HD404618 Datasheet, PDF (52/91 Pages) Hitachi Semiconductor – 4-Bit Single-Chip Microcomputer

HD404618 Series
Note on Use
When using the timer output as PWM output, note the following point. From the update of the timer write
register untill the occurrence of the overflow interrupt, the PWM output differs from the period and duty
settings, as shown in table 24. 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 24 PWM Output Following Update of Timer Write Register
PWM Output
Mode
Timer Load Register is Updated during
High PWM Output
Free running
Timer load
register
updated to
value N
Interrupt
request
Timer Load Register is Updated during
Low PWM Output
Timer load
register
updated to
value N
Interrupt
request
Reload
T × (255 – N) T × (N + 1)
Timer load
register
updated to
value N
Interrupt
request
T × (N' + 1)
T × (255 – N) T × (N + 1)
Timer load
register
updated to
value N
Interrupt
request
T
T × (255 – N)
T
T
T × (255 – N)
T
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