Stopwatch Timer (Swt); Outline Of The Stopwatch Timer - Epson S1C17704 Technical Manual

16 Stopwatch Timer (SWT)

16.1 Outline of the Stopwatch Timer

The S1C17704 incorporates a stopwatch timer that counts 1/100 and 1/10 seconds. The stopwatch timer consists of
two 4-bit BCD counters (for 1/100 and 1/10 seconds) that operate with a divided OSC1 clock (256 Hz signal). The
counter data can be read with software.
Furthermore, the stopwatch timer can generate an interrupt using the 100 Hz (approximate 100 Hz), 10 Hz
(approximate 10 Hz), and 1 Hz signals.
Figure 16.1.1 shows the structure of the stopwatch timer.
OSC
OSC1
256 Hz
oscillator/divider
Run/Stop control
To ITC
S1C17704 TECHNICAL MANUAL
Count
SWTRST
Reset
control circuit
SWTRUN
SIE100
Interrupt
SIE10
enable
Interrupt
SIE1
control circuit
Interrupt request
Figure 16.1.1 Structure of Stopwatch Timer
EPSON
16 STOPWATCH TIMER (SWT)
Feedback 1/100 s 4-bit
divider BCD counter
Approx. 100 Hz
Approx. 10 Hz
1 Hz
Stopwatch timer
1/10 s 4-bit
BCD counter
16-1