ATA5771 ATMEL Corporation, ATA5771 Datasheet - Page 134

• Manufacturer Part Number: ATA5771
• Manufacturer: ATMEL Corporation

11.9.2
82
ATtiny24/44/84
TCCR0B – Timer/Counter Control Register B
Table 11-8.
Note:
• Bit 7 – FOC0A: Force Output Compare A
The FOC0A bit is only active when the WGM bits specify a non-PWM mode.
However, for ensuring compatibility with future devices, this bit must be set to zero when
TCCR0B is written when operating in PWM mode. When writing a logical one to the FOC0A bit,
an immediate Compare Match is forced on the Waveform Generation unit. The OC0A output is
changed according to its COM0A1:0 bits setting. Note that the FOC0A bit is implemented as a
strobe. Therefore it is the value present in the COM0A1:0 bits that determines the effect of the
forced compare.
A FOC0A strobe will not generate any interrupt, nor will it clear the timer in CTC mode using
OCR0A as TOP.
The FOC0A bit is always read as zero.
• Bit 6 – FOC0B: Force Output Compare B
The FOC0B bit is only active when the WGM bits specify a non-PWM mode.
However, for ensuring compatibility with future devices, this bit must be set to zero when
TCCR0B is written when operating in PWM mode. When writing a logical one to the FOC0B bit,
an immediate Compare Match is forced on the Waveform Generation unit. The OC0B output is
changed according to its COM0B1:0 bits setting. Note that the FOC0B bit is implemented as a
strobe. Therefore it is the value present in the COM0B1:0 bits that determines the effect of the
forced compare.
Bit
0x33 (0x53)
Read/Write
Initial Value
Mode
0
1
2
3
4
5
6
7
1. MAX
BOTTOM = 0x00
WGM02
Waveform Generation Mode Bit Description
0
0
0
0
1
1
1
1
FOC0A
W
7
0
= 0xFF
WGM01
FOC0B
0
0
1
1
0
0
1
1
W
6
0
WGM00
0
1
0
1
0
1
0
1
R
5
0
–
Timer/Counter
Mode of Operation
Normal
PWM, Phase
Correct
CTC
Fast PWM
Reserved
PWM, Phase
Correct
Reserved
Fast PWM
R
4
–
0
WGM02
R/W
3
0
CS02
R/W
2
0
OCRA
OCRA
OCRA
0xFF
0xFF
0xFF
TOP
–
–
CS01
R/W
1
0
Update of
Immediate
Immediate
BOTTOM
BOTTOM
OCRx at
TOP
TOP
–
–
CS00
R/W
0
0
8006G–AVR–01/08
TOV Flag
BOTTOM
BOTTOM
Set on
MAX
MAX
MAX
TOP
TCCR0B
–
–
(1)