Programming Notes - Epson S1C63616 Technical Manual

ISIF: Interrupt factor flag (FFFAH•D0)
This flag indicates the occurrence of serial interface interrupt.
When "1" is read:
When "0" is read:
When "1" is written: Flag reset
When "0" is written: No operation
From the status of this flag, the software can decide whether the serial interface interrupt.
This flag is set to "1" after an 8-bit data input/output even if the interrupt is masked.
This flag is reset to "0" by writing "1" to it.
After an interrupt occurs, the same interrupt will occur again if the interrupt enabled state (I flag = "1") is
set or the RETI instruction is executed unless the interrupt factor flag is reset. Therefore, be sure to reset (write
"1" to) the interrupt factor flag in the interrupt service routine before shifting to the interrupt enabled state.
At initial reset, this flag is set to "0".

4.10.9 Programming notes

(1) Perform data writing/reading to the data registers SD0–SD7 only while the serial interface is not run-
ning (i.e., the synchronous clock is neither being input or output).
(2) As a trigger condition, it is required that data writing or reading on data registers SD0–SD7 be per-
formed prior to writing "1" to SCTRG. (The internal circuit of the serial interface is initiated through
data writing/reading on data registers SD0–SD7.) In addition, be sure to enable the serial interface with
the ESIF register before setting the trigger.
Supply trigger only once every time the serial interface is placed in the RUN state. Refrain from per-
forming trigger input multiple times, as leads to malfunctioning. Moreover, when the synchronous
clock SCLK is external clock, start to input the external clock after the trigger.
(3) Setting of the input/output permutation (MSB first/LSB first) with the SDP register should be done
before setting data to SD0–SD7.
(4) Be aware that the maximum clock frequency for the serial interface is limited to 1 MHz when the pro-
grammable timer is used as the clock source or the serial interface is used in slave mode.
(5) After an interrupt occurs, the same interrupt will occur again if the interrupt enabled state (I flag = "1")
is set or the RETI instruction is executed unless the interrupt factor flag is reset. Therefore, be sure to
reset (write "1" to) the interrupt factor flag in the interrupt service routine before shifting to the interrupt
enabled state.
Interrupt has occurred
Interrupt has not occurred
SIC63616-(Rev. 1.0) NO. P134
3240-0412