Matrix Orbital Corp

Ok, I have the MX212 LCD display, the USB version with the keypad. I think its also called the LK-202-25-USB, or something like that.

Anyways, I'm having some really strange problems with it. They just started happening, and I have no idea how to fix them.

1) Display resets itself every time it gets unplugged. In order to see anything, I have to jumper keypad pins 6&7, plug in the LCD, remove the jumper, load LCDC, change brightness/contrast, and apply settings.
Once this is done, everything works fine, minus the keypad.

2) Keypad is unresponsive, and I get no confirmatin from any program for button presses. I've tried moving the keypad connector, but that doesn't seem to work.

I've added an LED to the TX and RX headers on the LCD. I get positive response when sending data from LCDC or another program, but I don't get anything when I press the keypad buttons, no matter what the orientation of the LED.

After reading through the documentation for the device, I'm thinking a command got sent to the LCD that somehow did a "adjust brightness and save". For the keypad, maybe "auto-repeat" command was sent.

I've been unable to find a program that will allow me to send any command listed in the documentation. I was hoping I could maybe send some commands to the device and fix those problems.

Any ideas on what I can do? The keypad problem really baffles me, but hopefully its just a command that is being activated and killing any other input.

Hello...

The fact that you need to manually override the unit everytime you power up to communicate, leads me to believe that you may have a faulty memory chip. The way it works is that for some reason if the baud rate gets changed you can manually override the unit and set it back to default 19200 baud. If the unit will not set the baud rate to 19200 after re-boot, which is saved in the memory chip, then there is a good chance that something other than software is the problem. One further check to support this conclusion would be for you to manually override the unit, once communicating, save a "dark" contrast setting and un-power the module. Now check to see if the start-up contrast is the value you previously set on power up. Let me know... As for the the keypad not functioning...you are obviously not getting values back from the LCD or your LED would be flashing to indicate communication...this could be a seperate problem ...

I've loaded up the LCD and tried adjusting the contrast in a couple of different programs: LCDC & Alphademo.

I can adjust the contrast in both, making the text appear really dark or really light. Once the unit is powered off, it still doesn't save those settings, and I have to do the manual overide again.

Is my memory chip faulty? If so, it is possible to get that replaced? Or would this require a whole new circuit? Are those available for purchase?

As for the keypad.... I can get the LED to flash, sort of. If I take a standard jumper and "jumper" pins 6&7, which are the last column pin, and first row pin, the LED will flash at a set interval. It will send a keycode that way, "F" I believe in LCDC.

From what you told me, there seems to be a problem with your memory chip...please email me at myero@matrixorbital.com and I'll look after it!

Miles wrote:From what you told me, there seems to be a problem with your memory chip...please email me at myero@matrixorbital.com and I'll look after it!

Sent you an email

Thanks...!!

A replacement LCD came in a few days ago, and works perfectly! Thanks a million for helping me out, I'm really happy with my purchase and the Matrix Orbital support!

Glad to be of service...Enjoy!!