UPD78F1502AGK-GAK-AX Datasheet, PDF (404/1031 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcontrollers

78K0R/Lx3
CHAPTER 10 12-BIT A/D CONVERTER (μ PD78F150xA),
10-BIT A/D CONVERTER (μ PD78F151xA)
10.2 Configuration of A/D Converter
The A/D converter includes the following hardware.
(1) ANI0 to ANI10, ANI15 pins
These are the analog input pins of the A/D converter. They input analog signals to be converted into digital signals.
Pins other than the one selected as the analog input pin can be used as I/O port pins.
Remark 78K0R/LF3:
ANI0-ANI6, ANI15
78K0R/LG3, 78K0R/LH3: ANI0-ANI10, ANI15
(2) Sample & hold circuit
The sample & hold circuit samples each of the analog input voltages sequentially sent from the input circuit, and
sends them to the A/D voltage comparator. This circuit also holds the sampled analog input voltage during A/D
conversion.
(3) Series resistor string
The series resistor string is connected between ADREFP and ADREFM, and generates a voltage to be compared with the
sampled voltage value.
Figure 10-3. Circuit Configuration of Series Resistor String
ADREFP
ADREFM
P-ch
ADCS
Series resistor string
(4) Voltage comparator
The voltage comparator compares the sampled voltage value and the output voltage of the series resistor string.
(5) Successive approximation register (SAR)
This register converts the result of comparison by the voltage comparator, 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).
R01UH0004EJ0501 Rev.5.01
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Jun 20, 2011