R01UH0822EJ0100 Rev.1.00
Page 432 of 1041
Jul 31, 2019
RX13T Group
19. Multi-Function Timer Pulse Unit 3 (MTU3c)
(g) PWM Period Setting
In complementary PWM mode, the PWM period is set in two registers—MTU3.TGRA, in which the MTU3.TCNT
upper limit value is set, and TCDRA, in which the MTU4.TCNT upper limit value is set. The settings should be made so
as to achieve the following relationship between these two registers:
With dead time: MTU3.TGRA setting = TCDRA s TDDRA setting
Without dead time: MTU3.TGRA setting = TCDRA s 1
In addition, the settings should be made so as to achieve the following relationship between the TCDRA register and the
TDDRA register:
TCDRA setting > TDDRA setting × 2 + 2
The MTU3.TGRA and TCDRA settings are made by setting values in buffer registers MTU3.TGRC and TCBRA. When
data is written to MTU4.TGRD to enable transfers, the values set in MTU3.TGRC and TCBRA are transferred
simultaneously to the MTU3.TGRA and TCDRA with the transfer timing selected with the MTU3.TMDR1.MD[3:0]
bits.
The new PWM period is reflected from the next cycle when data is updated at the crest, or from the current cycle when
updated in the trough.
illustrates the operation when the PWM period is updated at the crest.
Refer to the following section,
, for the method of updating the data in each buffer register.
Figure 19.49
Example of PWM Period Updating (MTU3 and MTU4)
Counter value
MTU3.TGRC
update
MTU3.TGRA
update
MTU3.TGRA
MTU3.TCNT
MTU4.TCNT
Time
MTU3.TCNT
MTU4.TCNT
TCNTSA