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RL78/G1A CHAPTER 11 A/D CONVERTER
R01UH0305EJ0200 Rev.2.00 371
Jul 04, 2013
11.5 Input Voltage and Conversion Results
The relationship between the analog input voltage input to the analog input pins (ANI0 to ANI12, ANI16 to ANI30) 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: AVREF pin voltage
ADCR: A/D conversion result register (ADCR) value
Figure 11-16 shows the relationship between the analog input voltage and the A/D conversion result.
Figure 11-16. 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 AVREF: The + side reference voltage of the A/D converter. This can be selected from AVREFP, the internal
reference voltage (1.45 V), and AV
DD.
V
AIN
AV
REF
AVREF
4096
AVREF
4096