D12320VF25V Datasheet, PDF (439/1146 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 10 8-Bit Timers
10.3.5 Operation with Cascaded Connection
If bits CKS2 to CKS0 in either TCR0 or TCR1 are set to B'100, the 8-bit timers of the two
channels are cascaded. With this configuration, a single 16-bit timer could be used (16-bit counter
mode) or compare matches of the 8-bit channel 0 could be counted by the timer of channel 1
(compare match counter mode). In this case, the timer operates as below.
16-Bit Counter Mode: When bits CKS2 to CKS0 in TCR0 are set to B'100, 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 of compare match flags
⎯ The CMF flag in TCSR0 is set to 1 when a 16-bit compare match event occurs.
⎯ The CMF flag in TCSR1 is set to 1 when a lower 8-bit compare match event occurs.
• Counter clear specification
⎯ If the CCLR1 and CCLR0 bits in TCR0 have been set for counter clear at compare match,
the 16-bit counter (TCNT0 and TCNT1 together) is cleared when a 16-bit compare match
event occurs. The 16-bit counter (TCNT0 and TCNT1 together) is cleared even if counter
clear by the TMRI0 pin has also been set.
⎯ The settings of the CCLR1 and CCLR0 bits in TCR1 are ignored. The lower 8 bits cannot
be cleared independently.
• Pin output
⎯ Control of output from the TMO0 pin by bits OS3 to OS0 in TCSR0 is in accordance with
the 16-bit compare match conditions.
⎯ Control of output from the TMO1 pin by bits OS3 to OS0 in TCSR1 is in accordance with
the lower 8-bit compare match conditions.
Compare Match Counter Mode: When bits CKS2 to CKS0 in TCR1 are B'100, TCNT1 counts
compare match A’s for channel 0.
Channels 0 and 1 are controlled independently. Conditions such as setting of the CMF flag,
generation of interrupts, output from the TMO pin, and counter clear are in accordance with the
settings for each channel.
Usage Note: If the 16-bit counter mode and compare match counter mode are set simultaneously,
the input clock pulses for TCNT0 and TCNT1 are not generated and thus the counters will stop
operating. Software should therefore avoid using both these modes.
Rev.7.00 Feb. 14, 2007 page 405 of 1108
REJ09B0089-0700