M16CSLASH26 datasheet(106/239 Pages) RENESAS

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Renesas Technology Corp.

Three-Phase Motor Control Timer Function

100

M16C/26 Group

SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

Under

development

Preliminary Specifications Rev. 0.9

Specifications in this manual are tentative and subject to change.

Figure 1.14.7 shows the block diagram for three-phase PWM output mode. When selecting output polar-

ity “L” active in three-phase PWM output 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 time timer (034C16), 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 at 034916). 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 PWM output mode are output from respective ports by means of

setting “1” in the output control bit (bit 3 at 034816). 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 (bit 4 at 034816) 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 port becomes the state of set by port direction register.

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