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我基本上是在pic16f84a微控制器上學習pic外部中斷。基本上我想每按一次按鈕連接到引腳B0(RB0/T0CKI)並顯示七段顯示結果。我正在使用hitech c編譯器。pic 16f84a定時器/計數代碼沒有像預期的那樣運行
#include<htc.h>
__CONFIG(WDTE_OFF& PWRTE_OFF & CP_OFF);
char get7SegmentCode(char value)
{
switch(value)
{
case 0b00000000:
return (char)0b00111111 ; //0 code
case 0b00000001:
return (char)0b00110000 ; //1 code
case 0b00000010:
return (char)0b01011011 ; //2 code
case 0b00000011:
return (char)0b010011111 ; //3 code
default:
return (char)0b00000000 ; //all code
}
}
void main()
{
//declare portb for output and porta upper 4 pins for output and lower 4 for input
TRISA=0b00001111;
TRISB=0b00000000;
CLRWDT();//clear watchdog timer
TMR0=0;
OPTION_REG = 0b00111000;//RBPU:PORTB pull-ups are disabled,
//INTEDG:Interrupt on falling edge of RB0/INT pin
//T0CS:Transition on RA4/T0CKI pin
//T0SE:Increment on high-to-low transition on RA4/T0CKI pin
//PSA:Prescaler assigned to the WDT
while(1)
{
char timerval= TMR0;//read tmr0 into variable
char restrictedtimerval= timerval & 0x0f;//force upper 4bits to zero to restrict value to 0 - f
PORTB= get7SegmentCode(restrictedtimerval);
}
}
不幸的是,當我在變形VSM模擬這個代碼,七段顯示器只顯示「0」,無論多少次,我按下開關。這是爲什麼發生? PS:這是我的電路。