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CHAPTER 12 A/D CONVERTER
User’s Manual U19780EJ2V0UD
342
12.4.3 A/D converter operation mode
The operation mode of A/D converter has the following four functions.
•
Software trigger mode (continuously convert mode)
•
Software trigger mode (single convert mode)
•
Timer trigger mode (continuously convert mode)
•
Timer trigger mode (single convert mode)
(1) Software trigger mode (continuously convert mode)
<1>
By setting bit 7 (ADCS) of the A/D converter mode register (ADM) to 1, the A/D conversion operation of the
voltage, which is applied to the analog input pin specified by the analog input channel specification register
(ADS), is started.
<2>
When A/D conversion has been completed, the result of the A/D conversion is stored in the A/D conversion
result register (ADCR, ADCRH), and an interrupt request signal (INTAD) is generated. When one A/D
conversion has been completed, the next A/D conversion operation is immediately started. .
<3>
If 1 is written to ADCS during A/D conversion, the A/D conversion operation under execution is stopped and
restarted from the beginning. At this time, the conversion result immediately before is retained.
<4> If ADS is rewritten during A/D conversion, the A/D conversion operation under execution is stopped and
restarted from the beginning. At this time, the conversion result immediately before is retained.
<5>
If 0 is written to ADCS during A/D conversion, A/D conversion is immediately stopped. At this time, the
conversion result immediately before is retained.
Figure 12-15. Software Trigger Mode (continuously convert mode)
ANIn
<1>
ADCS
=
1
ANIn
ANIn
ANIm
ANIn
ANIm
ANIm
Stopped
ADCR,
ADCRH
INTAD
ADCS
<3>
ADCS
=
1
<5>
ADCS
=
0
A/D conversion
<4> Rewriting ADS
<2> A/D conversion
end
<2> A/D conversion
end
Conversion is stopped
Conversion starts from
beginning
Conversion is stopped
Conversion starts from
beginning
Remark
78K0/KB2-A: n = 0 to 5, 8 to 11, m = 0 to 5, 8 to 11
78K0/KC2-A: n = 0 to 6, 8 to 11, 15, m = 0 to 6, 8 to 11, 15