R01UH0822EJ0100 Rev.1.00
Page 496 of 1041
Jul 31, 2019
RX13T Group
19. Multi-Function Timer Pulse Unit 3 (MTU3c)
19.6.25
Notes to Prevent Malfunctions in Synchronous Clearing for Complementary
PWM Mode
If control of the output waveform is enabled (TWCRA.WRE bit = 1) at the time of synchronous counter clearing in
complementary PWM mode, satisfaction of either condition 1 or 2 below has the following effects.
Dead time on the PWM output pins is shortened (or disappears).
The active level is output on the negative phase PWM output pins beyond the period for active-level output.
Condition 1: In portion (10) of the initial output inhibition period in
, synchronous clearing occurs within
the dead-time period for PWM output.
Condition 2: In portions (10) and (11) of the initial output inhibition period in
, synchronous clearing
occurs when any condition from among MTU3.TGRB ≤ TDDRA, MTU4.TGRA ≤ TDDRA, or
MTU4.TGRB ≤ TDDRA is satisfied.
The following method avoids the above phenomena.
Ensure that synchronous clearing proceeds with the value of each comparison register (MTU3.TGRB, MTU4.TGRA,
and MTU4.TGRB) set to at least double the value of the TDDRA register.
Figure 19.138
Example of Synchronous Clearing (When Condition 1 Applies)
MTU3.TGRA
TGR
TDDR
0
PWM output
(negative phase)
MTU3.
TCNT
MTU4.
TCNT
Tb interval
Tb interval
Synchronous clearing
10
11
TDDRA
Dead time is shortened.
Initial output
inhibition
Note:
PWM output is active low.
: Dead time
10
11
PWM output
(positive phase)