Matrix Orbital Corp

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:

1. Send a "Clear Screen" command. (0xFE 0x58)
2. Write 20-chars-long text.
3. Waits 1 second.
4. Send a "Clear Screen" command. (0xFE 0x58)
5. Write 20-chars-long text.
6. Waits 3 seconds.
7. Send a "Clear Screen" command. (0xFE 0x58)
8. Write 20-chars-long text.
9. 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?

Thank you.

Regards,
Dor.

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.

Hello Dor,

Thank you for posting on the forum.

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).

Hello Raquel,

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):

1. Send a "Clear Screen" command. (0xFE 0x58)
2. Writes 42 chars long text. (includes 1 newline character)
3. Waits 1 second.
4. Send a "Clear Screen" command. (0xFE 0x58)
5. Writes 48 chars long text. (includes 3 newline characters)
6. Waits 3 seconds.
7. Send a "Clear Screen" command. (0xFE 0x58)
8. Writes 32 chars long text. (includes 4 newline characters)
9. 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')

Hi Dor,

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.

Email sent.

Thank you.