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Part Number SER7

Copyright © 2014 ABCircuits. Revised September 2014 Page 4 of 11

POL

Polarity input. If this pin is open or high, the “on” segments will have a high level on the SEG

outputs of the chip. If this pin is low or grounded “on” segments will output as a low on the SEG

pins. This pin is read once at power up and has a built in pull up resistor.

DP

Right or left hand decimal input. This pin should be open for right hand decimal displays or

grounded for left hand decimal displays. This pin is read once at power up and has a built in pull

up resistor.

JUST

Justification input. If this pin is open, the data received will be displayed right justified. If this pin

is low or grounded, the data received will be displayed left justified. This pin is read once at

power up and has a built in pull up resistor. See also the expansion examples.

SIN-

This is the serial input pin. It may be tied directly to the UART transmitter output of your UART or

microprocessor; to a RS -232 receiver such as the MAX232; an Ethernet interface such as the

Lantronix Xport; or a USB IC such as the FT232. This pin is high in the idle state, the input

format is 8 bits, 1 stop, no parity at 9600 BPS. Other formats and baud rates are available,

please contact the factory for information.

This pin does not have an internal pull up resistor. It is recommended your software periodically

send the data to the displays to recover from communications errors or power failures. You can

drive this input with any terminal program like REALTERM or HYPERTERM for testing and

development.

ADR0-3

These pins determine the device address. Up to 16 devices can be used on the same

communications channel, either on the same board, or on separate boards if a multi-drop

interface such as RS -485 is used. See the example circuits for expansion details.

Note that the JUST pin controls the placement of device address 0. If the pin is low, (left justify)

the Address 0 is on the left end of the chain, and the addresses increase going right. If this pin is

open or high, (right justify) the address 0 is on the right side, and addresses increase going left.