CHAPTER 11 A/D CONVERTER31411.5 Notes on Using A/D Converter(1) Current consumption in standby modeThe A/D converter stops operation in the STOP and IDLE mode (operable at the HALT mode). At this time, thecurrent consumption of the A/D converter can be reduced by stopping the conversion (by resetting the bit 7(ADCS) of the A/D converter mode register (ADM) to 0).To reduce the consumption current during the STOP and IDLE modes, set the AV REF potential in the user circuitto the same value (0 V) as the AV SS potential.(2) Input range of ANI0 through ANI11Keep the input voltage of the ANI0 through ANI11 pins to within the rated range. If a voltage greater than AV REFor lower than AV SS (even within the range of the absolute maximum ratings) is input to a channel, the convertedvalue of the channel becomes undefined. Moreover, the values of the other channels may also be affected.(3) Conflict<1> Conflict between writing A/D conversion result register (ADCR) and reading ADCR at end ofconversionReading ADCR takes precedence. After ADCR has been read, a new conversion result is written to ADCR.<2> Conflict between writing ADCR and external trigger signal input at end of conversionThe external trigger signal is not input during A/D conversion. Therefore, the external trigger signal is notaccepted during writing of ADCR.<3> Conflict between writing of ADCR and writing A/D converter mode register (ADM) or analog inputchannel specification register (ADS)When ADM or ADS write is performed immediately after ADCR write following A/D conversion end, theconversion result is written to the ADCR register, but the timing is such that INTAD is not generated.
