NEC PD750008 - Manual (Page 142)

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µPD750008 USER'S MANUAL
(5) Operation after the modulo register is changed
The contents of the modulo register are changed when an 8-bit data memory manipulation instruction is
executed.
If the new value of the modulo register is less than the value of the count register, the count register
continues count operation until it overflows, then it restarts count operation from 0. Accordingly, if the
new value (m) of the modulo register is less than the value (n) before it is changed, the timer must be
restarted after the contents of the modulo register are changed.
Re-set instruction Re-set instruction
Clock A specified Clock B specified Clock A specified
Clock A
Clock B
CP
<1> <2>
n m
x – 1 x 255 0 1
n > x > m
Modulo register
Count register
CP
Re-set instruction
n m
n 0 1 m 0
Match signal Match signal
Modulo register
Count register
CP