NEC PD78P214 Manuale Utente
139
Chapter 7 Timer/Counter Units
7
7.2 8-BIT TIMER/COUNTER 1
7.2.1 Functions
Eight-bit timer/counter 1 can function as an interval timer and can also be used for pulse width measurement. In
addition to these basic functions, 8-bit timer/counter 1 can be used as a timer for generating an output trigger on
a real-time output port.
addition to these basic functions, 8-bit timer/counter 1 can be used as a timer for generating an output trigger on
a real-time output port.
(1) Interval timer
When operating as an interval timer, 8-bit timer/counter 1 generates an internal interrupt at specified intervals.
Table 7-9 Intervals of 8-Bit Timer/Counter 1
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.
(2) Pulse width measurement
Eight-bit timer/counter 1 measures the pulse width of a signal applied to the external interrupt request input
pin INTP0.
pin INTP0.
Table 7-10 Pulse Width Measurement Range of 8-Bit Timer/Counter 1
Measurable pulse width
≤2
8
× 16/f
CLK
(683
µ
s)
≤2
8
× 32/f
CLK
(1.37 ms)
≤2
8
× 64/f
CLK
(2.73
µ
s)
≤2
8
× 128/f
CLK
(5.46 ms)
≤2
8
× 256/f
CLK
(10.9 ms)
≤2
8
× 512/f
CLK
(21.8 ms)
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)
The values in parentheses are based on f
CLK
= 6 MHz.