Chapter 14A/D ConverterXIV - 28 Operation■ Setting Sampling/Hold TimeSampling/hold time can be selected from 1, 2 , 4 and 6 cycles of the conversion clock. Select the proper valuewith the A/D input impedance. If the A/D input impedance is high, select 6 cycles.■ Selecting Operation ModeOperation mode is set by the AN0MD1-0 flags of the AN0CTR0 register and the AN1MD1-0 flags of theAN1CTR0 register and the AN2MD1-0 flags of the AN2CTR0 register. Table: 14.3.2 shows the operation modeto be set. One-time conversion means that one-time input to the ADINn pin is converted by the any single channelor multiple channels. Continuous conversion means that the conversion is continued until it is stopped by the anysingle channel or multiple channels.Table:14.3.2 Operation Mode of A/D Conversion■ A/D Converter StartA/D conversion is started when the set-up start trigger is generated.Table:14.3.3 Converter Start Trigger (AD0, 1, 2)■ A/D Converter StopA/D converter stop differs depending on the conversion mode to be selected.Table:14.3.4 A/D Converter StopANnMD1 ANnMD0 Operation mode0 0 Any single channel/one-time conversion0 1 Multiple channels/one-time conversion for each1 0 Any single channel/continuous conversion1 1 Multiple channels/continuous conversionStart trigger AN0TRG(AN0CTR)ADnAST2-0(ADSTn)ANnTRGB(ANnCTR1 DescriptionRegister set by instruction 0 - - Conversion is started by setting the ANnEN flag of the conver-sion control register (ANnCTR0) to “1”.PWM0 overflow 1 000 1 Conversion is started by PWN0 overflow signal.PWM0 underflow 1 001 1 Conversion is started by PWN0 underflow signal.Timer 12 compare A 1 010 1 Conversion is started by the timer 12 compare A interrupt.Timer 12 compare B 1 011 1 Conversion is started by the timer 12 compare B interrupt.PWM1 overflow 1 100 1 Conversion is started by PWN1 overflow signal.PWM1 underflow 1 101 1 Conversion is started by PWN1 underflow signal.Timer 13 compare A 1 110 1 Conversion is started by the timer 13 compare A interrupt.Timer 13 compare B 1 111 1 Conversion is started by the timer 13 compare B interrupt.Operation mode Stop operationAny single channel/one time con-version When one-time conversion ends, all the conversion operation is completed and the con-version operation is stopped.Multiple channels/one time con-version for eachAny single channel/continuousconversion The conversion operation is not stopped even if one-time conversion ends. To stop theconversion, the ANnEN flag needs to be cleared to “0”.Multiple channels/continuousconversion
