I'm writing to a GLK19264-7T-1U device, and for some reason the the text isn't rendered properly.
These are the actions I do:
Send a "Clear Screen" command. (0xFE 0x58)
Write 20-chars-long text.
Waits 1 second.
Send a "Clear Screen" command. (0xFE 0x58)
Write 20-chars-long text.
Waits 3 seconds.
Send a "Clear Screen" command. (0xFE 0x58)
Write 20-chars-long text.
Doing the following for 3 times recursively:
Send a "Setting the Cursor Position" command. (0xFE 0x47)
Write 7-chars-long text.
The problem:
The text in action #8 isn't displayed at all.
Also, apparently that the text in action #5 doesn't get completely clear. I'm not sure since it doesn't make sense, because that the text in action #5 is located in another unrelated coordinate. It's better to assume that something else happens, which slightly corrupts the text that's sent in action #9 (It looks like that the "Clear Screen" command in action #7 doesn't completes.)
Note:
By "text" I mean ASCII characters, not commands.
Assume no delay, unless written.
Assume no other bugs/errors, unless written.
Commands are sent via UART (TTL) with an AT91SAM7X micro-controller (has an 18.432MHz oscillator).
UART communication speed is the LCD's default one.
In action #3: Instead of a 1 second delay, I tried a 2 seconds delay, and everything worked correctly by doing so.
My program/software is simple and I passed through the code to see if any errors exist.
I didn't find any bugs (although it doesn't confirms that my software is lack of bugs), so I wanted to be sure that it's not the LCD.
A question for conclusion:
How fast this LCD device can process commands and text?
I checked again and found that the following statement:
"Also, apparently that the text in action #5 doesn't get completely clear."
is actually true/correct.
I wonder, if you please tell me the font and font size you are using? Also in the FE 47 command (3 times) can you please tell me the parameters you send?
I made a simple script mimic'ing what you are trying to do, and I had to make up some parameters for the Goto command. It seems to work on my end. I used Lucida 10x15 font (the larger the font, the longer it will take to draw the glyphs).
Raquel Malinis
Design and Development
Matrix Orbital
The font I'm using is the default one: Small Filled. I assume it has a fixed font size (I couldn't find in the LCD's data sheet a command to modify the font's size).
In my first post I described the steps I did that caused the problem.
Those were just an estimation of the steps, so here are the exact steps (which different merely by the size of strings/text):
Send a "Clear Screen" command. (0xFE 0x58)
Writes 42 chars long text. (includes 1 newline character)
Waits 1 second.
Send a "Clear Screen" command. (0xFE 0x58)
Writes 48 chars long text. (includes 3 newline characters)
Waits 3 seconds.
Send a "Clear Screen" command. (0xFE 0x58)
Writes 32 chars long text. (includes 4 newline characters)
Doing the following for 3 times recursively:
Send a "Setting the Cursor Position" command. (0xFE 0x47)
Coordinates are set to: (84, 15), (84, 24), (84, 33)
When the first iteration sets the cursor to (84, 15) and last iteration to (84, 33)
Write 7-chars-long text. (no newlines)
As I wrote earlier:
The text in step #8 isn't displayed at all.
Also it seems that the "clear screen" command in step #7 doesn't complete, which as a result, makes a part of the text in step #5 to collide with the text in action #9.
Additional info:
Baud rate: The default - 19.2Kbps
Brightness is set to 128 (0xFE 0x99 128)
Contrast is set to 128 (0xFE 0x99 128)
All the three leds are off. (means all GPIO set to '1')
I am trying these things out on my end; but as a quick check, try and change the FE 47 with command FE 79 because I see you seem to be using parameters that are pixel x,y locations.
I will get back to you with what I find.
Update: I have tried the sequence out and it works. Can you please drop me an email at support@matrixorbital.ca ? I will send you the script file I used.
Raquel Malinis
Design and Development
Matrix Orbital
