II-38
EPSON
S1C621A0 TECHNICAL SOFTWARE
CHAPTER 2: PERIPHERAL CIRCUITS (Remote-control LEDs)
tRIC
Write data
to register
τ-waveform
REM interrupt
Fig. 2.7.6
REM Interrupt Timing
In Figure 2.7.6, a REM interrupt occurs at the timing
TRIC set in the RIC register.
Once data has been set in the RIC register, avoid writing
data again into the register before a REM interrupt oc-
curs, as this may cause an invalid interrupt.
The values allowed for the RIC register are 0 to 0EH.
EIREM
The EIREM register controls REM interrupt masking. To
output REM data using an interrupt under hardware
timer control, set the EIREM register to 1. Set it to 0 after
completion of the REM output.
IREM
This register is the flag which is set when a REM inter-
rupt occurs. Whether or not a REM interrupt has oc-
curred can be identified by software. The flag is reset by
reading it.
Read the IREM flag must be read in DI status (interrupt
flag = 0). 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. Be
very careful when interrupt factor flags are in the same
address.
For details on the EIREM and IREM, see section 2.9,
"Interrupt and Halt".
The registers described above are used under hardware
timer control. To program remote-control transmission
waveforms under hardware timer control, set ROUT and
RIC with the REM interrupt routine and repeat opera-
tions as many times as the total bits making up the
transmission data.