Asked — Edited


Hello everyone, I have another question.

I have this neat little serial 2x8 lcd screen. Its got this rs-232 port with a gnd, 5v, and rx pin. I think I have this lcd connected accordingly. gnd on gnd pin, 5v on 5vpin, and rx on I/O pin. I then send a " sendserial(d15, 9600, "hi") " and i get all kinds of weird symbols. Ive tried sending hexidecimal commands like " sendserial(d15, 9600, 0xFE, 0x46) " to try n turn it off according to its manual and the same symbols pop out..looks like nothing realy. So I'm sure im doing something wrong, I just dont know what yet.

theres also a serial port with gnd, 5v, rx, tx, should i be using those instead n use d16's I/o pin for the tx?

Any help would be appreciated. :)


Upgrade to ARC Pro

Experience early access to the latest features and updates. You'll have everything that is needed to unleash your robot's potential.



The display is a Matrix Orbital LCD. It has I2c, rs232 and TTL connections. Right now its connected with a 3 wire rs232 connection (pwr, gnd and rx). I've read through the manual to find out about the various codes for turning the display on and off or setting autoscroll functions on/off. Included example for autoscroll on:

Syntax Hexadecimal: 0xFE 0x51 Decimal: 254 81 ASCII: 254 "Q" Remembered: Yes Default: On

I've tried sending various codes. The default baudrate of this LCD is 19200 so I send a code like "sendserial(d15, 19200, 0xfe, 0x51)". Regardless of the codes or commands that I try to send, I get weird looking symbols everytime. Wether I use hexadecimal or decimal codes, it only showes strange characters. I've looked at the hexidecimal code sheets for characters and text but the same applies, strange characters. And when I send a simple line of text to write like "sendserial(D15, 19200, "hi") the same applies, more strange characters.

So I'm lost, I can't find much other reading material or information regarding this display or its codes. Maybe I'm missing something or maybe this unit is faulty? If anyone could show me an example of how these codes should be used with the right context, I'd be very appreciative.




According to its manual, to turn the display off I should use the following syntax..

Hexdecimal: 0xFE 0x46 Decimal : 254 70 ASCII : 254 "F"

Can someone show me an example how to apply this syntax in code, or am I completly not making any sense?


hello. does it words now ? i'm intérested by your results. i' d like to send serial codes to my équipements by a vocal command. bye


Yeah, no. It's not working, no sense to it at all.

Its connected properly 5v, rx, Gnd, it and I am using right protocol Serial TTL and regardless of the baudrate i use, entering the codes described in manual and sendin them to the LCD as described in EZ-script, does not provide consistent nor desired results.

I have asked for pointers before but asside from your reply I have not received any others. So no, it's not working. I'm sorry.



Sounds like 19200 is not the default baud rate. Try different baud rates, like 9600


Hi DJ, thanks for your reply.

Well, the manual says its default baudrate is 19200. It also states that if i reset the lcd it will automaticly be usin 19200 baudrate. I have also tried usin 9600, the results do seem more consistent but they do not show the expected results as described in the manual.

When i try to send a display off command, it will show some strange symbol that i cant recognise regardless of the angle i'd look at it. If i send clear screen command, it will show a different strange symbol and if i use like text or characters, it will show a bunch of weird symbols.

In any case, i have not gotten any logical results. Now...the lcd board has 3 protocol jumpers that can be switched by desoldering zero ohm resistors from one protocol jumper, and soldering them back on a different protocol jumper.

User-inserted image

Its factory setting was put on I2C or 232 so I have tried switching that to TTl. But these smd resistors were so tiny and i did have a proper solder tip at the time and i lost the resistors. I resorted to just soldering them together without the resistors. Im sure this where my problem lies, it may not be sending or receiving clean signals this i right?


....anyway, i have no zero ohm resistors laying around. Is there a way to reproduce the same thing in some other way? what if i connect them using a tiny piece of copper wire, will that work?


United Kingdom

As far as I am aware a 0 ohm resistor is a piece of wire. If it needs 0 ohm then a jumper wire is sufficient.


Hello Rich, how are you?

Well, I have a feeling the LCD is now toast. I've soldered them with wires, I have even salvaged some 0 ohm resistors and soldered those on. Allthough the result are now definitly consistent, it only produces fully blacked out blocks on the display regardless of what i send to it so long as it is with 4800 or 9600 baud rate.

But it's okay. I've put this lcd thing asside sometime ago and I have no problem leaving it there. :P

Anyway, thanks for your replies.