Beginner Questions - Pixels

[JonB256]

I'll try to explain this simply but accurately..   None of the strings actually have any concept about where they are located in a string.  Technically, every pixel actually "thinks" its first in the string.  An example will make this simple for you to understand.

Lets say we have a string of 5 pixels;  the controller will send out data on the wire than looks like this;

A B C D E

The first pixel in the chain looks at that and says, " i'm pixel 1 ", and uses the first data in the string.. In this case A.   It then does its other job, it resends that data, but without the "A" data..  So, it retransmits the data like this;

B C D E

The seond pixels in the chain ( although it does'nt know its second says " im pixels 1, and uses the first data in the string, which is now B.      It then does it other, resending the data but dropping the "B" data.. so it send outs

C D E.

The system repeats it self until the last pixel who will only receive one bit of data... and it will have nothing to send out.

MPH, that makes perfect sense - but it makes me wonder how the TP3244 and pixel strings do Grouping?

Also, when people put a pixel close to the TP3244 because of a long wire run to the first display pixel, are you just giving up a pixel or is there some way to make it just pass along the data without taking off its data?

JonB

[chrisl1976]

Also, when people put a pixel close to the TP3244 because of a long wire run to the first display pixel, are you just giving up a pixel or is there some way to make it just pass along the data without taking off its data?

JonB

This problem is only present in the first batch of TP3244's as far as I know. I assume the next batch will not have the distance issue. 

[Tabor]

Grouping is very simple, you just specify how many pixels get grouped together "n" and the controller just sends the same data "n" times.
So if you had dmx data of:
0xFF, 0x0F, 0xF0
and a grouping of two, the pixel data would look like:
0xFF, 0xFF, 0x0F, 0x0F, 0xF0, 0xF0.
This is not exactly how it works for RGB, but should give the idea.

By using a pixel to extend the range to the string, you effectively giving up a pixel, but if the controller program is written correctly dummy data can just be sent to the first pixel as it will be stripped out of the stream and you will not loose 3 channels.
So you are using one hardware pixel, but should not effect you channel count output.

[JohnBullard]

Opps, wrong section, sorry