[Lcdproc] Patch: MtxOrb adjustable backlight and display detection

Ethan Dicks ethan.dicks at gmail.com
Tue Mar 31 04:53:41 UTC 2009

On Tue, Mar 24, 2009 at 4:04 AM, Markus Dolze <bsdfan at nurfuerspam.de> wrote:
> Hi,
> I have questions on how the Display On / Off and Set Brightness commands of
> Matrix Orbital displays work:
>  1. If I use the 'Display Off' command, does it just turns the
>     backlight off like for older versions or does it completely turns
>     the display off?
>  2. If the display's backlight is off, what happens if I issue a 'Set
>     Brightness' command? Does the backlight stays off until a 'Display
>     On' command is issued or does the backlight automatically turns on?

Hi, Markus,

I've restored my dev environment to functionality and spent some time
tonight throwing some command strings at my LK204-7T-1U (the
recently-manufactured Matrix Orbital display with the built-in LEDs on
GPOs 1-6, the color backlight, and built-in keypad).  Here's what I

I send "display off", the display goes off *and* the backlight goes
off.  I had to send both a "backlight brightness" _and_ a "display on"
command to see chars again.  It does not matter which is sent first,
but both have to be sent.

When the backlight is off sending a "set brightness" does not turn the
backlight on right away.  It stays off until the "display on" is sent.

This is the only Matrix Orbital textual LCD I have (an "LKD").  My
other textual MO display is that VFD display that "doesn't like" the
newer LCD commands (but worked fine the last time I tested it as a
"VKD" type display).

I hope this is the sort of information you were looking for.  Let me
know if you need anything other sequences of commands sent.  Now that
I have my dev laptop back, it shouldn't take a week to get you an


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