Datasheet

113
ATmega169A/PA/329A/PA/649A/P/3290A/PA/6490A/P [DATASHEET]
8284E–AVR–02/2013
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: 1. See ”About code examples” on page 11.
The assembly code example returns the TCNT1 value in the r17:r16 register pair.
Assembly code example
(1)
TIM16_ReadTCNT1:
; 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
C code example
(1)
unsigned int TIM16_ReadTCNT1(void)
{
unsigned char sreg;
unsigned int i;
/* Save global interrupt flag */
sreg = SREG;
/* Disable interrupts */
__disable_interrupt();
/* Read TCNT1 into i */
i = TCNT1;
/* Restore global interrupt flag */
SREG = sreg;
return i;
}