SIC63616-(Rev. 1.0) NO. P84
3240-0412
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.
Clock
manager
[SWCKE]
f
OSC1
/32
OSC1
oscillation
circuit
(f
OSC1
)
Data bus
1 Hz interrupt request
1,000 / 1,024
prescaler
1/1,000 sec
counter
1/100 sec
counter
1/10 sec
counter
Capture buffer
SWD0–3
reading
SWD4–7
reading
SWD8–11
reading
[SWRST]
10 Hz interrupt request
Capture
control
circuit
[SWRUN]
[EDIR]
[CRNWF]
[DKM2–0]
[LCURF]
Direct RUN interrupt request
Direct LAP interrupt request
(1,000 Hz)
Direct
input
control
[SWDIR]
P11
P10
P12, P13,
P40–P43
Fig. 4.8.1.1 Block diagram 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.
4.8.2 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.
Table 4.8.2.1 Controlling stopwatch timer operating clock
SWCKE
1
0
Stopwatch timer clock
f
OSC1
/ 32 (1 kHz)
Off
If it is not necessary to run the stopwatch timer, stop the clock supply by setting SWCKE to "0" to reduce
current consumption.