Epson S1C63558, Техническое руководство

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S1C63558 TECHNICAL MANUAL
EPSON
61
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Stopwatch Timer)
4.9 Stopwatch Timer
4.9.1 Configuration of stopwatch timer
The S1C63558 has 1/100 sec unit and 1/10 sec unit stopwatch timer built-in. The stopwatch timer is
configured with a 2 levels 4-bit BCD counter which has an input clock approximating 100 Hz signal
(signal divided from OSC1 to the closest 100 Hz) and data can be read in units of 4 bits by software.
Figure 4.9.1.1 shows the configuration of the stopwatch timer.
SWD0–3
Data bus
10 Hz, 1 Hz
256 Hz 10 Hz
Stopwatch timer reset signal
Divider
Interrupt
request
Interrupt
control
SWD4–7
Stopwatch timer RUN/STOP signal
Stopwatch timer
OSC1
oscillation circuit
(f
OSC1
)
Fig. 4.9.1.1 Configuration of stopwatch timer
The stopwatch timer can be used as a separate timer from the clock timer. In particular, digital watch
stopwatch functions can be realized easily with software.
4.9.2 Count-up pattern
The stopwatch timer is configured of 4-bit BCD counters SWD0–SWD3 and SWD4–SWD7.
The counter SWD0–SWD3, at the stage preceding the stopwatch timer, has an approximated 100 Hz
signal for the input clock. It counts up every 1/100 sec, and generates an approximated 10 Hz signal. The
counter SWD4–SWD7 has an approximated 10 Hz signal generated by the counter SWD0–SWD3 for the
input clock. In count-up every 1/10 sec, and generated 1 Hz signal.
Figure 4.9.2.1 shows the count-up pattern of the stopwatch timer.
26
256 26
256 26
256 26
256 26
256 26
256 25
256 25
256 25
256 25
256
3
256 2
256 3
256 2
256 2
256 2
256 3
256 3
256 3
256 2
256
3
256 2
256 3
256 3
256 3
256 3
256 3
256 2
256 2
256 2
256
26
256
25
256
26
256 25
256
x 6 +
x 4 = 1 (sec)
0 1 2 3 4 5 6 7 8 9 0
0 1 2 3 4 5 6 7 8 9 0
0 1 2 3 4 5 6 7 8 9 0
1 Hz
signal
generation
Approximate
10 Hz
signal
generation
Approximate
10 Hz
signal
generation
SWD4–7 count value
Counting time (sec)
(sec)
(sec)
SWD0–3 count value
Counting time (sec)
SWD0–3 count value
Counting time (sec)
SWD4–7 count-up pattern
SWD0–3 count-up pattern 1
SWD0–3 count-up pattern 2
Fig. 4.9.2.1 Count-up pattern of stopwatch timer