Clock Timer; Configuration Of Clock Timer; Interrupt Function - Epson S1C60N03 Technical Manual

4.6 Clock Timer

4.6.1 Configuration of clock timer

The S1C60N03 Series has a built-in clock timer that uses the oscillation circuit as the clock source. The
clock timer is configured as a 7-bit binary counter that counts with a 256 Hz source clock from the
divider. The high-order 4 bits of the counter (16 Hz–2 Hz) can be read by the software.
Figure 4.6.1.1 is the block diagram of the clock timer.
Oscillation
circuit
Normally, this clock timer is used for all kinds of timing purpose, such as clocks.

4.6.2 Interrupt function

The clock timer can generate interrupts at the falling edge of the 32 Hz (or 64 Hz), 16 Hz, and 2 Hz
signals. The software can mask any of these interrupt signals.
Figure 4.6.2.1 is the timing chart of the clock timer.
Register
Address Frequency
bits
D0 16 Hz
8 Hz
D1
0F2H
D2 4 Hz
D3 2 Hz
Occurrence of
32 Hz interrupt request
Occurrence of
16 Hz interrupt request
Occurrence of
2 Hz interrupt request
As shown in Figure 4.6.2.1, an interrupt is generated at the falling edge of the 32 Hz, 16 Hz, and 2 Hz
signals. At this point, the corresponding interrupt factor flag (IT32, IT16, IT2) is set to 1. The interrupts
can be masked individually with the interrupt mask register (EIT32, EIT16, EIT2). However, regardless of
the interrupt mask register setting, the interrupt factor flags will be set to 1 at 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).
Note: Write to the interrupt mask registers (EIT32, EIT16, EIT2) and read the interrupt factor flags (IT32,
IT16, IT2) only in the DI status (interrupt flag = 0). Otherwise, it causes malfunction.
S1C60N03 TECHNICAL MANUAL
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Clock Timer)
256 Hz
Divider
128 Hz–32 Hz
Clock timer reset signal
Fig. 4.6.1.1 Block diagram of clock timer
Fig. 4.6.2.1 Timing chart of the clock timer
Data bus
16 Hz–2 Hz
64 Hz 32 Hz 16 Hz 2 Hz
Mask
option
Interrupt
control
Clock timer timing chart
EPSON
Interrupt
request
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