LK204-7T MEMORY UPLOAD

[poornendu]

My LK204-7T display was working correctly and I'd interfaced it to Arduino.

Now it is not responding properly and I'm not not able to pinpoint what caused the error.

I can only change the display brightness and contrast using uProject but cannot make anything to display on LCD.

It gives one character each when we press keys, but they are different from default "A, B, C, D ..." Instead I get 254 for three keys, 88 for two keys and 3 for other two keys.

Probably I've corrupted the default memory.

Can you please let me have the original memory file of the display and instructions on uploading it.

Thanks in advance.

[Clark]

Hello poornendu,

I understand some settings have been changed from default on your LK204-7T-1U, to temporarily restore defaults please use the manual override procedure outlined in your manual.

It is important that you are able to communicate correctly to the unit at the default 19200 baud rate before attempting to upload to EEPROM. Once all communication is successful in override mode, please use the correct file attached to Initialize Memory to factory defaults using uProject.

Thanks,
Troy

[poornendu]

Dear Troy,

Thanks a lot for prompt reply.
The LK204 is connected to Arduino via RS232 and Tx/Rx pins of Arduino are used to update the program.

I did manual override.

The present state is:
i) I can change display brightness and contrast
ii) I can change the state of three LEDs and keypad backlight
iii) User defined memory was overwrittern and now when I try to do the read things such as S No., it sends back characters from user memory.
iv) The characters corresponding to keypad keys were redefined by command and now I'm able to read correct characters using uProject.

The only issue is nothing is printed on the display. Neither bargraphs, large characers or plain text.

I believe that LK204 memory where it stores character map to interpret incoming characters to 5x7 display pixels has been erased?

Is the above understanding correct?

If yes, then what could have caused it, are their inbuilt commands by which character map is erased?

Further, what should I do to prevent this from happening in future.

[Clark]

Hi Poornendu,

Not a problem, I appreciate you putting the unit into override mode to confirm that you can still communicate with the controller.

To solve the remaining text display issue, in override mode after initializing the memory, you might try adjusting the contrast/backlight settings until the start screen is visible. Additionally, you might try sending the Set and Save Data Lock command to ensure the unit is unlocked using the Uploader tab and the Raw Data command found in the Other category. The command should appear as /254//203//245//160//0/.

Unfortunately, there is no way to modify the built-in character map via software, please try using the software suggestions above.

Thanks,
Troy