ATA8743 ATMEL Corporation, ATA8743 Datasheet - Page 111

• Manufacturer Part Number: ATA8743
• Manufacturer: ATMEL Corporation

9152A–INDCO–07/09
main code and the interrupt code update the temporary register, the main code must disable the
interrupts during the 16-bit access.
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. See
“About Code Examples” on page
(1)
(1)
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