German VersionYou could use this this circuit circuit to obtain a very small PCB that can be used nearly everywhere.
To download the Source Code, follow this link.
The Program is very straightforward, but some of the techniques shown can be ust in larger projects.
Reading of the EEPROM
Timer-Interrupt
Software-Counter
The Main Loop only generates a Software PWM Signal.
The Timer Interrupt changes the brightnes between a minimum and a maximum, with different speed, creating a very realistic Heartbeat effect!
Program developed with AVR Studio 4.10.
When programming, store the OSCCAL-Value in EEPROM-Cell $3f !
| ;Hearbeat LED ;(C) 2004 Markus Vohburger ;Gewerbliche Nutzung untersagt. ; ;Registerdefinitionen für Tiny12 ladan .include "tn12def.inc" .def temp1 = r16 .def temp2 = r17 .def output = r18 ;Software-Zähler .def swcount = r19 .def output = r20 ;Zähler für PWM .def pwmcount = r21 ;Richtung heller oder dunkler .def direction = r25 ;Wert für PWM .def pwmvalue = r27 ;Kalibrierbyte für internen Oszillator ist in EEPROM $3f gespeichert .equ EE_OSCCAL= $3f; ;reset-Vektor .org $0000 rjmp main ;Timer 0 Overflow Interrupt Vektor ;timer overflow interrut handler .org OVF0Addr rjmp OVF0Handler ;Hauptprogramm beginnt hier .org $0010 main: ;set internal osc cal ldi temp1,EE_OSCCAL rcall readeeprom out osccal,temp1 ;Ports Setup ldi temp1,$1f out ddrb,temp1 ldi temp1,$1f out portb,temp1 clr pwmcount clr pwmvalue clr direction ;Timer zurücksetzen clr temp1 out tcnt0,temp1 ;Timer interrupts an ldi temp1,(1<<toie0) out timsk,temp1 ;Timer starten ldi temp1,$02 out tccr0,temp1 ldi swcount,0 sei ;hauptschleife, implementiert die PWM loop: ;leds aus ldi output,$1f check_value: cp pwmvalue,pwmcount brsh writeoutput ;leds an (PB0 bis PB2) andi output,$18 writeoutput: out portb,output inc pwmcount rjmp loop ;subroutine zum Lesen aus EEprom readeeprom: sbic eecr,eewe rjmp readeeprom out eear,temp1 in temp1,eedr ret ;Timer 0 Interrupthandler OVF0Handler: ;statusregister sichern in r1,sreg ;Softwarezähler erhöhen inc swcount cpi swcount,$04 brlo exit_ovf0handler clr swcount cpi direction,$00 breq dodec ;pwmwert erhöhen doinc: inc pwmvalue cpi pwmvalue,$80 brlo exit_ovf0handler clr direction ldi pwmvalue,$80 rjmp exit_ovf0handler ;pwmwert verringern ;das Verringern geschieht doppelt so schnell wie das Erhöhen, um den Effekt zu verbessern dodec: dec pwmvalue dec pwmvalue cpi pwmvalue,$01 brsh exit_ovf0handler ldi pwmvalue,$01 ldi direction,$01 ;ende der Timer 0 Interrupt Routine exit_ovf0Handler: out sreg,r1 reti |
Additional Information,Basics,DIY Kit, Links for Schematic
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