ATMEGA8L ATMEL [ATMEL Corporation], ATMEGA8L Datasheet - Page 78

• Manufacturer Part Number: ATMEGA8L
• Description: 8-bit AVR with 8K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

78
ATmega8(L)
The following code examples show how to do an atomic read of the TCNT1 Register
contents. Reading any of the OCR1A/B or ICR1 Registers can be done by using the
same principle.
Note:
The assembly code example returns the TCNT1 value in the r17:r16 Register pair.
Assembly Code Example
C Code Example
TIM16_ReadTCNT1:
unsigned int TIM16_ReadTCNT1( void )
{
}
; Save Global Interrupt Flag
in r18,SREG
; Disable interrupts
cli
; Read TCNT1 into r17:r16
in r16,TCNT1L
in r17,TCNT1H
; Restore Global Interrupt Flag
out SREG,r18
ret
unsigned char sreg;
unsigned int i;
/* Save Global Interrupt Flag */
sreg = SREG;
/* Disable interrupts */
_CLI();
/* Read TCNT1 into i */
i = TCNT1;
/* Restore Global Interrupt Flag */
SREG = sreg;
return i;
1. The example code assumes that the part specific header file is included.
(1)
(1)
2486M–AVR–12/03