Input Voltage And Conversion Results - NEC 78K0S/KU1+ User Manual

9.4.2

Input voltage and conversion results

The relationship between the analog input voltage input to the analog input pins (ANI0 to ANI3) and the theoretical
A/D conversion result (stored in the 10-bit A/D conversion result register (ADCR)) is shown by the following
expression.
V
AIN
ADCR = INT (
V
DD
or
V
DD
(ADCR − 0.5) ×
1024
where, INT( ): Function which returns integer part of value in parentheses
V : Analog input voltage
AIN
V : V pin voltage
DD DD
ADCR: 10-bit A/D conversion result register (ADCR) value
Figure 9-11 shows the relationship between the analog input voltage and the A/D conversion result.
Figure 9-11. Relationship Between Analog Input Voltage and A/D Conversion Result
A/D conversion result
CHAPTER 9 A/D CONVERTER
× 1024 + 0.5)
≤ V < (ADCR + 0.5) ×
AIN
1024
SAR
1023
1022
1021
3
2
1
0
1 1
2048 1024 2048
User's Manual U18172EJ2V0UD
V
DD
3 2 5 3 2043 1022
1024 2048 1024 2048 1024
Input voltage/V
DD
ADCR
03FFH
03FEH
03FDH
0003H
0002H
0001H
0000H
2045 1023 2047 1
2048 1024 2048
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