AT90PWM216-16SE ATMEL [ATMEL Corporation], AT90PWM216-16SE Datasheet - Page 100

• Manufacturer Part Number: AT90PWM216-16SE
• Description: 8-bit Microcontroller with 16K Bytes In-System Programmable flash
• Manufacturer: ATMEL [ATMEL Corporation]

14.8.2
100
AT90PWM216/316
Timer/Counter Control Register B – TCCR0B
• 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.
A FOC0B strobe will not generate any interrupt, nor will it clear the timer in CTC mode using
OCR0B as TOP.
The FOC0B bit is always read as zero.
• Bits 5:4 – Res: Reserved Bits
These bits are reserved bits in the AT90PWM216/316 and will always read as zero.
• Bit 3 – WGM02: Waveform Generation Mode
See the description in the
• Bits 2:0 – CS02:0: Clock Select
The three Clock Select bits select the clock source to be used by the Timer/Counter.
Table 14-9.
Bit
Read/Write
Initial Value
CS02
0
0
0
0
CS01
0
0
1
1
Clock Select Bit Description
FOC0A
W
7
0
CS00
0
1
0
1
FOC0B
Description
No clock source (Timer/Counter stopped)
clk
clk
clk
“Timer/Counter Control Register A – TCCR0A” on page
W
6
0
I/O
I/O
I/O
/(No prescaling)
/8 (From prescaler)
/64 (From prescaler)
R
5
0
–
R
4
–
0
WGM02
R
3
0
CS02
R
2
0
CS01
R/W
1
0
CS00
R/W
0
0
7710D–AVR–08/09
97.
TCCR0B