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3 applying power via the rs-232 connector, 4 configuring rs-232 and i – Matrix Orbital LCD0821 Legacy User Manual

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LCD0821 rev 2

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The RS-232 connector on the PC cable is wired so that a standard “straight through” serial cable may be
used to connect the module to a standard serial port such as COM ports on PCs. Note that this device
complies with the EIA232 standard in that it uses signal levels from ± 3V to ± 12V. It will not operate
correctly at TTL (0 to +5V) levels.

Pin Number

on LCD

Pin Number

on Host

Direction

Description

1 N/A

-

+5Vdc

2

3

to LCD module

Data In

3 5

- Ground

2.1.3 Applying Power via the RS-232 Connector

The power connector on the PC cable is wired as shown in Figure 2-7. Power may be provided to the
module by pin 1 of the 3pin strip header connector instead of through the 4-pin SIP. If power is to be
applied using the 3 pin strip header.

2.1.4 Configuring RS-232 and I

2

C

RS-232 baud rate and I

2

C address are configured by means of jumpers.

Figure 2-8 RS-232 jumpers

The module is supplied with jumpers J1 and J2 installed, which gives a RS-232 baud rate of 19200 and an
I

2

C address of 0x5C.

RS-232 port: J0, J1, J2 - control baud rate. RS-232 format is 8N1 (8 bits, no parity, one stop bit)

I²C port: J0, J1, J2, J3 - sets slave peripheral address

Baud Rate

Slave Address

J3

J2

J1

J0

50H

out out out out

1200

52H

out out out in

54H out

out

in

out

2400

56H out

out

in

in

58H

out in out out

9600

5AH

out in out in

5CH out

in

in

out