Stopwatch Timer - Epson S1C63616 Technical Manual

4.8 Stopwatch Timer

4.8.1 Configuration of stopwatch timer
The S1C63616 has a 1/1,000 sec stopwatch timer. The stopwatch timer is configured of a 3-stage, 4-bit BCD
counter serving as the input clock of a 1,000 Hz signal output from the prescaler. Data can be read out four
bits (1/1,000 sec, 1/100 sec and 1/10 sec) at a time by the software.
In addition it has a direct input function that controls the stopwatch timer RUN/STOP and LAP using the
input ports P10 and P11.
Figure 4.8.1.1 is the block diagram of the stopwatch timer.
[SWCKE]
OSC1
f
OSC1
oscillation
Clock
circuit manager
(f )
OSC1
[SWDIR]
P11
Direct
input
P10 control
P12, P13,
[DKM2–0]
P40–P43
[LCURF]
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.
4.8.2 Controlling clock manager
The clock manager generates the stopwatch timer operating clock by dividing the OSC1 clock by 32.
Before the stopwatch timer can be run, write "1" to the SWCKE register to supply the operating clock to the
stopwatch timer.
If it is not necessary to run the stopwatch timer, stop the clock supply by setting SWCKE to "0" to reduce
current consumption.
[SWRST]
/ (1,000 Hz)
32
1,000 / 1,024 1/1,000 sec
prescaler counter
Capture
control
circuit
[SWRUN]
[EDIR]
[CRNWF]
Fig. 4.8.1.1 Block diagram of stopwatch timer
Table 4.8.2.1 Controlling stopwatch timer operating clock
SWCKE
1
0
1/100 sec 1/10 sec
counter counter
Capture buffer
SWD0–3 SWD4–7
reading reading
Data bus
Stopwatch timer clock
f / 32 (1 kHz)
OSC1
Off
SIC63616-(Rev. 1.0) NO. P84
1 Hz interrupt request
10 Hz interrupt request
SWD8–11
reading
Direct RUN interrupt request
Direct LAP interrupt request
3240-0412