lcd2041 rev 1.22 I2C

eric_l · Post by **eric_l** » Fri Jul 15, 2005 1:26 pm

Hi, are there any hardware modifications necessary to be able to use the I2C connector on the
revision 1.22 2041 display?

I'm trying to communicate with a Dallas Tini with the default jumper settings (J1 and J2 on), but
it doesn't look like it is working. The current pdf manual is perhaps a bit 'too new' (rev 1.5)

TIA, Eric

Tom · Post by **Tom** » Fri Jul 15, 2005 1:49 pm

Hi Eric,

You won't need to change anything for I2C communications on the revision 1.22 LCD2041.

Make sure you have the currect address. With J1 and J2 on the address is 5C. Make sure you have sufficient pullup resistors like at a value of 1K. You will also want a maximum of 100Kbs for the communication speed.

For more details you can look into the old manual at http://www.matrixorbital.ca/Manuals/LCD ... s/LCD2041/

For more information on interfacing with our units via I2C, you can go to the following link http://www.matrixorbital.ca/appnotes/I2C/

Let me know if you get the unit working.

Best Regards,

eric_l · Post by **eric_l** » Fri Jul 15, 2005 2:26 pm

Thanks for the quick reponse, I'll your suggestions.

Eric

eric_l · Post by **eric_l** » Sat Jul 16, 2005 3:03 pm

Pullup resistors are standard on the Tini board, but because the internal i2c routine probably respects the ACK,
I've written a bit-banging version. In both situations the I2C works properly with other I2C devices, but I can't
get it to work with the 2041.

I prefer to save the serial port from the tini and use I2C. If you've got any suggestions, I'll be happy to try..

Tom · Post by **Tom** » Mon Jul 18, 2005 9:43 am

Hi Eric,

Here is an excellent example of bit banging for I2C development.

http://www.lcdforums.com/forums/viewtop ... s&start=15

I hope this helps you out. Let me know how your development turns out.

Best Regards,