M34512M2 Datasheet, PDF (20/80 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

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MITSUBISHI MICROCOMPUTERS
4512 Group
SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER
TIMERS
The 4512 Group has the following timers.
• Programmable timer
The programmable timer has a reload register and enables the
frequency dividing ratio to be set. It is decremented from a set-
ting value n. When it underflows (count to n + 1), a timer interrupt
request flag is set to “1,” new data is loaded from the reload reg-
ister, and count continues (auto-reload function).
• Fixed dividing frequency timer
The fixed dividing frequency timer has the fixed frequency divid-
ing ratio (n). An interrupt request flag is set to “1” after every n
count of a count pulse.
FF16
n : Counter initial value
Count starts
Reload
n
1st underflow
Reload
2nd underflow
0016
Timer interrupt ^{“1”}
request flag ^{“0”}
n+1 count
Fig. 18 Auto-reload function
n+1 count
Time
An interrupt occurs or
a skip instruction is executed.
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