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Timer/counter prescalers – Rainbow Electronics ATmega103L User Manual

Page 35

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ATmega603/103

35

Timer/Counter Prescalers

Figure 28. Prescaler for Timer/Counter 1 and Timer/Counter2

For Timer/Counters 1 and 2, the four different prescaled selections are: CK/8, CK/64, CK/256 and CK/1024 where CK is
the CPU clock. Observe that CPU clock frequency can be lower than the XTAL frequency if the XTAL divider is enabled. For
Timer/Counters 1 and 2, added selections as CK, external source and stop, can be selected as clock sources.

Figure 29. The Timer/Counter0 Prescaler

10-BIT T/C PRESCALER

TIMER/COUNTER2 CLOCK SOURCE

TCK2

TIMER/COUNTER1 CLOCK SOURCE

TCK1

CK

T2

T1

CS20

CS10

CS21

CS11

CS22

CS12

CK/8

CK/256

CK/1024

CK/64

0

0

10-BIT T/C PRESCALER

TIMER/COUNTER0 CLOCK SOURCE

PCK0

CK

PCK0

TOSC1

AS0

CS00

CS01

CS02

PCK0/8

PCK0/64

PCK0/128

PCK0/1024

PCK0/256

PCK0/32