M16C User Manual.pdf

A-D ConverterMitsubishi microcomputersM16C / 62 GroupSINGLE-CHIP 16-BIT CMOS MICROCOMPUTER2.7.7 Operation of A-D Converter (in single sweep mode)In single sweep mode, choose functions from those listed in Table 2.7.7. Operations of the circled itemsare described below. Figure 2.7.15 shows timing chart, and Figure 2.7.16 shows the set-up procedure.Table 2.7.7. Choosed functionsItemSet-upItemSet-upOperation clock ADODivided-by-4 fAD / dividedby-2fAD / fADTrigger for starting A-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. The A-Dconverter converts all analog input pins selected by the user. The conversion result is transmittedto A-D register i corresponding to each pin, every time conversion on one pin is completed.(3) When the A-D conversion on all the analog input pins selected is completed, the A-D conversioninterrupt request bit goes to “1”. At this time, the A-D conversion start flag goes to “0”.The A-D converter stops operating.(1) Start A-D conversion(2) After A-D conversion on AN0 pin is complete,A-D converter begins converting all pins selected8-bit resolution : 28 φAD cycles10-bit resolution : 33 φAD cycles8-bit resolution : 28 φAD cycles10-bit resolution : 33 φAD cycles(3) A-D conversionis completeφADSet to “1” by softwareA-D conversionstart flag“1”“0”A-D register 0ResultA-D register 1ResultA-D register iResultA-D conversion “1”interrupt request“0”bitCleared to “0” when interrupt request is accepted, or cleared by softwareNote: 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 2.7.15. Operation timing of single sweep mode398