PIN_0);SysCtlDelay();/RIT128x96x4StringDraw("sending2",20,1,15);UARTSend(unsigned char *)&rxchar, 1);SysCtlDel

20、ay();GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_0,0);if(rxchar0 >= 0x39) | (rxchar0 < 0x30)rxchar0 = 0x30;elserxchar0+;RIT128x96x4StringDraw("sended ",1,1,15);int main()/声明部分rxchar0=0x30;rxchar1='0'/初始化/* Set the clocking to run from PLL at 50 MHz */SysCtlClockSet(SYSCTL_SYSDIV_1

21、 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN | SYSCTL_XTAL_8MHZ);RIT128x96x4Init();RIT128x96x4Clear();/设置时钟中断1SysTickPeriodSet(SysCtlClockGet()/100); SysTickEnable();SysTickIntEnable();/*/设置键盘中断/*使能外设GPIO */SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOC);SysCtlPeripher

22、alEnable(SYSCTL_PERIPH_GPIOD);SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);/*设置GPIO 为输入 */GPIOPinTypeGPIOInput(GPIO_PORTD_BASE, GPIO_PIN_7);GPIOPinTypeGPIOInput(GPIO_PORTC_BASE, GPIO_PIN_4);/*配置GPIO 端口为输出/ 7segd1(

23、PB6);7segd2(PB4);7segd3(PB5)GPIOPinTypeGPIOOutput(GPIO_PORTB_BASE, GPIO_PIN_4 | GPIO_PIN_5 | GPIO_PIN_6);/ bitcode0(PC5);bitcode1(PC6);bitcode2(PC7)GPIOPinTypeGPIOOutput(GPIO_PORTC_BASE, GPIO_PIN_5 | GPIO_PIN_6 | GPIO_PIN_7);/ 7segd0(PD4);7segdot(PD5);rst(PD6)GPIOPinTypeGPIOOutput(GPIO_PORTD_BASE, G

24、PIO_PIN_4 | GPIO_PIN_5 | GPIO_PIN_6);*/*使能中断 */IntEnable(INT_GPIOD);IntMasterEnable();GPIOPinIntEnable(GPIO_PORTD_BASE, GPIO_PIN_7);GPIOIntTypeSet(GPIO_PORTD_BASE, GPIO_PIN_7, GPIO_RISING_EDGE);/*GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_0);GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PI

25、N_1);/ Configure the UART for 115,200, 8N1 operation.UARTConfigSetExpClk(UART0_BASE, SysCtlClockGet(), ,(UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE |UART_CONFIG_PAR_NONE);UARTFIFOLevelSet(UART0_BASE, / 设置发送和接收FIFO 深度UART_FIFO_TX4_8,UART_FIFO_RX6_8);IntEnable(INT_UART0);UARTIntEnable(UART0_BASE, UART_

26、INT_RX | UART_INT_RT);timerset();/计时器初始化timerset();/计时器初始化 RIT128x96x4StringDraw("com1", 0, 0, 15);/显示串口号RIT128x96x4StringDraw("", 0, 20, 15);/显示波特率/*unsigned char a= *pulConfig;char d30;char b30;d=*a+1;b=*a+2;*/RIT128x96x4StringDraw("8", 0, 40, 15);/显示数据位/unsigned long

27、 parity=UARTParityModeGet(UART0_BASE);/sprintf(p,"%d",parity );RIT128x96x4StringDraw("wu", 0, 60, 15);/显示校验位RIT128x96x4StringDraw("1", 0, 80, 15);/显示停止位RIT128x96x4StringDraw("E:send",1,31,15);RIT128x96x4StringDraw("F:receiave",1,41,15);while(1) if(Ev

28、ent)Event = 0; if(Event_key)Event_key = 0;switch(oledkey0)/*case '0':Draw_Char_H(0);break;case '1':Reset_Counter_Speed(128);Speed = 128;break;*/case 'F': state=1;/Receive = 1;/Send = 0;break;case 'E': state=2;/Send = 1;/Receive = 0;break;default:state=0;break; switch(

29、state)case 0:break;case 1: recive();break;case 2:send();break;default:/state=0;break; /*if(Send)RIT128x96x4StringDraw("sending1",0,60,15);GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_0,GPIO_PIN_0);SysCtlDelay();/RIT128x96x4StringDraw("sending2",20,1,15);UARTSend(unsigned char *)&rx

30、char, 1);SysCtlDelay();GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_0,0);if(rxchar0 >= 0x39) | (rxchar0 < 0x30)rxchar0 = 0x30;elserxchar0+;RIT128x96x4StringDraw("sended ",1,1,15);if(Receive) if(UARTCharsAvail(UART0_BASE)rxchar0 = UARTCharGet(UART0_BASE); / 等待接收字符rxchar1 = '0'GPIOPi

31、nWrite(GPIO_PORTF_BASE, GPIO_PIN_0,GPIO_PIN_0);RIT128x96x4StringDraw("Receive: ", 30,80, 15);RIT128x96x4StringDraw(rxchar, 66,80,15);RIT128x96x4StringDraw(" ", 72,80,15);SysCtlDelay();GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_0,0);*/return 0;/中断处理void SysTick_Handler (void) Event =

32、1;/*中断服务函数ISR*/void GPIO_PORT_D_ISR(void)unsigned char ucKey;unsigned long ulStatus;ulStatus = GPIOPinIntStatus(GPIO_PORTD_BASE, true);GPIOPinIntClear(GPIO_PORTD_BASE, ulStatus);if(ulStatus & GPIO_PIN_7)ucKey = GPIOPinRead(GPIO_PORTC_BASE, GPIO_PIN_4);ucKey = ucKey>>1;ucValue = ucValue + u

33、cKey;ucValue = ucValue<<1;ki+;if(ki=4)ki=0;oledkey1='0'if(ucValue>>4)<10)oledkey0 = (ucValue>>4) + 48;elseoledkey0 = (ucValue>>4) - 10 + 'A' Event_key = 1;void timerset()SysCtlPeripheralEnable(SYSCTL_PERIPH_TIMER0);TimerConfigure(TIMER0_BASE, TIMER_CFG_32_B

34、IT_PER);TimerLoadSet(TIMER0_BASE, TIMER_A, SysCtlClockGet()/100); / 不除以100 则1 秒中断一次IntEnable(INT_TIMER0A);TimerIntEnable(TIMER0_BASE, TIMER_TIMA_TIMEOUT);void Timer0IntHandler(void)unsigned long ulStatus;ulStatus = TimerIntStatus(TIMER0_BASE, true); / 获取当前中断状态TimerIntClear(TIMER0_BASE, TIMER_TIMA_TI

35、MEOUT); / 清除全部中断状态if (ulStatus & TIMER_TIMA_TIMEOUT) / 如果是超时中断/补充该部分代码time+;/每次计时中断，相应计数值进行变化void UARTIntHandler(void)unsigned long uStatus;/ Get the interrrupt status.uStatus = UARTIntStatus(UART0_BASE, true);/ Clear the asserted interrupts.UARTIntClear(UART0_BASE, uStatus);/ Loop while there a

36、re characters in the receive FIFO.while(UARTCharsAvail(UART0_BASE)/ Read the next character from the UART and write it back to the UART.UARTCharPutNonBlocking(UART0_BASE, UARTCharGetNonBlocking(UART0_BASE); void UARTSend(const unsigned char *pucBuffer, unsigned long ulCount)/ Loop while there are mo

37、re characters to send./while(ulCount-)/ Write the next character to the UART./UARTCharPutNonBlocking(UART0_BASE, *pucBuffer+);拓展#include <stdio.h>#include <LM3Sxxxx.H>#include <hw_ints.h>#include <hw_memmap.h>#include <hw_types.h>#include <gpio.h>#include <inte

38、rrupt.h>#include <sysctl.h>#include <uart.h>#include "rit128x96x4.h" /#include "utility.h" #define MAX_SIZE 40 / 缓冲区最大限制长度#define UARTCharGetNB UARTCharGetNonBlockingchar RxBuf1 + MAX_SIZE; / 接收缓冲区int BufP = 0; / 缓冲区位置变量tBoolean RxEndFlag = false; / 接收结束标志unsigned

39、int Event=0,Event_key=0,Send=0,Receive=0;int type=0;int ki=0;char oledkey2;int state=0;unsigned char ucValue=0x00;long time=0;int Speed,count=0;unsigned char rxchar10;void timerset(void);void UARTSend(const unsigned char *pucBuffer, unsigned long ulCount);void recive()if(UARTCharsAvail(UART0_BASE)rx

40、char0 = UARTCharGet(UART0_BASE); / 等待接收字符rxchar1 = '0'GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_0,GPIO_PIN_0);RIT128x96x4StringDraw("Receive: ", 30,80, 15);RIT128x96x4StringDraw(rxchar, 66,80,15);RIT128x96x4StringDraw(" ", 72,80,15);SysCtlDelay();GPIOPinWrite(GPIO_PORTF_BASE

41、, GPIO_PIN_0,0);void send() RIT128x96x4StringDraw("sending1",0,60,15);GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_0,GPIO_PIN_0);SysCtlDelay();/RIT128x96x4StringDraw("sending2",20,1,15);UARTSend(unsigned char *)&rxchar, 1);SysCtlDelay();GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_0,0);i

42、f(rxchar0 >= 0x39) | (rxchar0 < 0x30)rxchar0 = 0x30;elserxchar0+;RIT128x96x4StringDraw("sended ",1,1,15);int main()/声明部分rxchar0=0x30;rxchar1='0'/初始化/* Set the clocking to run from PLL at 50 MHz */SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN | SYSCTL_XTAL_

43、8MHZ);RIT128x96x4Init();RIT128x96x4Clear();/设置时钟中断1SysTickPeriodSet(SysCtlClockGet()/100); SysTickEnable();SysTickIntEnable();/*/设置键盘中断/*使能外设GPIO */SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOC);SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD);SysCtlPeripheralEnab

44、le(SYSCTL_PERIPH_UART0);SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);/*设置GPIO 为输入 */GPIOPinTypeGPIOInput(GPIO_PORTD_BASE, GPIO_PIN_7);GPIOPinTypeGPIOInput(GPIO_PORTC_BASE, GPIO_PIN_4);/*配置GPIO 端口为输出/ 7segd1(PB6);7segd2(PB4);7segd3(PB5)GPIOPinTypeGPIOOutput(

45、GPIO_PORTB_BASE, GPIO_PIN_4 | GPIO_PIN_5 | GPIO_PIN_6);/ bitcode0(PC5);bitcode1(PC6);bitcode2(PC7)GPIOPinTypeGPIOOutput(GPIO_PORTC_BASE, GPIO_PIN_5 | GPIO_PIN_6 | GPIO_PIN_7);/ 7segd0(PD4);7segdot(PD5);rst(PD6)GPIOPinTypeGPIOOutput(GPIO_PORTD_BASE, GPIO_PIN_4 | GPIO_PIN_5 | GPIO_PIN_6);*/*使能中断 */Int

46、Enable(INT_GPIOD);IntMasterEnable();GPIOPinIntEnable(GPIO_PORTD_BASE, GPIO_PIN_7);GPIOIntTypeSet(GPIO_PORTD_BASE, GPIO_PIN_7, GPIO_RISING_EDGE);/*GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_0);GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);/ Configure the UART for 115,200, 8N1 operati

47、on.UARTConfigSetExpClk(UART0_BASE, SysCtlClockGet(), ,(UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE |UART_CONFIG_PAR_NONE);UARTFIFOLevelSet(UART0_BASE, / 设置发送和接收FIFO 深度UART_FIFO_TX4_8,UART_FIFO_RX6_8);IntEnable(INT_UART0);UARTIntEnable(UART0_BASE, UART_INT_RX | UART_INT_RT);timerset();/计时器初始化timerset()

48、;/计时器初始化 RIT128x96x4StringDraw("com1", 0, 0, 15);/显示串口号RIT128x96x4StringDraw("", 0, 20, 15);/显示波特率/*unsigned char a= *pulConfig;char d30;char b30;d=*a+1;b=*a+2;*/RIT128x96x4StringDraw("8", 0, 40, 15);/显示数据位/unsigned long parity=UARTParityModeGet(UART0_BASE);/sprintf(p,&

49、quot;%d",parity );RIT128x96x4StringDraw("wu", 0, 60, 15);/显示校验位RIT128x96x4StringDraw("1", 0, 80, 15);/显示停止位RIT128x96x4StringDraw("E:send",1,31,15);RIT128x96x4StringDraw("F:receiave",1,41,15);while(1) if(Event)Event = 0; if(Event_key)Event_key = 0;switch(o

50、ledkey0)/*case '0':Draw_Char_H(0);break;case '1':Reset_Counter_Speed(128);Speed = 128;break;*/case 'F': state=1;/Receive = 1;/Send = 0;break;case 'E': state=2;/Send = 1;/Receive = 0;break;default:state=0;break; switch(state)case 0:break;case 1: recive();break;fffhhcas

51、e 2:send();break;default:/state=0;break; /*if(Send)RIT128x96x4StringDraw("sending1",0,60,15);GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_0,GPIO_PIN_0);SysCtlDelay();/RIT128x96x4StringDraw("sending2",20,1,15);UARTSend(unsigned char *)&rxchar, 1);SysCtlDelay();GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_0,0);if(rxchar0 >= 0x39) | (rxchar0 < 0x30)rxchar0 = 0x30;elserxchar0+;RIT128x96x4StringDraw("sended ",1,1,15);if(Receive) if(UARTCharsAvail(UART0_BASE)rxchar0 = UARTCharGet(UART0_BASE); / 等待接收字符rxchar1 = '0'GPIOPinWrite(GPIO_PORTF_B