RL78/G15 CHAPTER 6 TIMER ARRAY UNIT
R01UH0959EJ0110 Rev.1.10 Page 279 of 765
Mar 7, 2023
6.9.3 Operation as multiple PWM output function
By extending the PWM function and using multiple slave channels, many PWM waveforms with different duty values can
be output.
For example, when using two slave channels, the period and duty factor of an output pulse can be calculated by the
following expressions.
Pulse period = {Set value of TDRmn (master) + 1} × Count clock period
Duty factor 1[%] = {Set value of TDRmp (slave 1)}/{Set value of TDRmn (master) + 1} × 100
Duty factor 2[%] = {Set value of TDRmq (slave 2)}/{Set value of TDRmn (master) + 1} × 100
Remark Although the duty factor exceeds 100% if the set value of TDRmp (slave 1) > {set value of TDRmn (master) +
1} or if the {set value of TDRmq (slave 2)} > {set value of TDRmn (master) + 1}, it is summarized into 100%
output.
Timer count register mn (TCRmn) of the master channel operates in the interval timer mode and counts the periods.
The TCRmp register of the slave channel 1 operates in one-count mode, counts the duty factor, and outputs a PWM
waveform from the TOmp pin. The TCRmp register loads the value of timer data register mp (TDRmp), using INTTMmn
of the master channel as a start trigger, and starts counting down. When TCRmp = 0000H, TCRmp outputs INTTMmp
and stops counting until the next start trigger (INTTMmn of the master channel) has been input. The output level of
TOmp becomes active one count clock after generation of INTTMmn from the master channel, and inactive when
TCRmp = 0000H.
In the same way as the TCRmp register of the slave channel 1, the TCRmq register of the slave channel 2 operates in
one-count mode, counts the duty factor, and outputs a PWM waveform from the TOmq pin. The TCRmq register loads
the value of the TDRmq register, using INTTMmn of the master channel as a start trigger, and starts counting down.
When TCRmq = 0000H, the TCRmq register outputs INTTMmq and stops counting until the next start trigger (INTTMmn
of the master channel) has been input. The output level of TOmq becomes active one count clock after generation of
INTTMmn from the master channel, and inactive when TCRmq = 0000H.
When channel 0 is used as the master channel as above, up to seven types of PWM signals can be output at the same
time.
Caution To rewrite both timer data register mn (TDRmn) of the master channel and the TDRmp register of the
slave channel 1, write access is necessary at least twice. Since the values of the TDRmn and TDRmp
registers are loaded to the TCRmn and TCRmp registers after INTTMmn is generated from the master
channel, if rewriting is performed separately before and after generation of INTTMmn from the master
channel, the TOmp pin cannot output the expected waveform. To rewrite both the TDRmn register of
the master and the TDRmp register of the slave, be sure to rewrite both the registers immediately
after INTTMmn is generated from the master channel (This applies also to the TDRmq register of the
slave channel 2).
Remark m: Unit number (m = 0), n: Master channel number (n = 0, 2, 4)
p: Slave channel number, q: Slave channel number
n < p < q ≤ 7 (Where p and q are integers greater than n)
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