avr利用pwm控制led光暗和蜂鸣器.doc

//ICC-AVR燼pplication燽uilder?/燭arget?燤16? //燙rystal:?.0000Mhz? #include?iom16v.h? #include?macros.h? #define爑char爑nsigned燾har #define爑int爑nsigned爄nt void爌ort_init(void); void爐imer0_init(void); void爄nit_devices(void); void燿elay_short(uint爐); uchar爏can_key(void); void爌ort_init(void)? {? 燩ORTA??x00;? 燚DRA牋=?x00;? 燩ORTB?燘IT(PB3);? 燚DRB牋=燘IT(PB3);? 燩ORTC??x00;?/m103爋utput爋nly? 燚DRC牋=?x00;? 燩ORTD??x00;? 燚DRD牋=?x00;? }? //燱GM:燩WM燩hase?correct //?desired?value:?1KHz //?actual?value:??0.980KHz?(-2.0%) void?timer0_init(void)? {? ?TCCR0?=?0x00;?//stop? ?TCNT0?=?0x01;?//set?count? ?OCR0??=?0xFF;??//set?compare? ?TCCR0?=?0x62;?//start?timer?;?相位修正,?8分頻 }? //call?this?routine?to?initialize燼ll爌eripherals? void爄nit_devices(void)? {? ?/stop爀rrant爄nterrupts爑ntil爏et爑p? 燙LI();?/disable燼ll爄nterrupts? 爌ort_init();? 爐imer0_init();? 燤CUCR??x00;? 燝ICR牋=?x00;? 燭IMSK??x00;?/timer爄nterrupt爏ources? 燬EI();?/re-enable爄nterrupts? ?/all爌eripherals燼re爊ow爄nitialized? } void燿elay_short(uint爐)?/?短延時 { ??uint?i; ??for?(i=0;it;i++); } uchar?scan_key(void)??//?按鍵掃瞄 {? ??uchar?v; ?? ??v?=?0;????? ?? ??if?((PIND??0x07)?!=?0x07) ??{ ? ??if?((PIND??0x01)?==?0)? ??{ ???v?=?1; ????delay_short(1000);?? ??} ?? ??if?((PIND??0x2)?==?0)? ??{ ????v?=?2; ????delay_short(1000);?? ??} ??? ??if?((PIND??0x4)?==?0)? ??{ ????v?=?3; ????delay_short(1000);?? ??} ??}; ??while((PIND??0x07)?!=?0x07);???//?判斷按鍵是不是放開??? ??return?v;?? } void?main(void)? {?? ?uchar?key,?OCR0_V; ? ?init_devices();? ?OCR0_V?=?0xff; ? ?while(1) ?{ ???key?=?scan_key(); ??? ???if?(key??0) ???{ ?????if?(key==1)?//?減少佔空比 ????{? ??????OCR0_V?-=?10; ??????OCR0?=?OCR0_V; ????}; ???? ?????if?(key==2)?//?增加佔空比 ????{? ??????OCR0_V?+=?10; ??????OCR0?=?OCR0_V; ????};???? ???? ?????if?(key==3)?//?全黑,佔空比為100%? ????{? ??????OCR0_V?=?0xff; ??????OCR0?=?OCR0_V; ????};??????