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CHAPTER 13 10-BIT A/D CONVERTER (
µ
PD780354, 780354Y SUBSERIES)
User’s Manual U15798EJ2V0UD
13.4.2 Input voltage and conversion results
The relationship between the analog voltage input to the analog input pins (ANI0 to ANI7) and the logical A/D
conversion result (stored in A/D conversion result register 0 (ADCR0)) is shown by the following expression.
ADCR0 = INT (
V
IN
×
1,024 + 0.5)
AV
DD
or
(ADCR0 – 0.5)
×
AV
DD
≤
V
AIN
< (ADCR0 + 0.5)
×
AV
DD
1,024
1,024
where,
INT( ):
Function which returns integer part of value in parentheses
V
AIN
:
Analog input voltage
AV
DD
:
AV
DD
pin voltage
ADCR0: A/D conversion result register 0 (ADCR0) value
Figure 13-6 shows the relationship between the analog input voltage and the A/D conversion result.
Figure 13-6. Relationship Between Analog Input Voltage and A/D Conversion Result
1,023
1,022
1,021
3
2
1
0
A/D conversion result
(ADCR0)
1
2,048
1
1,024
3
2,048
2
1,024
5
2,048
3
1,024
2,043
2,048
1,022
1,024
2,045
2,048
1,023
1,024
2,047
2,048
1
Input voltage/AV
DD
Содержание mPD780344 Series
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