[motu]

Chào cả nhà, dựa theo bài viết trên, e đã viết code cho con pic877a như sau:

#include <16F877A.H>
#include <def_877a.h>
#FUSES NOWDT, HS, PUT, NOPROTECT, NODEBUG, BROWNOUT, NOLVP, NOCPD, NOWRT
#use delay(clock=4000000)
#define PT_MCU_CLOCK          getenv("CLOCK")
#define PT_SPEED              (9600)
#define PT_MAX_FRAME_CHECK    2
#define PT_TX_PIN             PIN_B0
#define PT_RX_PIN             PIN_B1
#define PT_TIMER              (((((PT_MCU_CLOCK/4)/8)/(PT_SPEED/4))))
#define PT_BIT_0              0b00010001
#define PT_BIT_1              0b01110111
#define PT_BIT_F              0b01110001
#define PT_SENDING            0
#define PT_IDLE               1
const char PT_BIT_TABLE[3]={PT_BIT_0,PT_BIT_1,PT_BIT_F};
signed long PT_TX_TIMER = -(PT_TIMER/1);
unsigned long TIME_0a_75_BIT = (float)(PT_TIMER)*(float)0.75;
unsigned long TIME_1a_25_BIT = (float)(PT_TIMER)*(float)1.25;
unsigned long TIME_2a_75_BIT = (float)(PT_TIMER)*(float)2.75;
unsigned long TIME_3a_25_BIT = (float)(PT_TIMER)*(float)3.25;
unsigned long TIME_30a_75_BIT = (float)(PT_TIMER)*(float)30.75;
unsigned long TIME_31a_25_BIT = (float)(PT_TIMER)*(float)31.25;
unsigned long data, addr;
unsigned int Pt2262BuffCurrent, Pt2262BuffCounter, Pt2262LoopCounter;
char PtBuff[16];
int1 PtState;

void Pt2262TxCheck()
   {
    unsigned short b;
    
    if (Pt2262BuffCurrent!=Pt2262BuffCounter)
     {
      b = PtBuff[Pt2262BuffCurrent>>3]>>(Pt2262BuffCurrent&0x07);
      output_bit(PT_TX_PIN,b);
      Pt2262BuffCurrent++;
     }
    if (Pt2262BuffCurrent==Pt2262BuffCounter)
     {
      if (--Pt2262LoopCounter>0)
       {
        Pt2262BuffCurrent=0;
       }
      else
       {
        Pt2262BuffCurrent=0;
        Pt2262LoopCounter = 4;
        output_low(PT_TX_PIN);
        clear_interrupt(INT_EXT);
        enable_interrupts(INT_EXT);
        PtState = PT_IDLE;
       }
     }
   }  
   
#int_timer1
void Timer1_ISR()
   {
    set_timer1(PT_TX_TIMER);
    if(PtState==PT_SENDING)
     {
      Pt2262TxCheck();
     }
    else
     {
      PtState=PT_IDLE;
     }
   } 

void main()
   {
    int i;
    set_tris_b(0b00000010);
    portB=0x00;
    addr = 22222222;
    data = 1111;
    for (i=0;i<8;i++)
     {
      PtBuff[i] = PT_BIT_TABLE[(addr%10)%3];
      addr = addr/10;
     }
    PtBuff[8] = ((data>>3)&0x01)?PT_BIT_1:PT_BIT_0;
    PtBuff[9] = ((data>>2)&0x01)?PT_BIT_1:PT_BIT_0;
    PtBuff[10] = ((data>>1)&0x01)?PT_BIT_1:PT_BIT_0;
    PtBuff[11] = ((data>>0)&0x01)?PT_BIT_1:PT_BIT_0;
    PtBuff[12] = 0b00000001;
    PtBuff[13] = PtBuff[14] = PtBuff[15] = 0b00000000;
    PtState = PT_IDLE;
    enable_interrupts(global);
    enable_interrupts(int_timer1);
    setup_timer_1(T1_INTERNAL | T1_DIV_BY_1);
    set_timer1(PT_TX_TIMER);
    Pt2262BuffCurrent=0;
    Pt2262BuffCounter = 16*8;
    Pt2262LoopCounter = 4;
    while(1)
     {    
      PtState = PT_SENDING;
     }
   }

không biết sai sót chỗ nào mà mạch thu không nhận được tín hiệu, pic dùng thạch anh 4MHz, mạch thu dùng pt2272, Rosc = 820K. Ai giúp e với, thk.