Owner manual

AT90C8534

Timer Counter0 – TCNT0

The Timer/Counter0 is realized as an up-counter with read and write access. If the Timer/Counter0 is written and a clock

source is selected, the Timer/Counter0 continues counting in the timer clock cycle following the write operation.

16-bit Timer/Counter1

Figure 28 shows the block diagram for Timer/Counter1.

The 16-bit Timer/Counter1 can select clock source from CK or prescaled CK. In addition, it can be stopped as described in

the specification for the Timer/Counter1 Control Register – TCCR1. The overflow status flag is found in the Timer/Counter

Interrupt Flag Register – TIFR. Control signals are found in the Timer/Counter1 Control Register – TCCR1. The interrupt

enable/disable setting for Timer/Counter1 is found in the Timer/Counter Interrupt Mask Register – TIMSK.

The 16-bit Timer/Counter1 features both a high resolution and a high accuracy usage with the lower prescaling opportuni-

ties. Similarly, the high prescaling opportunities make the Timer/Counter1 useful for lower speed functions or exact timing

functions with infrequent actions.

Figure 28. Timer/Counter1 Block Diagram

Timer/Counter1 Control Register – TCCR1

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Bits 7..3 – Res: Reserved Bits

These bits are reserved bits in the AT90C8534 and always read zero.

Bit 76543210

$32 ($52) MSB LSB TCNT0

Read/Write R/W R/W R/W R/W R/W R/W R/W R/W

Initial value 0 0 0 0 0 0 0 0

Bit 7 6 5 4 3 2 1 0

$2E ($4E) –– – – –CS12 CS11 CS10 TCCR1

Read/Write R R R R R R/W R/W R/W

Initial value 0 0 0 0 0 0 0 0

8-BIT DA

TA BUS

T/C1 CONTROL

TIMER/COUNTER1

(TCNT1)

015

T/C CLK SOURCE

CONTROL

LOGIC

CS12

CS11

CS10

T/C1 OVER-

FLOW IRQ

TIMER INT. MASK

TOIE0

TOIE1

TIMER INT. FLAG

TOV0

TOV1