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Timer/counter interrupt flag register – tifr – Rainbow Electronics AT90S2313 User Manual

Page 24

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AT90S2313

0839I–AVR–06/02

• Bit 3 – 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 $003) is executed if a capture-triggering event occurs on PD6(ICP) (i.e., when
the ICF1 bit is set in the Timer/Counter Interrupt Flag Register [TIFR]).

• Bit 2 – Res: Reserved Bit

This bit is a reserved bit in the AT90S2313 and always reads as zero.

• Bit 1 – 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
$006) 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]).

• Bit 0 – Res: Reserved Bit

This bit is a reserved bit in the AT90S2313 and always read as zero.

Timer/Counter Interrupt FLAG
Register – TIFR

• Bit 7 – TOV1: Timer/Counter1 Overflow Flag

The TOV1 is set (one) when an overflow occurs in Timer/Counter1. TOV1 is cleared by
hardware when executing the corresponding interrupt handling vector. Alternatively,
TOV1 is cleared by writing a logical “1” to the flag. When the I-bit in SREG and TOIE1
( T i m e r / C o u n te r1 O v e r f l o w In t e rr u p t En a b l e ) a n d T O V 1 a re s e t ( o n e ) , t h e
Timer/Counter1 Overflow Interrupt is executed. In PWM mode, this bit is set when
Timer/Counter1 changes counting direction at $0000.

• Bit 6 – OCF1A: Output Compare Flag 1A

The OCF1A bit is set (one) when a compare match occurs between the Timer/Counter1
and the data in OCR1A (Output Compare Register1 A). OCF1A is cleared by hardware
when executing the corresponding interrupt handling vector. Alternatively, OCF1A is
cleared by writing a logical “1” to the flag. When the I-bit in SREG and OCIE1A
(Timer/Counter1 Compare Match Interrupt Enable) and the OCF1A are set (one), the
Timer/Counter1 Compare Match Interrupt is executed.

• Bits 5, 4 – Res: Reserved Bits

These bits are reserved bits in the AT90S2313 and always read as zero.

• Bit 3 – ICF1: Input Capture Flag 1

T h e ICF 1 bi t is se t (on e) to fla g a n i np ut ca ptu re e ven t, in di cati ng that th e
Timer/Counter1 value has been transferred to the Input Capture Register (ICR1). ICF1
is cleared by hardware when executing the corresponding interrupt handling vector.
Alternatively, ICF1 is cleared by writing a logical “1” to the flag. When the SREG I-bit
and TICIE1 (Timer/Counter1 Input Capture Interrupt Enable) and ICF1 are set (one), the
Timer/Counter1 Capture Interrupt is executed.

Bit

7

6

5

4

3

2

1

0

$38 ($58)

TOV1

OCF1A

ICF1

TOV0

TIFR

Read/Write

R/W

R/W

R

R

R/W

R

R/W

R

Initial value

0

0

0

0

0

0

0

0