Programming Notes - Epson S1C6S3N2 Technical Manual

CHAPTER 5: PERIPHERAL CIRCUITS (Stopwatch Counter)

Programming notes

II-96
(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 µs (256 Hz 1/4 cycle).
(2) Resetting the clock timer has no effect on the stopwatch
counter, and vice versa.
(3) When using arithmetic instructions (AND, OR, ADD,
SUB, etc.) for writing to the interrupt mask registers
(EISWIT), pay attention to the control of BLD.
(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
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.
(5) Regardless of the setting of the mask register (EISWIT),
the interrupt factor flag (SWIT) is set to "1" when the
corresponding counter overflows.
EPSON
S1C6S3N2 TECHNICAL SOFTWARE