Specifications

I-60 EPSON S1C62N82 TECHNICAL HARDWARE

CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Stopwatch Timer)

The 10 Hz (approximate 10 Hz) and 1 Hz interrupts can be

generated by the overflow of the SWL and SWH stopwatch

timers, respectively. Also, software can separately mask the

frequencies as described earlier.

Figure 4.8.3 is the timing chart for the stopwatch timer.

Interrupt function

Address

Stopwatch timer (SWL) timing chart

Stopwatch timer (SWH) timing chart

Occurrence of

10 Hz interrupt request

Occurrence of

1 Hz interrupt request

0E3H

(1/10 sec BCD)

0E2H

(1/100 sec BCD)

Fig. 4.8.3

Timing chart for

stopwatch timer

As shown in Figure 4.8.3, the interrupts are generated by

the overflow of the respective timers (9 changing to 0). Also

when this happens, the corresponding interrupt factor flags

(ISW0, ISW1) are set to 1. The respective interrupts can be

masked separately with the interrupt mask registers

(EISW0, EISW1). However, regardless of the setting of the

interrupt mask registers, the interrupt factor flags are set to

1 by the overflow of the corresponding timers.

Reading of interrupt factor flags is available at EI, but be careful in

the following cases. If the interrupt mask register value corre-

sponding to the interrupt factor flags to be read is set to 1, an

interrupt request will be generated by the interrupt factor flags set

timing, or an interrupt request will not be generated.

Be very careful when interrupt factor flags are in the same address.

Note