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R01UH0823EJ0110 Rev.1.10 Page 580 of 1852
Nov 30, 2020
RX23W Group 23. Multi-Function Timer Pulse Unit 2 (MTU2a)
(p) Example of Waveform Output for Driving AC Synchronous Motor (Brushless DC Motor)
In complementary PWM mode, a brushless DC motor can easily be controlled using the TGCR register. Figure 23.63 to
Figure 23.66 show examples of brushless DC motor driving waveforms created using the TGCR register.
To switch the output phases for a 3-phase brushless DC motor by means of external signals detected with a Hall element,
etc., set the TGCR.FB bit to 0. In this case, the external signals indicating the magnetic pole position should be input to
timer input pins MTIOC0A, MTIOC0B, and MTIOC0C in MTU0. When an edge is detected at pin MTIOC0A,
MTIOC0B, or MTIOC0C, the output on/off state is switched automatically.
When the TGCR.FB bit is 1, the output on/off state is switched when the TGCR.UF bit, TGCR.VF bit, or TGCR.WF bit
is set to 0 or 1.
The driving waveforms are output from the 6-phase PWM output pins for complementary PWM mode.
With this 6-phase output, while the output is turned on, chopping output is available through complementary PWM mode
output function by setting the TGCR.N bit or TGCR.P bit to 1. When the TGCR.N bit or TGCR.P bit is 0, the level
output is selected.
The active level of the 6-phase output (on output level) can be set with the TOCR1.OLSN bit and TOCR1.OLSP bit
regardless of the setting of the TGCR.N bit and TGCR.P bit.
Figure 23.63 Example of Output Phase Switching by External Input (1)
MTIOC0A pin
MTIOC0B pin
MTIOC0C pin
MTIOC3B pin
MTIOC3D pin
MTIOC4A pin
MTIOC4C pin
MTIOC4B pin
MTIOC4D pin
6-phase output
External input
When TGCR.BDC = 1, TGCR.N = 0, TGCR.P = 0, and TGCR.FB = 0,
the high level is the active level for output.