NJU3505L 查看數據表（PDF） - Japan Radio Corporation

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NJU3505L

4-BIT SINGLE CHIP MICRO CONTROLLER

Japan Radio Corporation  

NJU3505

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

• Reference Voltage

: ±2 LSB (VDD=5V, VREF=5V)

: 2.4V−AVDD

• Analog Input Voltage

: AVSS−VREF

• Channel

: Multiplexed 8-channel Input

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

The lower 2 bits of the A/D converter control register(PHY7) or the lower 1 bit of the A/D control converter

(PHY10) are the switches to select an analog input channel from four multiplexed inputs(AIN0 – AIN7). The

analog input signal to the analog input port selected by the A/D converter control register is converted to the

digital data, and then the digital data is stored into the A/D converter 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 the following

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

4 A/D CONTROL

REGISTER

(PHY10)

(PHY7)

AIN7

AIN6

AIN5

AIN4

AIN3

AIN2

AIN1

AIN0

4

START

CONTROL CIRCUIT

4

EOC

(PHY8)

COMPARATOR

4

Lower side

4bits data

YLSB=“0”

A/D OUTPUT REGISTER

SWITCH TREE

LADDER RESISTOR

PRESCALER

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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