Datasheet

118
8197C–AVR–05/11
ATtiny261A/461A/861A
• Bit 3 – FPAC1: Fault Protection Analog Comparator Enable
When written logic one, this bit enables the Fault Protection function in Timer/Counter1 to be
triggered by the Analog Comparator. The comparator output is in this case directly connected to
the Fault Protection front-end logic, making the comparator utilize the noise canceler and edge
select features of the Timer/Counter1 Fault Protection interrupt. When written logic zero, no con-
nection between the Analog Comparator and the Fault Protection function exists. To make the
comparator trigger the Timer/Counter1 Fault Protection interrupt, the FPIE1 bit in the
Timer/Counter1 Control Register D (TCCR1D) must be set.
• Bit 2 – FPF1: Fault Protection Interrupt Flag
When the FPIE1 bit is set (one), the Fault Protection Interrupt is enabled. Activity on the pin will
cause an interrupt request even, if the Fault Protection pin is configured as an output. The corre-
sponding interrupt of Fault Protection Interrupt Request is executed from the Fault Protection
Interrupt Vector. The bit FPF1 is cleared by hardware when executing the corresponding inter-
rupt handling vector. Alternatively, FPF1 is cleared after a synchronization clock cycle by writing
a logical one to the flag. When the SREG I-bit, FPIE1 and FPF1 are set, the Fault Interrupt is
executed.
• Bits 1:0 – WGM1[1:0]: Waveform Generation Mode Bits
These bits together with the PWM1A/PWM1B bits control the counting sequence of the counter
and the type of waveform generation to be used, as shown in Table 12-21. Modes of operation
supported by the Timer/Counter1 are: Normal mode (counter), Fast PWM Mode, Phase and Fre-
quency Correct PWM and PWM6 Modes.
12.12.5 TCCR1E – Timer/Counter1 Control Register E
• Bits 7:6 – Res: Reserved Bits
These bits are reserved and always read zero.
• Bits 5:0 – OC1OE[5:0]: Output Compare Override Enable Bits
These bits are the Ouput Compare Override Enable bits that are used to connect or disconnect
the Output Compare Pins in PWM6 Modes with an instant response on the corresponding Out-
put Compare Pins. The actual value from the port register will be visible on the port pin, when
Table 12-21. Waveform Generation Mode Bit Description
PWM1A/
PWM1B WGM1[1:0]
Timer/Counter
Mode of Operation TOP
Update
OCR1x at
Set TOV1
Flag at
0 XX Normal OCR1C Immediate TOP
1 00 Fast PWM OCR1C TOP TOP
1 01 Phase & Frequency Correct PWM OCR1C BOTTOM BOTTOM
1 10 PWM6 / Single-slope OCR1C TOP TOP
1 11 PWM6 / Dual-slope OCR1C BOTTOM BOTTOM
Bit 76543210
0x00 (0x20) - - OC1OE5 OC1OE4 OC1OE3 OC1OE2 OC1OE1 OC1OE0 TCCR1E
Read/Write R R R/W R/W R/W R/W R/W R/W
Initial value00000000