ATEMGA128-16AI View Datasheet(PDF) - Atmel Corporation
Part Name
Description
MFG CO.
'ATEMGA128-16AI' PDF : 395 Pages View PDF
Timer/Counter1 Control
Register C – TCCR1C
Timer/Counter3 Control
Register C – TCCR3C
ATmega128
Table 62. Clock Select Bit Description
CSn2 CSn1 CSn0 Description
0
0
0
No clock source. (Timer/Counter stopped)
0
0
1
clkI/O/1 (No prescaling
0
1
0
clkI/O/8 (From prescaler)
0
1
1
clkI/O/64 (From prescaler)
1
0
0
clkI/O/256 (From prescaler)
1
0
1
clkI/O/1024 (From prescaler)
1
1
0
External clock source on Tn pin. Clock on falling edge
1
1
1
External clock source on Tn pin. Clock on rising edge
If external pin modes are used for the Timer/Countern, transitions on the Tn pin will
clock the counter even if the pin is configured as an output. This feature allows software
control of the counting.
Bit
7
6
5
4
3
2
1
0
FOC1A FOC1B FOC1C
–
–
–
–
–
TCCR1C
Read/Write
W
W
W
R
R
R
R
R
Initial Value
0
0
0
0
0
0
0
0
Bit
7
6
5
4
3
2
1
0
FOC3A FOC3B FOC3C
–
–
–
–
–
TCCR3C
Read/Write
W
W
W
R
R
R
R
R
Initial Value
0
0
0
0
0
0
0
0
• Bit 7 – FOCnA: Force Output Compare for Channel A
• Bit 6 – FOCnB: Force Output Compare for Channel B
• Bit 5 – FOCnC: Force Output Compare for Channel C
The FOCnA/FOCnB/FOCnC bits are only active when the WGMn3:0 bits specifies a
non-PWM mode. When writing a logical one to the FOCnA/FOCnB/FOCnC bit, an
immediate compare match is forced on the waveform generation unit. The
OCnA/OCnB/OCnC output is changed according to its COMnx1:0 bits setting. Note that
the FOCnA/FOCnB/FOCnC bits are implemented as strobes. Therefore it is the value
present in the COMnx1:0 bits that determine the effect of the forced compare.
A FOCnA/FOCnB/FOCnC strobe will not generate any interrupt nor will it clear the timer
in Clear Timer on Compare Match (CTC) mode using OCRnA as TOP.
The FOCnA/FOCnB/FOCnB bits are always read as zero.
• Bit 4:0 – Reserved Bits
These bits are reserved for future use. For ensuring compatibility with future devices,
these bits must be written to zero when TCCRnC is written.
2467O–AVR–10/06
137
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