marlin firmware and half height prints

[printbus]

I think there was code posted... But one of our members here knows all about the LCD Panel corruption and how to work around it. If you search for i^2c you will find where I got corrected on how the panels work and the code (and explanation) that you want.

Roxy - I could have elaborated, but I was wondering about the changes specific to the half-height problem. As to the display issue, the OP is trying to add a graphic display panel onto his printer, not one of the usual 20 characters by 4 rows jobs. I have no idea whether the graphic panels use the same nibble interface that the character displays do, but I'm guessing the interface could be quite different. I'm actually the one who explained the character corruption issue we can get on the 20x4 displays, but it's not related to the OP's display issue. FWIW, the thread where I discuss the 20x4 screen corruption problem is in the firmware enhancements to marlin area - http://3dprintboard.com/showthread.p...ed-LCD-screens

FOLLOWUP COMMENT: The pixel mapped graphic display modules don't have the nibble transfer mode, so the nibble-sync issue that leads to corrupted text on the 20x4 LCD modules shouldn't be possible. Marlin communicates with the graphic module using Serial Peripheral Interface (SPI), like it does with the SD card.

[Roxy]

Roxy - I could have elaborated, but I was wondering about the changes specific to the half-height problem. As to the display issue, the OP is trying to add a graphic display panel onto his printer, not one of the usual 20 characters by 4 rows jobs. I have no idea whether the graphic panels use the same nibble interface that the character displays do, but I'm guessing the interface could be quite different. I'm actually the one who explained the character corruption issue we can get on the 20x4 displays, but it's not related to the OP's display issue. FWIW, the thread where I discuss the 20x4 screen corruption problem is in the firmware enhancements to marlin area - http://3dprintboard.com/showthread.p...ed-LCD-screens

OK! Sorry to interrupt! Thank You for the explanation!

[printbus]

It irks me when manufacturers and retailers don't provide sufficient reference information for their products, or worse yet, when the information they provide is incomplete or outright wrong.

Makergeeks provides two sets of instructions on how to enable the graphic module support in Marlin - printed text on the product page and the "how to hook up..." video on the product page. IMO, the text guidance on the product page is outright wrong, even ignoring the typos and errors that are waiting to surprise the non-programmer. The text appears to be the changes necessary to add a typical 20 x 4 character smart panel, not the graphic bitmap style. The firmware change instructions in the video are likely what you need, but I think there's one important problem in what the video says. It talks about how if the configuration.h file in your Marlin source doesn't have a commented #define REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER that you can uncomment, you should just add the #define statement for it. Huh? That might work, but only if the rest of the code is already there to react to that #define. I would say that if your configuration.h file doesn't have that commented line waiting for you, you need to look into whether the Marlin version you have has the graphic panel support there. As a minimum, I'd search the Marlin files to see if they already contain the REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER text anywhere. If not, you need to find a newer version of Marlin to be working with, since just adding the #define for a new display type won't get you diddly squat.