UPD78F0890GK(A)-GAJ-AX NEC, UPD78F0890GK(A)-GAJ-AX Datasheet - Page 286

• Manufacturer Part Number: UPD78F0890GK(A)-GAJ-AX
• Description: 8BIT MCU, 128K FLASH, 7K RAM, LQFP
• Manufacturer: NEC

Specifications of UPD78F0890GK(A)-GAJ-AX

• Controller Family/series: UPD78F
• No. Of I/o's: 55
• Ram Memory Size: 7KB
• Cpu Speed: 20MHz
• No. Of Timers: 10
• No. Of Pwm: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 128KB
• Oscillator Type: External, Internal

13.2 Configuration of A/D Converter
(1) ANI0 to ANI11 pins
(2) Sample & hold circuit
(3) Series resistor string
(4) Voltage comparator
(5) Successive approximation register (SAR)
(6) 10-bit A/D conversion result register (ADCR)
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The A/D converter includes the following hardware.
These are the analog input pins of the 12-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 can be used as I/O port pins.
The sample & hold circuit samples the input voltage of the analog input pin selected by the selector when A/D
conversion is started, and holds the sampled voltage value during A/D conversion.
The series resistor string is connected between AV
the sampled voltage value.
The voltage comparator compares the sampled voltage value and the output voltage of the series resistor string.
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).
The A/D conversion result is loaded from the successive approximation register to this register each time A/D
conversion is completed, and the ADCR register holds the A/D conversion result in its higher 10 bits (the lower 6
bits are fixed to 0).
Figure 13-2. Circuit Configuration of Series Resistor String
AV
AV
REF
SS
CHAPTER 13 A/D CONVERTER
User’s Manual U17554EJ4V0UD
P-ch
Series resistor string
REF
and AV
SS
, and generates a voltage to be compared with
ADCS