RL78/G1P
CHAPTER 9 A/D CONVERTER
R01UH0895EJ0100 Rev.1.00
270
Nov 29, 2019
9.5 Input Voltage and Conversion Results
The relationship between the analog input voltage input to the analog input pins (ANI0 to ANI7, ANI16) 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
(ADCR - 0.5)
V
AIN
< (ADCR + 0.5)
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
Figure 9-16 shows the relationship between the analog input voltage and the A/D conversion result.
Figure 9-16. 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
Remark
AV
REF
: The + side reference voltage of the A/D converter. This can be selected from AV
REFP
, the internal
reference voltage (1.45 V), and V
DD
.
V
AIN
AV
REF
AV
REF
4096
AV
REF
4096