Epson E0C6001, Техническое руководство

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E0C6001 TECHNICAL HARDWARE
I-46
The clock timer can interrupt on the falling edge of the 32
Hz, 8 Hz, and 2 Hz signals. The software can mask any of
these interrupt signals.
Figure 4.7.2 is the timing chart of the clock timer.
Interrupt function
Clock timer timing chart
Frequency
Register
bits
Address
0E4H
D0 16 Hz
D1
D2
D3
8 Hz
4 Hz
2 Hz
Occurrence of
32 Hz interrupt request
Occurrence of
8 Hz interrupt request
Occurrence of
2 Hz interrupt request
As shown in Figure 4.7.2, an interrupt is generated on the
falling edge of the 32 Hz, 8 Hz, and 2 Hz frequencies. When
this happens, the corresponding interrupt event flag (IT32,
IT8, IT2) is set to 1. Masking the separate interrupts can be
done with the interrupt mask register (EIT32, EIT8, EIT2).
However, regardless of the interrupt mask register setting,
the interrupt event flags will be set to 1 on the falling edge of
their corresponding signal (e.g. the falling edge of the 2 Hz
signal sets the 2 Hz interrupt factor flag to 1).
Write to the interrupt mask register (EIT32, EIT8, EIT2) and read
the interrupt factor flags (IT32, IT8, IT2) only in the DI status
(interrupt flag = 0). Otherwise, it causes malfunction.
Note
Fig. 4.7.2 Timing chart of the clock timer