SIC63616-(Rev. 1.0) NO. P80
3240-0412
4.7.4 Interrupt function
The clock timer can generate an interrupt at the falling edge of 128 Hz, 64 Hz, 32 Hz, 16 Hz, 8 Hz, 4 Hz, 2
Hz and 1 Hz signals. Software can enable or mask any of these frequencies to generate interrupts.
Figure 4.7.4.1 is the timing chart of the clock timer.
Address
FF41H
FF42H
128 Hz interrupt request
64 Hz interrupt request
32 Hz interrupt request
16 Hz interrupt request
8 Hz interrupt request
4 Hz interrupt request
2 Hz interrupt request
1 Hz interrupt request
Bit
D0
D1
D2
D3
D0
D1
D2
D3
Frequency
Clock timer timing chart
128 Hz
64 Hz
32 Hz
16 Hz
8 Hz
4 Hz
2 Hz
1 Hz
Fig. 4.7.4.1 Timing chart of clock timer
As shown in Figure 4.7.4.1, an interrupt is generated at the falling edge of each frequency signal (128 Hz, 64
Hz, 32 Hz, 16 Hz, 8 Hz, 4 Hz, 2 Hz, 1 Hz). At this time, the corresponding interrupt factor flag (IT0, IT1, IT2,
IT3, IT4, IT5, IT6, IT7) is set to "1". The interrupt mask registers (EIT0, EIT1, EIT2, EIT3, EIT4, EIT5, EIT6,
EIT7) are used to enable or mask each interrupt factor. However, regardless of the interrupt mask register
setting, the interrupt factor flag is set to "1" at the falling edge of the corresponding signal.