Renesas RL78 Series User Manual page 360

RL78/G1D
12.5 Input Voltage and Conversion Results
The relationship between the analog input voltage input to the analog input pins (ANI0 to ANI3 and ANI16 to ANI19)
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
SAR = INT (
AV
REF
ADCR = SAR × 64
or
ADCR
AV
( – 0.5) ×
64
1024
where, INT( ): Function which returns integer part of value in parentheses
V : Analog input voltage
AIN
AV : AV
REF REF
ADCR: A/D conversion result register (ADCR) value
SAR: Successive approximation register
Figure 12-16 shows the relationship between the analog input voltage and the A/D conversion result.
Figure 12-16. Relationship Between Analog Input Voltage and A/D Conversion Result
A/D conversion result
Remark AV
R01UH0515EJ0120 Rev.1.20
Dec 16, 2016
× 1024 + 0.5)
ADCR
REF
V < ( + 0.5) ×
≤
AIN
64
pin voltage
SAR
1023
1022
1021
3
2
1
0
1
2048
: The + side reference voltage of the A/D converter. This can be selected from AV
REF
the internal reference voltage (1.45 V), and V
AV
REF
1024
1 3 2 5 3 2043
1024 2048 1024 2048 1024 2048
Input voltage/AV
CHAPTER 12 A/D CONVERTER
ADCR
FFC0H
FF80H
FF40H
00C0H
0080H
0040H
0000H
1022 2045 1023 2047 1
1024 2048 1024 2048
REF
.
DD
,
REFP
339