M16C Datasheet, PDF (103/262 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

Preliminary Specifications REV.B
Specifications in this manual are tentative and subject to change.
Mitsubishi microcomputers
M16C / 6N Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Timers’ functions for three-phase motor control
Figure 11-5 shows the block diagram for three-phase waveform mode. In three-phase waveform mode, the
positive-phase waveforms (U phase, V phase, and W phase) and negative waveforms (U phase, V phase,
and W phase), six waveforms in total, are output from P80, P81, P72, P73, P74, and P75 as active on the
“L” level. Of the timers used in this mode, timer A4 controls the U phase and U phase, timer A1 controls the
V phase and V phase, and timer A2 controls the W phase and W phase respectively; timer B2 controls the
periods of one-shot pulse output from timers A4, A1, and A2.
In outputting a waveform, dead time can be set so as to cause the “L” level of the positive waveform output
(U phase, V phase, and W phase) not to lap over the “L” level of the negative waveform output (U phase,
V phase, and W phase).
To set short circuit time, use three 8-bit timers sharing the reload register for setting dead time. A value
from 1 through 255 can be set as the count of the timer for setting dead time. The timer for setting dead
time works as a one-shot timer. If a value is written to the dead timer (01CC16), the value is written to the
reload register shared by the three timers for setting dead time.
Any of the timers for setting dead time takes the value of the reload register into its counter, if a start
trigger comes from its corresponding timer, and performs a down count in line with the clock source
selected by the dead time timer count source select bit (bit 2) of three-phase PWM control register 1
(01C916). The timer can receive another trigger again before the workings due to the previous trigger are
completed. In this instance, the timer performs a down count from the reload register’s content after its
transfer, provoked by the trigger, to the timer for setting dead time.
Since the timer for setting dead time works as a one-shot timer, it starts outputting pulses if a trigger
comes; it stops outputting pulses as soon as its content becomes 0016, and waits for the next trigger to
come.
The positive waveforms (U phase, V phase, and W phase) and the negative waveforms (U phase, V
phase, and W phase) in three-phase waveform mode are output from respective ports by means of setting
“1” in the output control bit (bit 3) of three-phase PWM control register 0 (01C816). Setting “0” in this bit
causes the ports to be the state of set by port direction register. This bit can be set to “0” not only by use
of the applicable instruction, but by entering a falling edge in the NMI terminal or by resetting. Also, if “1” is
set in the positive and negative phases concurrent L output disable function enable bit (bit4) of three-
phase PWM control register 0 (01C816) causes one of the pairs of U phase and U phase, V phase and V
phase, and W phase and W phase concurrently go to “L”, as a result, the output control bit become the
state of set by port direction register.
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