CHAPTER 12 A/D CONVERTER
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User’s Manual U15109EJ3V0UD
(7) ADCV
DD
pin
The ADCV
DD
pin is the power supply pin of the analog circuit, and also supplies power to the input circuit of ANI0
to ANI11. Even in an application where a back-up power supply is used, therefore, be sure to apply the same
voltage as the V
DD0
pin to the ADCV
DD
pin as shown below.
Figure 12-8. Handling of ADCV
DD
Pin
V
DD0
GND0
ADCV
DD
ADCGND
Main power supply
Back-up
capacitor
(8) Reading out A/D converter result register (ADCR)
Writing to A/D converter mode register 1 (ADM1) and the analog input channel specification register (ADS) may
cause the ADCR contents to be undefined. Therefore, read the conversion result during A/D conversion (ADCS
= 1). Incorrect conversion results may be read if the timing is other than the above.