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Section 10 8-Bit Timers
Rev. 4.00 Jan 26, 2006 page 420 of 938
REJ09B0276-0400
16-Bit Count Mode
Channels 0 and 1:
When bits CKS2 to CKS0 are set to B'100 in TCR0, the timer functions as a single 16-bit timer
with channel 0 occupying the upper 8 bits and channel 1 occupying the lower 8 bits.
Setting when Compare Match Occurs
The CMF flag is set to 1 in TCR0 when a 16-bit compare match occurs.
The CMF flag is set to 1 in TCR1 when a lower 8-bit compare match occurs.
TMO
0 pin output control by bits OIS3, OIS2, OS1, and OS0 in TCSR0 is in accordance
with the 16-bit compare match conditions.
TMIO
1 pin output control by bits OIS3, OIS2, OS1, and OS0 in TCSR1 is in
accordance with the lower 8-bit compare match conditions.
Setting when Input Capture Occurs
The CMFB flag is set to 1 in TCR0 and TCR1 when the ICE bit is 1 in TCSR1 and
input capture occurs.
TMIO
1 pin input capture input signal edge detection is selected by bits OIS3 and OIS2
in TCSR0.
Counter Clear Specification
If counter clear on compare match or input capture has been selected by the CCLR1 and
CCLR0 bits in TCR0, the 16-bit counter (both TCNT0 and TCNT1) is cleared.
The settings of the CCLR1 and CCLR0 bits in TCR1 are ignored. The lower 8 bits
cannot be cleared independently.
OVF Flag Operation
The OVF flag is set to 1 in TCSR0 when the 16-bit counter (TCNT0 and TCNT1)
overflows (from H'FFFF to H'0000).
The OVF flag is set to 1 in TCSR1 when the 8-bit counter (TCNT1) overflows (from
H'FF to H'00).
Channels 2 and 3:
When bits CKS2 to CKS0 are set to B'100 in TCR2, the timer functions as a single 16-bit timer
with channel 2 occupying the upper 8 bits and channel 3 occupying the lower 8 bits.
Setting when Compare Match Occurs
The CMF flag is set to 1 in TCR2 when a 16-bit compare match occurs.
The CMF flag is set to 1 in TCR3 when a lower 8-bit compare match occurs.
TMO
2 pin output control by bits OIS3, OIS2, OS1, and OS0 in TCSR2 is in accordance
with the 16-bit compare match conditions.
TMIO
3 pin output control by bits OIS3, OIS2, OS1, and OS0 in TCSR3 is in
accordance with the lower 8-bit compare match conditions.