R01UH0823EJ0100 Rev.1.00
Page 745 of 1823
Jul 31, 2019
RX23W Group
26. 8-Bit Timer (TMR)
26.5
Operation with Cascaded Connection
If the CSS[1:0] bits in either TMR0.TCCR or TMR1.TCCR are set to 11b, the TMR 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 TMR0 could be
counted by TMR1 (compare match count mode).
This section describes unit 0. When the two units are cascade-connected, the operation of unit 1 differs in some respects
from that of unit 0.
26.5.1
16-Bit Count Mode
When the TMR0.TCCR.CSS[1:0] bits are set to 11b, the timer functions as a single 16-bit timer with TMR0 occupying
the upper 8 bits and TMR1 occupying the lower 8 bits.
(1) Counter Clear Specification
The settings of the TMR0.TCR.CCLR[1:0] bits become effective for the 16-bit counter. If the
TMR0.TCR.CCLR[1:0] bits have been set for counter clear at compare match, the 16-bit counter (TMR0.TCNT
and TMR1.TCNT together) is cleared when a 16-bit compare match event occurs. The counter of unit 1 can also be
cleared by the signal on the TMRI2 pin (an external signal to reset the counter).
The settings of the TMR1.TCR.CCLR[1:0] bits are ignored.
(2) Pin Output
Control of output from the TMO0 pin by the TMR0.TCSR.OSA[1:0] and OSB[1:0] bits is in accordance with the
16-bit compare match conditions.
Control of output from the TMO1 pin by the TMR1.TCSR.OSA[1:0] and OSB[1:0] bits is in accordance with the
lower 8-bit compare match conditions. Output from TMR3 in unit 1 is not available since the chip does not have a
pin equivalent to the TMO1 pin for TMR1 of unit 0.
26.5.2
Compare Match Count Mode
When the TMR1.TCCR.CSS[1:0] bits are set to 11b, TMR1.TCNT counts the number of occurrences of compare match
A for TMR0. TMR0 and TMR1 are controlled independently. Conditions such as generation of interrupts, output from
the TMOn pin (n = 0, 1), and counter clear are in accordance with the settings for each channel. Output from TMR3 in
unit 1 is not available since the chip does not have a pin equivalent to the TMO1 pin for TMR1 of unit 0.