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CHAPTER 10 8-BIT A/D CONVERTER (
10.5 Cautions Related to 8-Bit A/D Converter
(1)
Current consumption in standby mode
In standby mode, the A/D converter stops operation. Stopping conversion (bit 7 (ADCS0) of A/D converter
mode register 0 (ADM0) = 0) can reduce the current consumption.
Figure 10-7 shows how to reduce the current consumption in standby mode.
Figure 10-7. How to Reduce Current Consumption in Standby Mode
(2)
Input range for pins ANI0 to ANI5
Be sure to keep the input voltage at ANI0 to ANI5 within the rating. If a voltage not lower than AV
higher than AV
SS
conversion output of the channel becomes undefined, which may affect the conversion output of the other
channels.
(3)
Conflict
<1> Conflict between writing to A/D conversion result register 0 (ADCR0) at the end of conversion and
reading from ADCR0 using instruction
Reading from ADCR0 takes precedence. After reading, the new conversion result is written to ADCR0.
<2> Conflict between writing to ADCR0 at the end of conversion and writing to A/D converter mode register 0
(ADM0) or analog input channel specification register 0 (ADS0)
Writing to ADM0 or ADS0 takes precedence. ADCR0 is not written to. No A/D conversion end interrupt
request signal (INTAD0) is generated.
(4)
Conversion result immediately after start of A/D conversion
The first A/D conversion value immediately after A/D conversion has been started is undefined. Poll the A/D
conversion end interrupt request (INTAD0) and drop the first conversion result.
AV
DD
P-ch
AV
SS
(even within the absolute maximum rating) is input into a conversion channel, the
User's Manual U15075EJ2V1UD
µ
PD789426 AND 789446 SUBSERIES)
ADCS0
Series resistor string
or not
DD
197
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