Timer2 mega8

Setzt Du denn mit SEI das Globale Interrupt-Enable-Flag?
Ohne dem passiert gar nix.

ja, mache ich

// Timer/Counter 2 initialization
// Clock source: System Clock
// Clock value: 250,000 kHz
// Mode: Normal top=FFh
// OC2 output: Disconnected
ASSR=0x00;
TCCR2=0x03;
TCNT2=0x00;
OCR2=0x00;

.cseg
 rjmp RESET ; Reset Handler
 reti ;EXT_INT0 ; IRQ0 Handler
 reti ;EXT_INT1 ; IRQ1 Handler
 reti ;TIM2_COMP ; Timer2 Compare Handler
 rjmp  TIM2_OVF ; Timer2 Overflow Handler
 reti ;TIM1_CAPT ; Timer1 Capture Handler
 reti ;TIM1_COMPA ; Timer1 CompareA Handler
 reti ;TIM1_COMPB ; Timer1 CompareB Handler
 reti ;TIM1_OVF ; Timer1 Overflow Handler
 reti ;TIM0_OVF; Timer0 Overflow Handler
 reti ;SPI_STC ; SPI Transfer Complete Handler
 reti ;USART_RXC ; USART RX Complete Handler
 reti ;USART_UDRE ; UDR Empty Handler
 reti ;USART_TXC ; USART TX Complete Handler
 reti ;ADC ; ADC Conversion Complete Handler
 reti ;EE_RDY ; EEPROM Ready Handler
 reti ;ANA_COMP ; Analog Comparator Handler
 reti ;TWSI ; Two-wire Serial Interface
 reti ;SPM_RDY ; Store Program Memory Ready

 ; dann lautet die formel (Xtal/prescaler)*256

RESET:                        ;hier beginnt das Hauptprogramm


   ldi temp, LOW(RAMEND); STACK einstellen
    out SPL, temp
    ldi temp, HIGH(RAMEND)
    out SPH, temp


;   ldi temp, 0b00000001; TOIE0 \"1\" Timer0 Overflow enable
;   out TIMSK, temp


;   ldi temp, 0b00000101; Prescaler 64 CS00 und CS01 \"1\"
;   out TCCR0, temp


   ; ################################



  ldi temp, 0x00
  out ASSR, temp

  ldi temp, 0x07
  out TCCR2, temp

  ldi temp, 0x00
  out TCNT2, temp

  ldi temp, 0x00
  out OCR2, temp


  sei; Interrupts aktivieren

// Timer(s)/Counter(s) Interrupt(s) initialization
TIMSK=0x40;

Das ist wichtig !

Ich habs gemerkt


Danke