M16C User Manual.pdf

A-D ConverterMitsubishi microcomputersM16C / 62 GroupSINGLE-CHIP 16-BIT CMOS MICROCOMPUTER2.7.8 Operation of A-D Converter (in repeat sweep mode 0)In repeat sweep 0 mode, choose functions from those listed in Table 2.7.8. Operations of the circled itemsare described below. Figure 2.7.17 shows timing chart, and Figure 2.7.18 shows the set-up procedure.Table 2.7.8. Choosed functionsItemSet-upItemSet-upOperation clock ADODivided-by-4 fAD / dividedby-2fAD / fADTrigger for startingA-D conversionOSoftware triggerTrigger by ADTRGResolutionAnalog input pinOO8-bit / 10-bitAN0 and AN1 (2 pins) / AN0to AN3 (4 pins) / AN0 to AN5(6 pins) / AN0 to AN7 (8 pins)Expanded analoginput pinSample & HoldONot usedExternal ope-ampconnection modeNot activatedOActivatedOperation(1) Setting the A-D conversion start flag to “1” causes the A-D converter to start the conversionon voltage input to the AN0 pin.(2) After the A-D conversion of voltage input to the AN0 pin is completed, the content of thesuccessive comparison register (conversion result) is transmitted to A-D register 0.(3) The A-D converter converts all pins selected by the user. The conversion result is transmittedto A-D register i corresponding to each pin every time A-D conversion on the pin is completed.The A-D conversion interrupt request bit does not go to “1”.(4) The A-D converter continues operating until the A-D conversion start flag is set to “0” bysoftware.(1) Start A-D conversion8-bit resolution : 28 φAD cycles10-bit resolution : 33 φAD cycles(2) AN1 conversion begins after AN0conversion is complete(3) Consecutive conversion8-bit resolution : 28 φAD cycles10-bit resolution : 33 φAD cycles(4) A-D conversionis completeφADSet to “1” by software.Cleared to “0” by softwareA-Dconversionstart flag“1”“0”A-D register 0ResultA-D register 1ResultA-D register iResultNote: When φAD frequency is less than 1MHZ, sample and hold function cannot be selected.Conversion rate per analog input pin is 49 φAD cycles for 8-bit resolution and 59 φAD cycles for 10-bit resolution.Figure 2.7.17. Operation timing of repeat sweep 0 mode400