UPD78F9234MC-5A4-A Datasheet, PDF (176/419 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

CHAPTER 10 A/D CONVERTER
10.4.2 Input voltage and conversion results
The relationship between the analog input voltage input to the analog input pins (ANI0 to ANI3) and the theoretical
A/D conversion result (stored in the 10-bit A/D conversion result register (ADCR)) is shown by the following
expression.
VAIN
ADCR = INT (
× 1024 + 0.5)
AVREF
or
(ADCR − 0.5) × ^AVREF ≤ VAIN < (ADCR + 0.5) × ^AVREF
1024
1024
where, INT( ): Function which returns integer part of value in parentheses
VAIN: Analog input voltage
AVREF: AVREF pin voltage
ADCR: 10-bit A/D conversion result register (ADCR) value
Figure 10-11 shows the relationship between the analog input voltage and the A/D conversion result.
Figure 10-11. Relationship Between Analog Input Voltage and A/D Conversion Result
SAR
ADCR
1023
03FFH
1022
03FEH
A/D conversion result
1021
3
03FDH
0003H
2
0002H
1
0001H
0
113253
2048 1024 2048 1024 2048 1024
0000H
2043 1022 2045 1023 2047 1
2048 1024 2048 1024 2048
Input voltage/AVREF
174
User’s Manual U17446EJ5V0UD