Renesas RX100 Series User Manual page 433

RX13T Group
(h) Register Data Updating
The buffer registers are used to update the data in five compare registers for the PWM duty and PWM period in
complementary PWM mode. The update data can be written to the buffer register at any time.
There is a temporary register between each of these registers and its buffer register. While subcounter TCNTSA is not
counting, if buffer register data is updated, the temporary register value also changes. Data is not transferred from buffer
registers to temporary registers while TCNTSA is counting; in this case, the value written to a buffer register is
transferred after TCNTSA halts.
The temporary register value is transferred to the compare register at the data update timing set with
MTU3.TMDR1.MD[3:0] bits. Figure 19.50 shows an example of data updating in complementary PWM mode (MTU3
and MTU4). This example shows the mode in which data is updated at both the counter crest and trough.
When updating buffer register data, be sure to write to MTU4.TGRD at the end of the update. Data is transferred from
buffer registers to the temporary registers simultaneously for all five registers after the write to MTU4.TGRD.
Even when not updating all five registers or when not updating the MTU4.TGRD data, be sure to write to MTU4.TGRD
after writing data to the registers to be updated. In this case, the data written to MTU4.TGRD should be the same as the
data prior to the write operation.
Refer to section 19.3.8 (2) (r), Double Buffer Function in Complementary PWM Mode , for data updating when
the double buffer function is used.
R01UH0822EJ0100 Rev.1.00
Jul 31, 2019
19. Multi-Function Timer Pulse Unit 3 (MTU3c)
Page 433 of 1041