LK162-12-WB prints gibberish/adds characters

LK/ELK/VK/PK/OK/MX/GLK/EGLK/GVK/GLT Series

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Jim
LCD?
Posts: 1
Joined: Wed Aug 15, 2012 8:01 am

LK162-12-WB prints gibberish/adds characters

Post by Jim »

I am using Matrix Orbital LK162-12-WB Serial# 12M03-3927 purchased from DigiKey.

First you should know that the datasheet that is linked to the digikey product listing has the wrong I2C address listed for this part. The datasheet they link to is titled as a Technical Manual revision 4.0. It lists the I2C address as 0x80.

The datasheet that appears to have the correct address is titled as a User Manual Rev 4. It lists the I2C address as 0x50.

It is unclear which of these manuals has the correct or full set of commands.

The issue I am having is that my display consistently prints additional characters and gibberish. For example the "Clear Screen" command is listed in the User Manual as 0xFE 0x58; the desrciption says that it should clear the screen and place the cursor at the top left position. It does this maybe 25% of the time. The other 75% of the time it simply prints gibberish on the display.

Other commands behave similarly....approximately 25% of the time the correct action occurs and the rest of the time the display prints 2 or 3 characters of gibberish. Commands from the Techinal Manual also exhibit this behavior.

I have a logic analyzer and an oscilloscope with serial decoding features for I2C. The I2C bus has the correct data. The start condition occurs correctly. The address occurs correctly. The display responds properly with the ACK. The message bytes are properly transmitted with corresponding ACK. I can find nothing wrong with the bus signal levels and there are no additional or unaccounted for signals or bounces that might be interpreted as data.

I have spent a few hours troubleshooting this. I believe the issue is in the display.

Raquel
Matrix Orbital
Matrix Orbital
Posts: 796
Joined: Thu Aug 19, 2004 3:37 pm
Location: MO Office

Re: LK162-12-WB prints gibberish/adds characters

Post by Raquel »

Hi Jim,

Thank you for posting on the forum.

The Technical Manual Rev 4.0 linked in Digikey mentions 80 as slave address. This means 80 decimal, ie 0x50 (not 0x80).
As we are already in contact via our ticket system, I will reply to your enquiries there.

Thank you and Best Regards,
Raquel Malinis
Raquel Malinis
Design and Development
Matrix Orbital

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