[duyldb]

tình hình em đang làm mạch pic18f4431 giao tiếp với SFR05 đo khoảng cách sau đó hiển thị lên LCD 16x2, nhưng em đang gặp rắc rối ở phần đo thời gian nhận xung phản hồi từ chân ECHO, đây là code của em, mọi người xem giúp e sai chỗ nào

#include <18F4431.h>
#FUSES NOWDT, NOPUT, HS, NOPROTECT, NODEBUG, NOBROWNOUT, NOLVP, NOCPD, NOWRT
#use delay(clock=8000000)
#define LCD_EN PIN_D3
#define LCD_RS PIN_D1
#define LCD_RW PIN_D2
#define LCD_D4 PIN_D4
#define LCD_D5 PIN_D5
#define LCD_D6 PIN_D6
#define LCD_D7 PIN_D7
#define TRIGGER PIN_C0
#define ECHO PIN_C1
float dist,getvar;
int1 has_echo=0;
#int_TIMER1
void TIMER1_isr(void)
{
has_echo = 1;
dist = -1;
}

#int_CCP2
void CCP2_isr(void)
{
if(pin_c1)
{ // Neu là xung canh lên
set_timer1(0); // Reset timer1 ve 0
setup_ccp2(CCP_CAPTURE_FE); // Chuyen Capture 1 do canh xuong
}
if(!pin_c1) { // Neu là xung canh xuong
getvar=CCP_2;// Ðoc giá tri timer 1
dist=(getvar*2)/58; // Moi 1 nhip cua timer 0 tuong ung vs 2 us, lay us chia cho 58 ra cm
setup_ccp2(CCP_CAPTURE_RE); // Chuyen Capture 1 do xung lên tro lai
has_echo = 1; // Ðã nhan xong echo
}
}


//----15us cho trigger----
void trig()
{
output_high(TRIGGER);
delay_us(15);
output_low(TRIGGER);
}
//Tao Xung
void LCD_Enable(void)
{
output_high(LCD_EN);
delay_us(10);
output_low(LCD_EN);
delay_us(10);
}
//Ham Gui 4 Bit Du Lieu Ra LCD
void LCD_Send4Bit( unsigned char Data )
{
output_bit(LCD_D4,Data&0x01);
output_bit(LCD_D5,(Data>>1)&1);
output_bit(LCD_D6,(Data>>2)&1);
output_bit(LCD_D7,(Data>>3)&1);
}
// Ham Gui 1 Lenh Cho LCD
void LCD_SendCommand (unsigned char command )
{
LCD_Send4Bit ( command >>4 );/* Gui 4 bit cao */
LCD_Enable () ;
LCD_Send4Bit ( command ); /* Gui 4 bit thap*/
LCD_Enable () ;
}
// Ham Khoi Tao LCD
void LCD_Init ( void )
{
output_drive(LCD_D4);
output_drive(LCD_D5);
output_drive(LCD_D6);
output_drive(LCD_D7);
output_drive(LCD_EN);
output_drive(LCD_RS);
output_drive(LCD_RW);
LCD_Send4Bit(0x00);
delay_us(100);
output_low(LCD_RS);
output_low(LCD_RW);
LCD_Send4Bit(0x03);
LCD_Enable();
delay_us(500);
LCD_Enable();
delay_us(50);
LCD_Enable();
LCD_Send4Bit(0x02);
LCD_Enable();
LCD_SendCommand( 0x28 ); // giao thuc 4 bit, hien thi 2 hang, ki tu 5x8
LCD_SendCommand( 0x0c); // cho phep hien thi man hinh
LCD_SendCommand( 0x06 ); // tang ID, khong dich khung hinh
LCD_SendCommand( 0x01 ); // xoa toan bo khung hinh
}
void LCD_Gotoxy(unsigned char x, unsigned char y)
{
unsigned char address;
if(!y)
address = (0x80+x);
else
address = (0xC0+x);
delay_us(500);
LCD_SendCommand(address);
delay_us(50);
}
// Ham Xoa Man Hinh LCD
void LCD_Clear()
{
LCD_SendCommand(0x01);
delay_ms(10);
}
// Ham Gui 1 Ki Tu Len LCD
void LCD_PutChar ( unsigned char Data )
{
output_high(LCD_RS);
LCD_SendCommand( Data );
output_low(LCD_RS);
}
void LCD_Puts (char *s)
{
while (*s)
{
LCD_PutChar(*s);
s++;
}
}

void main()
{

set_tris_B(0x00);
SET_TRIS_C(0xff);
output_bit(pin_D3,1);
output_bit(pin_D1,1);
LCD_init();
setup_timer_1(T1_INTERNAL|T1_DIV_BY_4); //32.7 ms overflow
setup_ccp2(CCP_CAPTURE_RE); // Thiet lap Capture 1 do canh lên
enable_interrupts(INT_TIMER1);
enable_interrupts(INT_CCP2);
enable_interrupts(GLOBAL);

While (TRUE)
{
has_echo = 0; // Xác lap lai echo
trig(); // Trigger
while (has_echo == 0) { } // cho den khi nhan het echo
lcd_gotoxy(2,0);
printf(lcd_putchar,"dist=%6.1f",dist);
lcd_putchar("cm");
delay_ms(100); // 0.1 s do mot lan
}