Programming Notes - Epson E0C6006 Technical Manual

IT32, IT8, IT2: Interrupt factor flags (0F1H•D0–D2)
These flags indicate the status of the clock timer interrupt.
When "1" is read: Interrupt has occurred
When "0" is read: Interrupt has not occurred
Writing: Invalid
The interrupt factor flags (IT32, IT8, IT2) correspond to the clock timer interrupts (32 Hz, 8 Hz, 2 Hz). The
software can determine from these flags whether there is a clock timer interrupt. However, even if the
interrupt is masked, the flags are set to "1" at the falling edge of the signal. These flags can be reset when
the register is read by the software.
Reading of interrupt factor flags is available at EI, but be careful in the following cases.
If the interrupt mask register value corresponding to the interrupt factor flag to be read is set to "1", an
interrupt request will be generated by the interrupt factor flag set timing, or an interrupt request will not
be generated. Be very careful when interrupt factor flags are in the same address.
At initial reset, these flags are set to "0".

4.8.4 Programming notes

(1) Note that the frequencies and times differ from the description in this section when the oscillation
frequency is not 32.768 kHz.
(2) Reading of interrupt factor flags is available at EI, but be careful in the following cases.
If the interrupt mask register value corresponding to the interrupt factor flag to be read is set to "1", an
interrupt request will be generated by the interrupt factor flag set timing, or an interrupt request will
not be generated. Be very careful when interrupt factor flags are in the same address.
E0C6006 TECHNICAL MANUAL
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Clock Timer)
EPSON
29