Just note to help anyone trying to find out if a RepRap Discount Full Graphic LCD ( [reprap.org] ) can definitely be used on a Melzi 2.0 running Marlin.

I had success today using a DIY adapter board found here on Thingiverse and credit should go to Dave for posting up his work there.
[www.thingiverse.com]

For whatever reason the information was hard to come by about any possible compatibility between this display and Melzi boards, in fact some sites or vendors say it's not compatible.
Doubts come about I think because the Melzi has less I/O lines extended to the external header sockets than RAMPS or Sanguinololu.

My display is actually a clone made by Geeetech, bought from Ebay for $15.

One comment of note is that the complied code with graphic LCD support was much larger than without and won't fit on the Atmega644 chip on original Melzi's, in fact it only fit on my Atmega1284P after I recommented out one of the SD card functions to save a few bytes.

Hope somebody finds this useful and saves some time for them.
Martin


Edited 1 time(s). Last edit at 03/05/2015 06:01AM by mr.sneezy.

Would this adapter work?

Quote
hsbontop
Would this adapter work?

The Sanguinololu header has four extra pins that the Melzi doesn't. Two are just 12V power and ground, but IIRC two are data lines. It might work though IF those two lines are not used in this case. Need a schematic or a much better image showing the tracks.
Or just buy one and try it, the extra four header contacts will just sit there unconnected.

I just updated the firmware on the Melzi 2.0 to Marlin 1.0.3 Dev.
With this version there is no need to disable any functions to save code space.
With the Reprap Discount Full Graphic LCD option enabled and the SD card stuff enabled the file size was well under 128k at about 119K.

Martin

hello, friend!
i have some issue with the similar lcd, here is the pic and a link to my firmware what would you suggest? thank you.

That looks like the data between the Melzi and the LCD is being corrupted and you are getting pixels displayed in the wrong positions.
Does it look the same (I mean really identical) every time you start the machine, or does the corruption vary ?

Martin

Hi, is it possible for you to provide me with the modified Marlin fw that would allow me to power a RepRap Full Graphic Display with my Melzi board? Thanks.