CHAPTER 11 A/D CONVERTERUser’s Manual U16227EJ2V0UD 235(8) Conversion timeThis expresses the time since sampling has been started until digital output is obtained.The sampling time is included in the conversion time in the characteristics table.(9) Sampling timeThis is the time the analog switch is turned on for the analog voltage to be sampled by the sample & hold circuit.Samplingtime Conversion time11.6 Cautions for A/D Converter(1) Operating current in standby modeThe A/D converter stops operating in the standby mode. At this time, the operating current can be reduced byclearing bit 7 (ADCS) of the A/D converter mode register (ADM) to 0.Figure 11-18 shows the circuit configuration of series resistor string.Figure 11-18. Circuit Configuration of Series Resistor StringAVREFAVSSP-chSeries resistor stringADCS(2) Input range of ANI0 to ANI7Observe the rated range of the ANI0 to ANI7 input voltage. If a voltage of AVREF or higher and AV SS or lower(even in the range of absolute maximum ratings) is input to an analog input channel, the converted value of thatchannel becomes undefined. In addition, the converted values of the other channels may also be affected.(3) Conflicting operations<1> Conflict between A/D conversion result register (ADCR) write and ADCR read by instruction upon the endof conversionADCR read has priority. After the read operation, the new conversion result is written to ADCR.<2> Conflict between ADCR write and A/D converter mode register (ADM) write or analog input channelspecification register (ADS) write upon the end of conversionADM or ADS write has priority. ADCR write is not performed, nor is the conversion end interrupt signal(INTAD) generated.