PIC16F877AでUSART （GT-720Fをつなぐ）

#include <pic.h>
#include "lcdlib16.h"

__CONFIG(XT & WDTDIS & PWRTEN & BOREN & LVPDIS & UNPROTECT);

#define FOSC		4000000
#define BAUDRATE	9600
#define NINE_MODE	0
#define SYNC_MODE	0	// 0=非同期, 1=同期
#define HIGHT_SPEED	1	// 0=低速, 1=高速
#if (HIGHT_SPEED == 1)
#define SPBRG_VAL 25 //(FOSC/(16 * BAUDRATE))-1
#else
#define SPBRG_VAL (FOSC/(64 * BAUDRATE)-1)
#endif
#define SEND_ENABLE
#define RECIVE_ENABLE
#define USART_INTERRUPT
// 送信バッファ
#define SND_BUFF_SIZE	16
unsigned char SND_BUFF_START = 0;
unsigned char SND_BUFF_INDEX = 0;
unsigned char SND_BUFF[SND_BUFF_SIZE];
// 受信バッファ
#define RCV_BUFF_SIZE	16
unsigned char RCV_BUFF_START = 0;
unsigned char RCV_BUFF_INDEX = 0;
unsigned char RCV_BUFF[RCV_BUFF_SIZE];

#ifdef USART_INTERRUPT
void interrupt usart_itr()
{
#ifdef SEND_ENABLE
	if (TXIF) {	// 送信で割り込み発生
		if (SND_BUFF_START != SND_BUFF_INDEX) {
			TXREG = SND_BUFF[SND_BUFF_START];
			__delay_ms(1);
			SND_BUFF_START++;
			if (SND_BUFF_START == SND_BUFF_SIZE) {
				SND_BUFF_START = 0;
			}
		}
		if (SND_BUFF_START == SND_BUFF_INDEX) {
			TXEN = 0;
		}
		TXIF = 0;
	}
#endif
#ifdef RECIVE_ENABLE
	if (RCIF) {	// 受信で割り込み発生
		RCV_BUFF[RCV_BUFF_INDEX] = RCREG;
		RCV_BUFF_INDEX++;
		if (RCV_BUFF_INDEX == RCV_BUFF_SIZE) {
			RCV_BUFF_INDEX = 0;
		}
		RCIF = 0;
	}
#endif
}
#endif

#ifdef RECIVE_ENABLE
unsigned char getch()
{
	while (RCV_BUFF_START == RCV_BUFF_INDEX) {
		// wait
	}
	unsigned char rcv;
	rcv = RCV_BUFF[RCV_BUFF_START];
	RCV_BUFF_START++;
	if (RCV_BUFF_START == RCV_BUFF_SIZE) {
		RCV_BUFF_START = 0;
	}
	return rcv;
}
#endif

#ifdef SEND_ENABLE
void putch(unsigned char ch)
{
	if ((SND_BUFF_START == 0) && (SND_BUFF_INDEX == SND_BUFF_SIZE - 1)) {
		// バッファフル
		while ((SND_BUFF_START == 0) && (SND_BUFF_INDEX == SND_BUFF_SIZE - 1)) {
			// wait
		}
	} else if (SND_BUFF_START == SND_BUFF_INDEX + 1) {
		// バッファフル
		while (SND_BUFF_START == SND_BUFF_INDEX + 1) {
			// wait
		}
	}
	SND_BUFF[SND_BUFF_INDEX] = ch;
	SND_BUFF_INDEX++;
	if (SND_BUFF_INDEX == SND_BUFF_SIZE) {
		SND_BUFF_INDEX = 0;
	}
	TXEN = 1;
}
#endif

void main()
{
	// ポートの設定 (LCD用)
	ADCON1 = 0x06;	// ポートAをデジタルへ
	TRISA = 0x00;	// 全部出力
	// USARTの設定
	SPBRG = SPBRG_VAL;
	BRGH = HIGHT_SPEED;
	TX9 = NINE_MODE;
	SYNC = SYNC_MODE;
	SPEN = 1;	// Serial Port ENable
#ifdef USART_INTERRUPT
#ifdef SEND_ENABLE
	TXIE = 1;
#endif
#ifdef RECIVE_ENABLE
	RCIE = 1;
#endif
	PEIE = 1;
	GIE = 1;
#endif
#ifdef RECIVE_ENABLE
	CREN = 1;
#endif
	// LCD初期化
	lcd_init();
	lcd_clear();
	lcd_str("Hello World!");
	for (char i = 0; i < 10; i++) {
		__delay_ms(100);
	}
	lcd_clear();

	unsigned char data;
	data = getch();
	while (1) {
		//putch(data);
		if (data == '\r') {
			//putch('\n');
		} else if (data == '\n') {
		} else if (data < 0x20) {
		} else {
			if (data == '$') {
				lcd_clear();
			}
			lcd_data(data);
		}
		data = getch();
	}
}

	unsigned char data;
	data = getch();
	while (1) {
		putch(data);
		if (data == '\r') {
			putch('\n');
			lcd_clear();
		} else if (data == '\n') {
		} else if (data < 0x20) {
		} else {
			lcd_data(data);
		}
		data = getch();
	}