R01UH0823EJ0100 Rev.1.00
Page 607 of 1823
Jul 31, 2019
RX23W Group
23. Multi-Function Timer Pulse Unit 2 (MTU2a)
23.6.23
Notes When Complementary PWM Mode Output Protection Functions are Not
Used
The complementary PWM mode output protection functions are initially enabled. Refer to
, for details.
23.6.24
Points for Caution to Prevent Malfunctions in Synchronous Clearing for
Complementary PWM Mode
If control of the output waveform is enabled (TWCR.WRE = 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 PWM inverse-phase 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 ≤ TDDR, MTU4.TGRA ≤ TDDR, or MTU4.TGRB
≤ TDDR 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 dead time data register (TDDR).
Figure 23.111
Example of Synchronous Clearing (When Condition 1 Applies)
MTU3.TGRA
TGR
TDDR
0
Negative-phase
output
MTU3.
TCNT
MTU4.
TCNT
Tb interval
Tb interval
Synchronous clearing
10
11
TDDR
Dead time is shortened.
Initial output
inhibition
: Dead time
10
11
Positive-phase
output
Note:
PWM output is active-low.