Your favorite LCD for RAMPS
February 04, 2014 04:27PM
I’m considering a new RepRap build and think I want to add an LCD/SD card reader this time. I used a Printrboard before, but nowadays it looks like RAMPS can be had for a bit less.

So for LCDs with RAMPS, there seem to be a few different options:

Cheapest is the ‘Smart 2004’ text-only:
[www.ebay.com]
[reprap.org]

For 13 bucks more I can get the ‘Smart controller 12864’ graphical display:
[www.ebay.com]
[reprap.org]

And there are other options out there, like the ‘Panelolu’:
[www.ebay.com]
[reprap.org]

Does the graphic display offer any advantages besides pretty pictures? Do you have a favorite LCD? If so, what makes it best?

-Matt
Re: Your favorite LCD for RAMPS
February 04, 2014 05:29PM
If you're aiming to push the boundaries of speed or you're looking at a Delta (which tends to require a bit more CPU), then it might be best to stay away from the graphics model. IMO the graphics "should" take more code to draw (does depend on how the drawing is done, but it's also got more info on screen, which means more to update).

Note that this is not meant to be a definitive statement, it's just a somewhat informed opinion: If someone can show that the graphics LCD requires less CPU to drive, then go for it.

PS: I don't have any boards with a graphical LCD setup, so I'm going on what I know of electronics, rather than on a definitive use case.
Re: Your favorite LCD for RAMPS
February 04, 2014 06:58PM
> ...IMO the graphics "should" take more code to draw ...

I am considering a delta.

I took a quick look at the Marlin code. They do use a graphics library and are a bit busier when configured for a graphic-display, but it looks like the refresh happens no more than 10 times a second in either case. I'm guessing we could reduce the refresh rate if it was too much overhead.

But my gut says it's unlikely to be an issue, since the stepper driving code is interrupt driven.

Anyone ever heard of any computing speed/capacity issue like this with Marlin?

-Matt
Re: Your favorite LCD for RAMPS
February 04, 2014 07:55PM
There is a thread on this site from the time that the graphic LCD (12864) was being added to Repetier firmware, and it discusses the performance issues. I believe that they ultimately decided to leave all of the animations off, because the 16Mhz processors were wasting too many CPU cycles with graphics. Feel free to search for the thread.....
Re: Your favorite LCD for RAMPS
February 04, 2014 09:11PM
Thanks. I couldn't find the thread, so if you can I'd be curious to read it.

But anyway, performance is really tangential to my original question, namely: Is there any practical advantage? Does the graphic version (or any other LCD variant out there) give me any more information than the cheap 4 x 20 LCD?

-Matt
Re: Your favorite LCD for RAMPS
February 05, 2014 05:37AM
Here are two threads discussing the CPU impact:

http://forums.reprap.org/read.php?267,240739,282856#msg-282856

http://forums.reprap.org/read.php?267,287460,294457#msg-294457

There is also a picture of Repetier's GLCD main screen in the first thread, which may help you to decide whether the two extra text lines on the GLCD are worth the performance hit. Marlin uses a completely different layout.....
Re: Your favorite LCD for RAMPS
February 05, 2014 07:13PM
> Here are two threads discussing the CPU impact ...

Good reads. Thanks.

I think I'm probably sticking with the cheap text display, simply because I can't find any compelling reason to 'upgrade.'

I'm still hoping to hear from anyone with experience of both, so if that's you, please respond. I'll continue to monitor this thread.

-Matt
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