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CHAPTER 12 A/D CONVERTER
User’s Manual U19780EJ2V0UD
341
12.4.2 Input voltage and conversion results
The relationship between the analog input voltage input to the analog input pins (ANI0 to ANI6, ANI8 to ANI11, and
ANI15) and the theoretical A/D conversion result (stored in the 12-bit A/D conversion result register (ADCR)) is shown by
the following expression.
ADCR = INT(
×
4096 + 0.5)
or
(
−
0.5)
×
≤
V
AIN
< ( + 0.5)
×
where, INT( ): Function which returns integer part of value in parentheses
V
AIN
:
Analog input voltage
AV
REF
: Conference voltage of A/D converter
ADCR: 12-bit A/D conversion result register (ADCR) value
Remark
78K0/KB2-A : ANI0 to ANI5, ANI8 to ANI11
78K0/KC2-A : ANI0 to ANI6, ANI8 to ANI11, ANI15
Figure 12-14 shows the relationship between the analog input voltage and the A/D conversion result.
Figure 12-14. Relationship Between Analog Input Voltage and A/D Conversion Result
4095
4094
4093
3
2
1
0
0FFFH
0FFEH
0FFDH
0003H
0002H
0001H
0000H
A/D conversion result
SAR
ADCR
1
8192
1
4096
3
8192
2
4096
5
8192
Input voltage/AV
REF
3
4096
8187
8192
4094
4096
8189
8192
4095
4096
8191
8192
1
V
AIN
AV
REF
AV
REF
4096
AV
REF
4096
ADCR
ADCR