Specifications

Table Of Contents
S1C62740 TECHNICAL HARDWARE EPSON I-69
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Programmable Timer)
IPT:
Interrupt factor flag
(C0HD0)
This is the interrupt factor flag of the programmable timer.
When "1" is read: Interrupt has occurred
When "0" is read: Interrupt has not occurred
Writing: Invalid
From the status of this flag, the software can decide whether the
programmable timer interrupt. Note, however, that even if the
interrupt is masked, this flag will be set to "1" by the counter value
will become "00H".
This flag is reset when read out 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 flags to be read is set to "1", an interrupt request will be
generated by the interrupt factor flags set timing, or an interrupt
request will not be generated.
At initial reset, this flag is set to "0".
Programming notes
(1) Be sure to data reading in the order of low-order data (PT0–PT3)
then high-order data (PT4–PT7).
(2) When data of reload registers is set at "00H", the down-counter
becomes a 256-value counter.
(3) Write the interrupt mask register (EIPT) only in the DI status
(interrupt flag = "0"). Writing during EI status (interrupt flag =
"1") will cause malfunction.
(4) 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 inter-
rupt factor flags to be read is set to "1", an interrupt request will
be generated by the interrupt factor flags set timing, or an
interrupt request will not be generated.