Connecting WS2801 to teensy

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Deamon

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Hi,
I have already tried connecting teensy to 3000 ws2812b leds and it looks magnificent.
Now since those are too bright i want to try the same with ws2801. All I want to know is how can I connect all those leds to a single teensy as i did before.
I know that ws2801 needs two signals as data and clock i.e. din and sck.
How can I get both from only din?

Few days back I saw a module that converts din signal into two separate din and sck. But now I can't find the same link.:confused:
Is there anything similar available?

Please Help.
 
why would you need that ? The teensy can control the ws2801 using the SPI port, you should check the FastLED library to do that.
 
Deamon said:
I know that ws2801 needs two signals as data and clock i.e. din and sck.
How can I get both from only din?
Click to expand...

SCK is available on pin 13.

Few days back I saw a module that converts din signal into two separate din and sck. But now I can't find the same link.:confused:
Click to expand...

I do not understand how any module could recreate SCK from only the data signal (DOUT, pin 11 on Teensy 3.1). The SPI protocol simply does not have any way to recover the clock from only the data signal.

Perhaps that module used some other protocol?
 
Hi guys,
First extremely thank you for your replies.

nlecaude said:
The teensy can control the ws2801 using the SPI port, you should check the FastLED library to do that.
Click to expand...

Yes I already saw that. But my problem is I want to make it exactly like WS2812b i.e. using eight strips and not a single one rotated. This is because if you add more than 500 leds in series, you can see the delay between first and last led getting bright. So if I connect 3000 leds in series, my effects (There are some effects that I designed with Processing) would look really really ugly.

how any module could recreate SCK from only the data signal
Click to expand...

To be true, I don't exactly remember. At that point I didn't thought of it as any importance. I don't even remember what exactly I saw.

So please help me. I feel like I can't move any further with this project.
 
Are you sure there is a delay with ws2801 ? That is true for ws2811 because the protocol relies on timing but might not be true for ws2801.
And if you find the ws2811 too bright, why not dim the whole array ?
 
The WS2801 and the WS2811 are going to be running at different data rates, 1Mhz vs. 800khz. If you want to connect 3000 leds in series and get decent framerates out of it, used the LPD8806 which the teensy 3 can drive at somewhere around 20Mhz.
 
Well,
I seriously don't know, weather it would show the delay after 500 or 3000 leds. The problem is the initialization clock rate is not mentioned in its datasheet or the sample code given at

https://www.pjrc.com/teensy/td_libs_FastSPI_LED.html

And if you find the ws2811 too bright, why not dim the whole array ?
Click to expand...

I already tried implementing it. I think it doesn't give me that "!!WOW!!":cool: effect. Now I want to try with WS2801 similar to

http://www.vozop.com/index.php/ws2801-chip-12v-led-rgb-digital-point-modules-round-3-leds-2801-ic.html

I am not going to buy them from that website. But the similar ones. to create something like
Lpd_6803_IC_Flash_Wall_Lighting.jpg
 
dgarcia42 said:
I have documented the information I have (and others have tracked down) about clock speeds, pwm rates, and dark power draws on the FastLED documentation wiki here - https://github.com/FastLED/FastLED/wiki/Chipset-reference
Click to expand...

Thanks that was extremely helpful.

So here are some of my calculations. Please tell me if I am wrong.

Clock rate = 1MHz;

Total data that can be sent in 1 second = (clock rate)/8 = (1MHz)/8 = 125000 Bytes;

Minimum refresh rate (For my perticular design) = 30Hz;

Total data for a single frame = (125000 Bytes)/30 = 4166 Bytes;

Bytes per led = 3 Bytes;

So max no. of leds that support 30Hz fresh rate = (4166 Bytes) / 3 = 1388 leds.

So this means for my particular design I can connect maximum of 1388 leds to a single Teensy 3.1.
 
That's assuming you are spending 100% of your time pushing bits (I haven't gotten to doing a DmA SPI implementation on the teensy yet).

The lpd8806 is really the best option out there for a long chain of LEDs where splitting up the lines to use something like octows2811 isn't doable for some reason.

(Personally, I can't wait until the ws2801 dies in a fire)
 
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