NEC PD78212, User Manual

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159
Chapter 7 Timer/Counter Units
7
7.3 8-BIT TIMER/COUNTER 2
7.3.1 Functions
Eight-bit timer/counter 2 has two functions not available with the other three timers/counters:
• External event counter
• One-shot timer
This section describes the following four basic functions in sequence:
• Interval timer
• Programmable square wave output
• Pulse width measurement
• External event counter
(1) Interval timer
When operating as an interval timer, 8-bit timer/counter 2 generates an internal interrupt at specified intervals.
Table 7-11 Intervals of 8-Bit Timer/Counter 2
Resolution
16/f
CLK
(2.6
µ
s)
32/f
CLK
(5.3
µ
s)
64/f
CLK
(10.7
µ
s)
128/f
CLK
(21.3
µ
s)
256/f
CLK
(42.7
µ
s)
512/f
CLK
(85.3
µ
s)
Maximum interval
2
8
×
16/f
CLK
(683
µ
s)
2 8
×
32/f
CLK
(1.37 ms)
2
8
×
64/f
CLK
(2.73 ms)
2
8
×
128/f
CLK
(5.46 ms)
2
8
×
256/f
CLK
(10.9 ms)
2
8
×
512/f
CLK
(21.8 ms)
Minimum interval
16/f
CLK
(2.6
µ
s)
32/f
CLK
(5.3
µ
s)
64/f
CLK
(10.7
µ
s)
128/f
CLK
(21.3
µ
s)
256/f
CLK
(42.7
µ
s)
512/f
CLK
(85.3
µ
s)
The values in parentheses are based on f
CLK
= 6 MHz.