[namqn]

Bạn thử như sau xem sao:

#include <16F877a.h>
#fuses HS,NOWDT,NOPROTECT,NOLVP
#use delay(clock=20000000)
#use rs232(baud=4800, xmit=PIN_C6, rcv=PIN_C7)
#include <def_877a.h>

unsigned char data;

#INT_RDA
void data_receive(void)
{
	data = getc();
}
void main()
{
	set_tris_d(0);
	ENABLE_INTERRUPTS(GLOBAL);
	ENABLE_INTERRUPTS(INT_RDA);
	while(true)
	{
		output_d(data);
		putc(data);
		delay_ms(2000);
	}
}

Thân,