Datasheet

103
2586N–AVR–04/11
ATtiny25/45/85
13.3 Register Description
13.3.1 TCCR1 – Timer/Counter1 Control Register
• Bit 7 – CTC1 : Clear Timer/Counter on Compare Match
When the CTC1 control bit is set (one), Timer/Counter1 is reset to $00 in the CPU clock cycle
after a compare match with OCR1A register. If the control bit is cleared, Timer/Counter1 contin-
ues counting and is unaffected by a compare match.
• Bit 6 – PWM1A: Pulse Width Modulator A Enable
When set (one) this bit enables PWM mode based on comparator OCR1A in Timer/Counter1
and the counter value is reset to $00 in the CPU clock cycle after a compare match with OCR1C
register value.
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
Table 13-3. Timer/Counter1 Clock Prescale Select in the Asynchronous Mode (Continued)
PWM Frequency Clock Selection CS1[3:0] OCR1C RESOLUTION
Bit 7 6 5 4 3 2 1 0
0x30 CTC1 PWM1A COM1A1 COM1A0 CS13 CS12 CS11 CS10 TCCR1A
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