upd78f0124hgba1-8et-a Renesas Electronics Corporation., upd78f0124hgba1-8et-a Datasheet - Page 226

• Manufacturer Part Number: upd78f0124hgba1-8et-a
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

<R>
12.2 Configuration of A/D Converter
(1) ANI0 to ANI7 pins
(2) Sample & hold circuit
(3) Series resistor string
(4) Voltage comparator
(5) Successive approximation register (SAR)
226
The A/D converter includes the following hardware.
These are the analog input pins of the 8-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 input port pins.
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.
The series resistor string is connected between AV
the analog input signal.
The voltage comparator compares the sampled analog input voltage and the output voltage of the series resistor
string.
This register compares the sampled analog voltage and the voltage of the series resistor string, and converts the
result, starting from the most significant bit (MSB).
When the voltage value is converted into a digital value down to the least significant bit (LSB) (end of A/D
conversion), the contents of the SAR register are transferred to the A/D conversion result register (ADCR).
Registers
AV
AV
Item
Figure 12-2. Circuit Configuration of Series Resistor String
Table 12-1. Registers of A/D Converter Used on Software
REF
SS
A/D conversion result register (ADCR)
A/D converter mode register (ADM)
Analog input channel specification register (ADS)
Power-fail comparison mode register (PFM)
Power-fail comparison threshold register (PFT)
P-ch
CHAPTER 12 A/D CONVERTER
User’s Manual U16962EJ3V0UD
Series resistor string
REF
and AV
Reference voltage
generator
Configuration
SS
, and generates a voltage to be compared with
ADCS
ADCE