A/D Conversion By Software Start - NEC mPD780208 Subseries User Manual

(2) A/D conversion by software start

When bit 6 (TRG) and bit 7 (CS) of the A/D converter mode register (ADM) are set to 0 and 1, respectively,
A/D conversion starts on the voltage applied to the analog input pins specified by bits 1 to 3 (ADM1 to
ADM3) of ADM.
At the end of A/D conversion, the conversion result is stored in the A/D conversion result register (ADCR)
and the interrupt request signal (INTAD) is generated. After one A/D conversion operation is started and
terminated, the next A/D conversion operation starts immediately. A/D conversion continues repeatedly
until new data is written to ADM.
If data with CS set to 1 is written to ADM again during A/D conversion, the converter suspends its A/D
conversion operation and starts A/D conversion on the newly written data.
If data with CS set to 0 is written to ADM during A/D conversion, the A/D conversion operation stops
immediately.
Conversion start
CS = 1, TRG = 0
A/D conversion
ADCR
INTAD
Remark n = 0, 1, ... , 7
m = 0, 1, ... , 7
CHAPTER 12 A/D CONVERTER
Figure 12-7. A/D Conversion by Software Start
ANIn ANIn
Conversion suspended
Conversion results
are not stored
ANIn
User's Manual U11302EJ4V0UM
ADM rewrite ADM rewrite
CS = 1, TRG = 0 CS = 0, TRG = 0
ANIn ANIm ANIm
ANIn
Stop
ANIm
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