Panasonic MN101C77C User Manual

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Chapter 7    16-bit Timer

16-bit High Precision PWM Output

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High Precision PWM Output Setup Example (Timer 7)

The TM7IO output pin outputs the 1/4 duty PWM output waveform at 400 Hz with timer 7. Select fosc/2
(at fosc = 20 MHz) as a clock source. One cycle of the PWM output waveform is decided by the set value
of a compare register 1. "H" period of the PWM output waveform is decided by the set value of a
compare register 2.
An example setup procedure, with a description of each step is shown below.

(1) Set the TM7EN flag of the timer 7 mode

register 1 (TM7MD1) to "0" to stop timer 7
counting.

(2) Set the P1OMD4 flag of the port 1 output mode

register (P1OMD) to "1" to set the P14 pin as a
special function pin. Set the P1DIR4 flag of the
port 1 direction control register (P1DIR) to "1"
for output mode.
Add pull-up resistor, if it necessary.

(3) Set the TM7PWM flag of the timer 7 mode

register 2 (TM7MD2) to "1" to select the PWM
output.

(4) Set the TM7BCR flag of the TM7MD2 register

to "1" to select the TM7OC1 compare match
as a clear source of binary counter.
Also, set the T7PWMSL flag to "1" to select the
TM7OC2 compare match as a duty decision
source of the PWM output.

Setup Procedure

(1) Stop the counter.

TM7MD1 (x'3F78')

bp4

: TM7EN

= 0

(2) Set the special function pin to output

mode.

P1OMD (x'3F2F')

bp4

:P1OMD4

= 1

P4DIR (x'3F31')

bp4

: P1DIR4

= 1

(3) Set the PWM output.

TM7MD2 (x'3F79')

bp4

: TM7PWM = 1

(4) Set the high precision PWM output

operation.

TM7MD2 (x'3F79')

bp5

: TM7BCR = 1

bp6

: T7PWMSL = 1

Description

TM7IO output

400 Hz

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