Interrupt Function - Epson S1C63666 Technical Manual

CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Clock Timer)

4.9.3 Interrupt function

The clock timer can cause interrupts at the falling edge of 32 Hz, 8 Hz, 2 Hz and 1 Hz signals. Software
can set whether to mask any of these frequencies.
Figure 4.9.3.1 is the timing chart of the clock timer.
Address Bit Frequency
D0 128 Hz
D1 64 Hz
FF75H
D2 32 Hz
D3 16 Hz
D0 8 Hz
D1 4 Hz
FF76H
D2 2 Hz
D3 1 Hz
32 Hz interrupt request
8 Hz interrupt request
2 Hz interrupt request
1 Hz interrupt request
As shown in Figure 4.9.3.1, interrupt is generated at the falling edge of the frequencies (32 Hz, 8 Hz, 2 Hz,
1 Hz). At this time, the corresponding interrupt factor flag (IT0, IT1, IT2, IT3) is set to "1". Selection of
whether to mask the separate interrupts can be made with the interrupt mask registers (EIT0, EIT1, EIT2,
EIT3). However, regardless of the interrupt mask register setting, the interrupt factor flag is set to "1" at
the falling edge of the corresponding signal.
64
Clock timer timing chart
Fig. 4.9.3.1 Timing chart of clock timer
EPSON
S1C63666 TECHNICAL MANUAL