View Full Version : Mini LCD A/V Color Display

05-20-2010, 10:03 PM
In the store section, the Mini LCD shows that it is a 7" (inch)
and included in the Propeller access. kit.

And in the kit, they say it's a 3.5 "(inc.)

Which is it?
And at the same time, how many of these little beautifull gems can I plug with the Prop?


(Very tempted to move to the prop from BS2) But still have lots of noob questions with the language and limitations with memory size ...which I really don't understand ...

Bob Lawrence (VE1RLL)
05-20-2010, 10:33 PM
It should be 7" for both.

A few years ago they were 2.5" and then 3.5". It looks like it's been upgraded again.

If you click on the LCD item in the kit "items" It will take you to the 7"LCD description. The kit info just needs to be updated.

Mike Green
05-20-2010, 10:34 PM
The original Mini-LCD A/V display was 3.5". Parallax apparently had problems with the supply of this particular device after a time and switched to a different supplier and device with a larger screen.

Each cog can independently produce a video signal, so theoretically you could attach 7 displays to a single Prop leaving one cog for a "main" program. In practice, it depends on what you want to display since each display requires a buffer. If the display is text-only, you could keep the buffer in the cog's local memory. If you want graphics, you will need some buffer space in the shared hub memory and that might be the limiting factor.

05-20-2010, 10:47 PM

Great 7" display.. perfect.

So I imagine, 2 of them with maximum graphics· would be on the safe zone? or maybe 3?



Mike Green
05-20-2010, 10:54 PM
You can figure it out. What do you want for resolution? What kind of pixel depth (bits per pixel) do you want? How big a display buffer does that need? Do you want double buffering to minimize flicker? How big is your program (the display buffers and program have to share memory)?

05-20-2010, 11:11 PM
Well I can't figure it out, since I don't know any of these things, and what is the maximum size, and the details...
I'll stick with my BS2 and my PC.· No calculations needed. Not much limiting factors..just the BS2PX.

I just program and as long as I don't get an error, I just keep on adding...

And most of the work is done with VB2008, so I don't worry about unknown calculations and buffer this and that...

Well it was worth a try...


05-21-2010, 02:53 AM
What sorts of things were you thinking of displaying? A 256 x 192 pixel 4-color image (like the Propeller graphics demo uses) takes up 12k, so there's room for two buffers. So yes, you could have two separate displays. If you can get by with lower resolution, you might be able to have three or more. I'd kinda like to see that, actually.

One possible drawback to the 7" display is the non-4:3 aspect ratio, so circles will appear squashed.

05-21-2010, 05:01 AM
I was hoping to use the maximum 480 x 240 .
To draw a COMPASS, a tilt angle like and airplane attitude angle. Some progress bar and the rest is numbers that fits in a Box .
Like a predraw image and I just populate it: Speed , RPM, Temp engine, etc.., and some temp sensors outside ,inside , cargo etc...
I read a GPS numbers to give me my Altitude and put that number in the compass section.

I can re-download a picture from my ACER Notebook, that will show you what is the intent.

I was hoping to maybe split all the info into 2 screen.

Trying to built a space shuttle http://forums.parallax.com/images/smilies/wink.gif
Edit: Here is the first picture I took. It has been modified a lot since, but the idea is there.
The 2 long white lines is for debugging only.

Post Edited (Yoshti) : 5/20/2010 10:10:18 PM GMT