Rainbow-electronics ATmega8515L Manuel d'utilisateur télécharger pdf (Page 98)

ATmega8515(L)

2512A–AVR–04/02

The following codeexamplesshowhow to doanatomicread of theTCNT1 Register

contents.Reading any of the OCR1A/B orICR1 Registers can be done by using the

same principle.

Note: 1. Theexample codeassumes that the part specificheaderfileis included.

Theassembly codeexample returns theTCNT1 value in the r17:r16registerpair.

Assembly Code Example

(1)

TIM16_ReadTCNT1:

;

Save global interrupt flag

in r18,SREG

;

Disable interrupts

cli

; Read TCNT

1 into r17:r16

in r16,TCNT

in r17,TCNT

;

Restore global interrupt flag

out SREG,r18

ret

CCode Example

(1)

unsigned int TIM16_ReadTCNT1( void )

{

unsigned char sreg;

unsigned int i;

Save global interrupt flag

sreg = SREG;

Disable interrupts

_CLI();

Read TCNT

into i

i = TCNT

Restore global interrupt flag

SREG = sreg;

return i;

}

1 2 ... 93 94 95 96 97 98 99 100 101 102 103 ... 222 223

Pas de commentaire

Rainbow-electronics ATmega8515L Manuel d'utilisateur Page 98