IBM uPD78082 User Manual
Page 156
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CHAPTER 10 A/D CONVERTER
A /D Conversion
ADCR
INTAD
ANIn
ANIn
ANIm
ANIm
ANIn
ANIn
ANIm
ANIm
ADM Rewrite
(Start of ANIn Conversion)
ADM Rewrite
(Start of ANIm Conversion)
ADIF is set but ANIm
conversion has not ended
(6) Interrupt request flag (ADIF)
The interrupt request flag (ADIF) is not cleared even if the A/D converter mode register (ADM) is changed.
Caution is therefore required since, if a change of analog input pin is performed during A/D conversion, the
A/D conversion result and ADIF for the pre-change analog input may be set just before the ADM rewrite, and
when ADIF is read immediately after the ADM rewrite, ADIF may be set despite the fact that the A/D conversion
for the post-change analog input has not ended.
When the A/D conversion is stopped and then resumed, clear the ADIF before it is resumed.
Figure 10-11. A/D Conversion End Interrupt Request Generation Timing
(7) AV
DD
pin
The AV
DD
pin is the analog circuit power supply pin, and supplies power to the input circuits of ANI0/P10 to
ANI7/P17.
Therefore, be sure to apply the same voltage as V
DD
to this pin shown in the following figure even when the
application circuit is designed so as to switch to a backup battery.
Figure 10-12. Handling of AV
DD
Pin
Main
power
supply
AV
REF
V
DD
AV
DD
AV
SS
V
SS
Capacitor
for back-up