CHAPTER 13 A/D CONVERTER
Page 305 of 920
13.5
Input Voltage and Conversion Results
The relationship between the analog input voltage input to the analog input pins and the theoretical A/D conversion
result (stored in the 10-bit A/D conversion result register (ADCR)) is shown by the following expression.
or
where, INT( ): Function which returns integer part of value in parentheses
V
AIN
:
Analog input voltage
AV
REF
: AV
REF
pin voltage
ADCR: A/D conversion result register (ADCR) value
SAR:
Successive approximation register
Figure 13 - 17 shows the Relationship Between Analog Input Voltage and A/D Conversion Result.
Figure 13 - 17 Relationship Between Analog Input Voltage and A/D Conversion Result
Remark
AV
REF
: The + side reference voltage of the A/D converter. This can be selected from AV
REFP
, and V
DD
.
SAR = INT (
×
1024 + 0.5)
ADCR = SAR
×
64
V
AIN
AV
REF
(
−
0.5)
×
≤
V
AIN
< ( + 0.5)
×
ADCR
64
AV
REF
1024
ADCR
64
AV
REF
1024
1
2048
1
1024
3
2048
2
1024
5
2048
3
1024
1023
1022
1021
3
2
1
0
FFC0H
FF80H
FF40H
00C0H
0080H
0040H
0000H
A/D conversion result
SAR
ADCR
Input voltage/AV
REF
1
2043
2048
1022
1024
2045
2048
1023
1024
2047
2048
Summary of Contents for RL78/G1H
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