UPD78F9234MC-5A4-A Datasheet, PDF (167/419 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

CHAPTER 10 A/D CONVERTER
Figure 10-2 shows the block diagram of A/D converter.
Figure 10-2. Block Diagram of A/D Converter
ANI0/P20
ANI1/P21
ANI2/P22
ANI3/P23
Sample & hold circuit
Voltage comparator
AVSS
Successive
approximation
register (SAR)
D/A converter
AVREF
AVSS
Controller
A/D conversion result register
2
(ADCR, ADCRH)
3
ADS1
Analog input
channel specification
register (ADS)
ADS0
ADCS FR2 FR1 FR0 ADCE
A/D converter mode
register (ADM)
Internal bus
INTAD
10.2 Configuration of A/D Converter
The A/D converter consists of the following hardware.
(1) ANI0 to ANI3 pins
These are the analog input pins of the 4-channel A/D converter. They input analog signals to be converted into
digital signals. Pins other than the one selected as the analog input pin by the analog input channel specification
register (ADS) can be used as I/O port pins.
(2) Sample & hold circuit
The sample & hold circuit samples the input signal of the analog input pin selected by the selector when A/D
conversion is started, and holds the sampled analog input voltage value during A/D conversion.
(3) D/A converter
The D/A converter is connected between AVREF and AVSS, and generates a voltage to be compared with the
analog input signal.
(4) Voltage comparator
The voltage comparator compares the sampled analog input voltage and the output voltage of the D/A converter.
User’s Manual U17446EJ5V0UD
165