
I-100
EPSON
S1C62740 TECHNICAL HARDWARE
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (A/D Converter)
IAD:
Interrupt factor flag
(C4HD0)
This flag indicates interrupt caused by the A/D converter.
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 an A/
D interrupt has occurred.
This flag is reset when the software has read it.
Reading of interrupt factor flag is available at EI, but be careful in
the following cases.
If the interrupt mask register value corresponding to the interrupt
factor flag to be read is set to "1", an interrupt request will be
generated by the interrupt factor flag set timing, or an interrupt
request will not be generated.
At initial reset, this flag is set to "0".
Programming notes
(1) To reduce current consumption, set the reference voltage
generation circuit, the middle electric potential generation
circuit and the A/D converter to OFF when it is not necessary.
(2) Do not fail to select the correct combinations for the analog
input terminal and measurement items. (Refer to Table 4.12.1)
(3) To perform a stable A/D conversion, secure the decided wait
time.
(4) Be sure to check whether the data is effective or invalid by
reading the A/D conversion data in the order F7H
→ F8H →
F9H
→ FAH and immediately thereafter reading the IDR (FBH).
(5) When reading data after turning the A/D converter OFF, the A/
D converter should be OFF in the period from an interrupt
generation to the beginning of a reverse integration.
(6) When the A/D converter is reset or turned OFF, the interrupt
factor flag (IAD) may sometimes be set to "1". Consequently,
read the flag (reset the flag) as necessary at reset or at the
turning OFF.
(7) Write the interrupt mask register (EIAD) only in the DI status
(interrupt flag = "0"). Writing during EI status (interrupt flag =
"1") will cause malfunction.
(8) Reading of interrupt factor flag is available at EI, but be careful
in the following cases.
If the interrupt mask register value corresponding to the inter-
rupt factor flag to be read is set to "1", an interrupt request will
be generated by the interrupt factor flag set timing, or an
interrupt request will not be generated.