atmega32u4-16mu ATMEL Corporation, atmega32u4-16mu Datasheet - Page 133

• Manufacturer Part Number: atmega32u4-16mu
• Description: Atmega32u4 8-bit Avr Microcontroller With 32k Bytes Of Isp Flash And Usb Controller
• Manufacturer: ATMEL Corporation

14.10.5
14.10.6
7766A–AVR–03/08
Timer/Counter1 Control Register C – TCCR1C
Timer/Counter3 Control Register C – TCCR3C
Table 14-5.
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.
•
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 imple-
mented 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.
•
These bits are reserved for future use. For ensuring compatibility with future devices, these bits
must be written to zero when TCCRnC is written.
Bit
Read/Write
Initial Value
Bit
Read/Write
Initial Value
CSn2
Bit 7 – FOCnA: Force Output Compare for Channel A
Bit 4:0 – Reserved Bits
0
0
0
0
1
1
1
1
CSn1
0
0
1
1
0
0
1
1
7
FOC1A
W
0
7
FOC3A
W
0
Clock Select Bit Description
CSn0
6
FOC1B
W
0
6
–
R
0
0
1
0
1
0
1
0
1
Description
No clock source. (Timer/Counter stopped)
clk
clk
clk
clk
clk
External clock source on Tn pin. Clock on falling edge
External clock source on Tn pin. Clock on rising edge
5
FOC1C
W
0
5
–
R
0
I/O
I/O
I/O
I/O
I/O
/1 (No prescaling
/8 (From prescaler)
/64 (From prescaler)
/256 (From prescaler)
/1024 (From prescaler)
4
–
R
0
4
–
R
0
3
–
R
0
3
–
R
0
2
–
R
0
2
–
R
0
1
–
R
0
1
–
R
0
ATmega32U4
0
–
R
0
0
–
R
0
TCCR1C
TCCR3C
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