Timer/counter interrupt flag register – tifr – Rainbow Electronics AT90LS8535 User Manual

Page 27

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AT90S/LS8535

1041H–11/01

• Bit 5 – TICIE1: Timer/Counter1 Input Capture Interrupt Enable

When the TICIE1 bit is set (one) and the I-bit in the Status Register is set (one), the
Timer/Counter1 Input Capture Event Interrupt is enabled. The corresponding interrupt
(at vector $005) is executed if a capture-triggering event occurs on pin 20, PD6 (ICP)
(i.e., when the ICF1 bit is set in the Timer/Counter Interrupt Flag Register [TIFR]).

• Bit 4 – OCIE1A: Timer/Counter1 Output CompareA Match Interrupt Enable

When the OCIE1A bit is set (one) and the I-bit in the Status Register is set (one), the
Timer/Counter1 CompareA Match interrupt is enabled. The corresponding interrupt (at
vector $006) is executed if a CompareA match in Timer/Counter1 occurs (i.e., when the
OCF1A bit is set in the Timer/Counter Interrupt Flag Register [TIFR]).

• Bit 3 – OCIE1B: Timer/Counter1 Output CompareB Match Interrupt Enable

When the OCIE1B bit is set (one) and the I-bit in the Status Register is set (one), the
Timer/Counter1 CompareB Match interrupt is enabled. The corresponding interrupt (at
vector $007) is executed if a CompareB match in Timer/Counter1 occurs (i.e., when the
OCF1B bit is set in the Timer/Counter Interrupt Flag Register [TIFR]).

• Bit 2 – TOIE1: Timer/Counter1 Overflow Interrupt Enable

When the TOIE1 bit is set (one) and the I-bit in the Status Register is set (one), the
Timer/Counter1 Overflow Interrupt is enabled. The corresponding interrupt (at vector
$008) is executed if an overflow in Timer/Counter1 occurs (i.e., when the TOV1 bit is set
in the Timer/Counter Interrupt Flag Register [TIFR]).

• Bit 1 – Res: Reserved Bit

This bit is a reserved bit in the AT90S8535 and always reads zero.

• Bit 0 – TOIE0: Timer/Counter0 Overflow Interrupt Enable

When the TOIE0 bit is set (one) and the I-bit in the Status Register is set (one), the
Timer/Counter0 Overflow Interrupt is enabled. The corresponding interrupt (at vector
$009) is executed if an overflow in Timer/Counter0 occurs (i.e., when the TOV0 bit is set
in the Timer/Counter Interrupt Flag Register [TIFR]).

Timer/Counter Interrupt Flag
Register – TIFR

• Bit 7 – OCF2: Output Compare Flag 2

The OCF2 bit is set (one) when compare match occurs between the Timer/Counter2
and the data in OCR2 (Output Compare Register2). OCF2 is cleared by hardware when
executing the corresponding interrupt handling vector. Alternatively, OCF2 is cleared by
writing a logical “1” to the flag. When the I-bit in SREG and OCIE2 (Timer/Counter2
Compare Match Interrupt Enable) and the OCF2 are set (one), the Timer/Counter2
Compare Match Interrupt is executed.

• Bit 6 – TOV2: Timer/Counter2 Overflow Flag

The TOV2 bit is set (one) when an overflow occurs in Timer/Counter2. TOV2 is cleared
by hardware when executing the corresponding interrupt handling vector. Alternatively,
TOV2 is cleared by writing a logical “1” to the flag. When the SREG I-bit and TOIE2
(T i m e r / C o u n t e r 2 O v e rf l o w I n t e rr u p t E n a b l e ) a n d T OV 2 a r e s e t ( o n e ), t h e
Timer/Counter2 Overflow Interrupt is executed. In up/down PWM mode, this bit is set
when Timer/Counter1 advances from $0000.

Bit

7

6

5

4

3

2

1

0

$38 ($58)

OCF2

TOV2

ICF1

OCF1A

OCF1B

TOV1

TOV0

TIFR

Read/Write

R/W

R/W

R/W

R/W

R/W

R/W

R

R/W

Initial Value

0

0

0

0

0

0

0

0

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