CHAPTER 12 A/D CONVERTER
User’s Manual U15109EJ3V0UD
463
12.4.2 Input voltage and conversion result
The analog voltages input to the analog input pins (ANI0 to ANI11) and the result of the A/D conversion (contents
of the A/D conversion result register (ADCR)) are related as follows:
ADCR = INT(
×
1024 + 0.5)
Or,
(ADCR
−
0.5)
×
≤
V
IN
< (ADCR + 0.5)
×
INT ( ):
Function that returns integer of value in ( )
V
IN
:
Analog input voltage
ADCV
DD
: A/D converter reference voltage
ADCR:
Value of the A/D conversion result register (ADCR)
The relationship between the analog input voltage and A/D conversion result is shown below.
Figure 12-3. Relationship Between Analog Input Voltage and A/D Conversion Result
1
1
3
2
5
3
2043 1022 20451023 2047
1
2048 1024 20481024 2048 1024
2048 1024 20481024 2048
0
1
2
3
1021
1022
1023
A/D conversion result
(ADCR)
Input voltage/ADCV
DD
V
IN
ADCV
DD
ADCV
DD
1024
ADCV
DD
1024