HD4074344 Datasheet, PDF (60/100 Pages) Hitachi Semiconductor – 4-bit microcomputers

HD404344R Series/HD404394 Series
Notes on Use
When using the timer output as PWM output, note the following point. From the update of the timer write
register until the occurrence of the overflow interrupt, the PWM output differs from the period and duty
settings, as shown in table 20. The PWM output should therefore not be used until after the overflow
interrupt following the update of the timer write register. After the overflow, the PWM output will have the
set period and duty cycle.
Table 20 PWM Output Following Update of Timer Write Register
PWM Output
Timer Write Register is Updated during High Timer Write Register is Updated during Low
Mode PWM Output
PWM Output
Free
running
Timer write
register
updated to
value N
Interrupt
request
Timer write
register
updated to
value N
Interrupt
request
Reload
T × (255 – N) T × (N + 1)
Timer write
register
updated to
value N
Interrupt
request
T × (N' + 1)
T × (255 – N) T × (N + 1)
Timer write
register
updated to
value N
Interrupt
request
T
T × (255 – N)
T
T
T × (255 – N)
T
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