NJU3504FA1 查看數據表（PDF） - Japan Radio Corporation

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NJU3504FA1

4-BIT SINGLE CHIP MICRO CONTROLLER

Japan Radio Corporation  

NJU3504

s A/D CONVERTER

The A/D converter operates with the following specification.

• A/D Conversion

: Successive Approximation method

• Minimum conversion Time

: 40µsec (VDD=5V, VREF=5V, fADCK=225kHz)

• Resolution

: 8 bit (256 step)

• Absolute Accuracy

: ±2 LSB (VDD=5V, VREF=5V)

• Reference Voltage

• Analog Input Voltage

• Channel

: 2.4V−AVDD

: AVSS −VREF

: Multiplexed 4-channel Input

The A/D converter block diagram and the timing chart are shown below.

The lower 2 bits of the A/D control register are the switches to select an analog input channel from four

multiplexed inputs(AIN0 to AIN3). The analog input signal to the analog input port selected by the A/D control

register is converted to the digital data, and then the digital data is stored into the A/D output register(PHY8).

The A/D control clock can selected either the external clock or the internal by the mask option. In the

external clock operation, the input clock from the “ADCK” terminal operates as the A/D control clock. In the

internal clock operation, the clock divided in the internal Prescaler operates as the A/D control clock. The

frequency of the clock from the internal Prescaler can be selected by the mask option from follows which are

dividing numbers based on the inverse of one instruction execution time(1/fOSC X 6).

1/2, 1/4, 1/8, 1/16, 1/32,1/64, 1/128, 1/256, 1/512, 1/1024, 1/2048, 1/4096

[A/D CONVERTER BLOCK DIAGRAM]

DB

PRESCALER

A/D CONTROL 4

REGISTER

START

CONTROL CIRCUIT

4

4

EOC

COMPARATOR

Upper side

4bit data

YLSB=“1”

Lower side

4bit data

YLSB=“0”

AIN3

AIN2

A/D OUTPUT REGISTER

AIN1

AIN0

SWITCH TREE

LADDER RESISTOR

AVSS

VREF

ADCK

Remarks) The A/D control clock can be selected either the external clock from the ADCK terminal or the internal

clock from the Prescaler by the mask option. The Prescaler supplies clocks to Timer/Counter, Serial

Input Output, and A/D converter.

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