UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 415

• Manufacturer Part Number: UPD784026
• Description: 16/8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

(1) Input circuit
(2) Sample & hold circuit
(3) Voltage comparator
(4) Series resistor string
Cautions 1. A capacitor should be connected between the analog input pins (ANI0 to ANI7) and AV
The input circuit selects the analog input in accordance with the specification of the A/D converter mode register (ADM),
and sends the analog input to the sample & hold circuit according to the operating mode,
The sample & hold circuit samples the analog inputs arriving sequentially one by one and holds the analog input in
the process of A/D conversion.
The voltage comparator determines the voltage difference between the analog input and the series resistor string value
tap.
The series resistor string is used to generate voltages that match the analog inputs.
The series resistor string is connected between the A/D converter reference voltage pin (AV
GND pin (AV
two resistors with half that resistance value.
The series resistor string voltage tap is selected by a tap selector controlled by the successive approximation register
(SAR).
2. A voltage outside the range AV
SS
between the reference voltage input pin (AV
Be sure to connect the capacitor as closely to ANI0 through ANI7 and AV
input pins. See 14.5 CAUTIONS for details.
). To provide 256 equal voltage steps between the two pins, it is made up of 255 equal resistors and
Figure 14-2 Example of Capacitor Connection on A/D Converter Pins
Voltage Input
Reference
Analog
Input
CHAPTER 14 A/D CONVERTER
100 to
500 pF
SS
to AV
REF1
should not be applied to pins used as A/D converter
REF
ANI0-ANI7
AV
AV
) and AV
REF1
SS
PD784026
SS
to prevent misoperation due to noise.
REF1
REF1
) and the A/D converter
as possible.
SS
375
and