ATTINY25_07 Datasheet, PDF (90/201 Pages) ATMEL Corporation – 8-bit Microcontroller with 2/4/8K Bytes In-System Programmable Flash

Resolution shows how many bit is required to express the value in the OCR1C register. It is cal-
culated by following equation
Resolution_PWM = log₂(OCR1C + 1).
Table 14-6. Timer/Counter1 Clock Prescale Select in the Asynchronous Mode
PWM Frequency
Clock Selection
CS13..CS10
OCR1C
RESOLUTION
20 kHz
PCK/16
0101
199
7.6
30 kHz
PCK/16
0101
132
7.1
40 kHz
PCK/8
0100
199
7.6
50 kHz
PCK/8
0100
159
7.3
60 kHz
PCK/8
0100
132
7.1
70 kHz
PCK/4
0011
228
7.8
80 kHz
PCK/4
0011
199
7.6
90 kHz
PCK/4
0011
177
7.5
100 kHz
PCK/4
0011
159
7.3
110 kHz
PCK/4
0011
144
7.2
120 kHz
PCK/4
0011
132
7.1
130 kHz
PCK/2
0010
245
7.9
140 kHz
PCK/2
0010
228
7.8
150 kHz
PCK/2
0010
212
7.7
160 kHz
PCK/2
0010
199
7.6
170 kHz
PCK/2
0010
187
7.6
180 kHz
PCK/2
0010
177
7.5
190 kHz
PCK/2
0010
167
7.4
200 kHz
PCK/2
0010
159
7.3
250 kHz
PCK
0001
255
8.0
300 kHz
PCK
0001
212
7.7
350 kHz
PCK
0001
182
7.5
400 kHz
PCK
0001
159
7.3
450 kHz
PCK
0001
141
7.1
500 kHz
PCK
0001
127
7.0
15. 8-bit Timer/Counter1 in ATtiny15 Mode
The ATtiny15 compatibility mode is selected by writing the code “0011” to the CKSEL fuses (if
any other code is written, the Timer/Counter1 is working in normal mode). When selected the
ATtiny15 compatibility mode provides an ATtiny15 backward compatible prescaler and
Timer/Counter. Furthermore, the clocking system has same clock frequencies as in ATtiny15.
90 ATtiny25/45/85 Auto
7598D–AVR–02/07