
S1C62N33 TECHNICAL SOFTWARE
EPSON
II-119
CHAPTER 7: SUMMARY OF NOTES
(1) When the I/O port is being read out and the pull-down is
executed only with the built-in pull-down resistor of the
I/O ports, the read-out must be repeated about ten times
when the CPU is operating with the OSC3 oscillation
circuit.
(2) When the I/O port is set to the output mode and the data
register has been read, the pin data instead of the regis-
ter data can be read out. Because of this, if a low-imped-
ance load is connected and read-out performed, the value
of the register and the read-out result may differ.
(1) Correct read-out is impossible when there is a carry from
the low order bit (SWL) to the high order bit (SWH).
Hence, when reading out the counter data in the RUN
status, the counter must first be stopped, and then the
RUN status returned again.
Also, the duration of the above STOP status must be
within 976 s (256 Hz 1/4 cycle).
(2) Resetting the clock timer has no effect on the stopwatch
counter, and vice versa.
(3) Writing to the interrupt mask registers (EISWIT) can be
done only in the DI status (interrupt flag = "0"). Writing
during EI status will cause an error.
Also, when using arithmetic instructions (AND, OR, ADD,
SUB, etc.), pay attention to the control of SVD.
(4) Read out of the interrupt factor flag (SWIT) must be done
only in the DI status (interrupt flag = "0"). Read-out
during EI status will cause an error.
(5) Regardless of the setting of the mask register (EISWIT),
the interrupt factor flag (SWIT) is set to "1" when the
corresponding counter overflows.
To prevent erroneous reading of the event counter data, read
out the counter data multiple times for comparison, and use
the matching data for the result.
– I/O Ports
– Stopwatch Counter
– Event Counter