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/*************************************************** Chip type : ATmega8 Program type : Application Clock frequency : 4.000000 MHz Memory model : Small External SRAM size : 0 Data Stack size : 256 ***************************************************/ #include #include #include #define T1OCR1AL 0xCFunsigned char Timer0Counter; //一個脈沖周期溢出的次數(shù) unsigned int T; void InitDevice(void); void InitWork(void); void main(void) { unsigned int Ocr1aValue; delay_ms(500); InitDevice(); Timer0Counter=153; T=39060; while(1) { #asm("wdr") if(T<78)T=78; if(T>=39060)Ocr1aValue=1999; else Ocr1aValue=(long)2000*T/(312+T)-1; OCR1AH=Ocr1aValue>>8; OCR1AL=Ocr1aValue; } } // External Interrupt 1 service routine interrupt [EXT_INT1] void ext_int1_isr(void) { unsigned char data; data=TCNT0;TCNT0=0; T=(unsigned int)Timer0Counter*256+data; Timer0Counter=0; } // Timer 0 overflow interrupt service routine interrupt [TIM0_OVF] void timer0_ovf_isr(void) { #asm("sei") if(Timer0Counter<153)Timer0Counter++; else T=39060; } //**************************************************************************** //初始化程序 void InitDevice(void) { // Input/Output Ports initialization // Port B initialization // Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=Out Func0=In // State7=T State6=T State5=T State4=T State3=T State2=T State1=0 State0=T PORTB=0x00; DDRB=0xFF; // Port C initialization // Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In // State6=T State5=T State4=T State3=T State2=T State1=T State0=T PORTC=0x00; DDRC=0xFF; // Port D initialization // Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In // State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T PORTD=0x00; DDRD=0xF7; // Timer/Counter 0 initialization // Clock source: System Clock // Clock value: 3.906 kHz TCCR0=0x05; TCNT0=0x00; // Timer/Counter 1 initialization // Clock source: System Clock // Clock value: 4000.000 kHz // Mode: Fast PWM top=OCR1A // OC1A output: Toggle // OC1B output: Discon. // Noise Canceler: Off // Input Capture on Falling Edge // Timer 1 Overflow Interrupt: Off // Input Capture Interrupt: Off // Compare A Match Interrupt: Off // Compare B Match Interrupt: Off TCCR1A=0x43; TCCR1B=0x19; TCNT1H=0x00; TCNT1L=0x00; OCR1AH=T1OCR1AH; OCR1AL=T1OCR1AL; // External Interrupt(s) initialization // INT0: Off // INT1: On // INT1 Mode: Rising Edge GICR|=0x80; MCUCR=0x08; GIFR=0x80; // Timer(s)/Counter(s) Interrupt(s) initialization TIMSK=0x01; // Watchdog Timer initialization // Watchdog Timer Prescaler: OSC/2048k #pragma optsize- WDTCR=0x1F; WDTCR=0x0F; #ifdef _OPTIMIZE_SIZE_ #pragma optsize+ #endif // Global enable interrupts #asm("sei") } |
