CHAPTER 12 A/D CONVERTER
199
User’s Manual U11302EJ4V0UM
12.4.2 Input voltage and conversion results
The relationship between the analog input voltage input to the analog input pins (ANI0 to ANI7) and the A/
D conversion result (the value stored in the A/D conversion result register (ADCR)) is shown by the following
expression.
V
IN
ADCR = INT(
×
256 + 0.5)
AV
REF
or
AV
REF
AV
REF
(ADCR – 0.5)
×
≤
V
IN
< (ADCR + 0.5)
×
256
256
Remark
INT ( ): Function which returns the integer part of the value in parentheses
V
IN
:
Analog input voltage
AV
REF
:
AV
REF
pin voltage
ADCR:
A/D conversion result register (ADCR) value
Figure 12-5 shows the relationship between the analog input voltage and the A/D conversion result.
Figure 12-5. Relationship Between Analog Input Voltage and A/D Conversion Result
1
512
1
256
3
512
2
256
5
512
3
256
507
512
254
256
509
512
255
256
511
512
1
0
1
2
3
253
254
255
A/D
conversion
results
(ADCR)
Input voltage/AV
REF
Содержание mPD780204
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