A/D Conversion End Interrupt Request Generation Timing - NEC mPD780208 Subseries User Manual

(6) Interrupt request flag (ADIF)
The interrupt request flag (ADIF) is not cleared even if the A/D converter mode register (ADM) is changed.
Therefore, if an analog input pin is changed during A/D conversion, the A/D conversion result for the
analog input before changing and ADIF may be set immediately before rewriting ADM. In this case, if
ADIF is read immediately after the rewriting of ADM, ADIF is set despite the fact that A/D conversion of
the analog input after changing has not been completed (refer to Figure 12-10).
When A/D conversion is stopped, ADIF must be cleared before restarting.
Figure 12-10. A/D Conversion End Interrupt Request Generation Timing
ADM rewrite
(start of ANIn conversion)
A/D conversion
ADCR
INTAD
Remark n = 0, 1, ... , 7
m = 0, 1, ... , 7
(7) AV pin
DD
The AV pin is the analog circuit power supply pin, and supplies power to the input circuits of ANI0/P10
DD
to ANI7/P17.
Therefore, be sure to apply the voltage at the same level as V
application where the power supply is switched to the back-up power supply.
Main power supply
204
CHAPTER 12 A/D CONVERTER
ADM rewrite
(start of ANIm conversion)
ANIn ANIn
ANIn
Figure 12-11. AV
User's Manual U11302EJ4V0UM
ADIF is set but ANIm
conversion has not ended
ANIm
ANIn
as shown in Figure 12-11 even in an
DD
Pin Connection
DD
AV
REF
V
DD
AV
DD
Back up
capacitor
V
SS
AV
SS
ANIm
ANIm ANIm