PIC16F877A 串口使用 屏幕回顯
實(shí)現(xiàn)串口輸出，以及將接收到的信息發(fā)送回。
利用PC機(jī)串口測(cè)試，正常。
kit3、MPLAB X IDE Version 1.85；target PIC16F877A最小系統(tǒng)。
#include
#define uchar unsigned char
#define uint unsigned int
// CONFIG
#pragma config FOSC = HS // Oscillator Selection bits (HS oscillator)
#pragma config WDTE = OFF // Watchdog Timer Enable bit (WDT disabled)
#pragma config PWRTE = OFF // Power-up Timer Enable bit (PWRT disabled)
#pragma config BOREN = ON // Brown-out Reset Enable bit (BOR enabled)
#pragma config LVP = ON // Low-Voltage (Single-Supply) In-Circuit Serial Programming Enable bit (RB3/PGM pin has PGM function; low-voltage programming enabled)
#pragma config CPD = OFF // Data EEPROM Memory Code Protection bit (Data EEPROM code protection off)
#pragma config WRT = OFF // Flash Program Memory Write Enable bits (Write protection off; all program memory may be written to by EECON control)
#pragma config CP = OFF // Flash Program Memory Code Protection bit (Code protection off)
//main.c
void uart_init(void);
void uart_send_byte(char uart_data);
char uart_receive_byte(void);
void delay(void);
/***********************************************/
char uart_current_data;
char uart_last_data;
char evm_info[]="Welcom to use PIC16F877-EVM-BOARD-V1.0";
/*********************************************************************/
void main(void)
{
unsigned char i,j;
TRISB = 0x00+(0x01<<5); //初始化端口B，RB5為輸入口，其余為輸出口
TRISC = 0x80; // bit7 rx input bit6 tx output初始化端口C的方向控制寄存器（
//對(duì)應(yīng)的比特為0是輸出口，比特為1輸入口）
TRISD = 0x00; //初始化D口
TRISE = 0x00; //初始化E口
ADCON1= 0x06; //端口都為數(shù)字口
TRISA = 0x00; //設(shè)置A口均為輸出口
OPTION_REG &= (~(0x01<<7)); //
PORTA = 0xff; //初始化端口寄存器
PORTB = 0xff&(~(0x01<<5));
PORTC = 0xff;
PORTD = 0xff;
PORTE = 0xff;
uart_init(); //初始化PIC16F877串行通訊接口
for(i=0;i<38;i++)
{
uart_send_byte(evm_info[i]);
}
uart_send_byte(0x0d); //將回車鍵第一字符給PC
uart_send_byte(0x0a); //將回車鍵第二字符給PC
for(;;) //程序主循環(huán)
{
uart_current_data=uart_receive_byte(); //接收一個(gè)字符，沒(méi)有收到字符，返回0x00
if( uart_current_data!=0x00 && uart_current_data!=0x0d &&
uart_current_data!=0x0a)
{
uart_send_byte(uart_current_data); //將字符發(fā)回PC
uart_last_data=uart_current_data; //暫存當(dāng)前的字符
}
else if(uart_current_data==0x0d) //回車鍵字符判斷？
{
uart_last_data=uart_current_data; //暫存回車鍵字符第一字符
}
else if(uart_current_data==0x0a && uart_last_data==0x0d)//收到了正
//確的回車鍵？
{
uart_send_byte(0x0d); //將回車鍵第一字符給PC
uart_send_byte(0x0a); //將回車鍵第二字符給PC
uart_last_data=0x00;
}
}
}
/************************************************/
void delay(void)
{
unsigned int i;
for(i=0;i<500;i++);
}
void interrupt isr_service(void) //中斷服務(wù)程序
{
if(T0IE && T0IF)
{
T0IF = 0; //在此加入TMR0中斷服務(wù)
}
if (TMR1IE && TMR1IF) //判TMR1中斷
{
TMR1IF=0; //在此加入TMR1中斷服務(wù)
}
} //中斷結(jié)束并返回
/************************************************/
void uart_init(void)
{
SPBRG=0x4d; //設(shè)置通訊波特率為9600/秒
SPEN=1; //1 = Serial port enabled (configures RC7/RX/DT and
// RC6/TX/CK pins as serial port pins)
RX9=0; //0 = Selects 8-bit reception
SYNC=0; //Asynchronous mode
BRGH=1; //1 = High speed
TX9=0; //0 = Selects 8-bit transmission
TXEN=1; //1 = Transmit enabled
CREN=1;
}
/***********************************************/
void uart_send_byte(char uart_data)
{
TXREG=uart_data;
while(1)
{ //等待發(fā)送完畢
if(TRMT==1) break ; // 使用if(TXIF == 1) break 時(shí)，會(huì)導(dǎo)致發(fā)送數(shù)據(jù)的丟失
}
}
/***********************************************/
char uart_receive_byte(void)
{
char result=0;
if(RCIF==1) //判是否收到了數(shù)據(jù)？
{
result=RCREG; //讀取接收到的數(shù)據(jù)
}
return(result);
}
/***********************************************/
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