SPI Controller...has anyone use this before?

newaisa

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kool-lites

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newaisa said:
Hi,


I was looking for some PWM DC Controller and came across this. It works on both DMX and SPI interface.


http://ltech.en.alibaba.com/product/447836245-209539754/LED_RGB_pixel_driver_LT_280_24_DMX_channel.html

I am planning to use my arduino UNO to act as SPI master. Will it work? I can't find any information on it whatsoever on the clock rate, IC they use and etc.


If anyone knows or have used this before, please do let me know. :)


JY
YES.
SPI id used to communicate with a number of "controllers" I call them Serial SSRs. The Grinch is an example that uses the SPI.
The Olsen 595 is another example.
I use SPI to drive the 595s on my own controllers, like my 8 Channel RGB LED Flexible Strip Controller
It is easily implemented with an arduino, but but last time I checked you are limited to about 24 channels. if you write the progam in ASM, and change the crystal to 20Mhz, 64 channels is possible. RPM's Grinch Dimmer is an example.
 

kool-lites

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Most of the controllers I mentioned above use software PWM to achieve dimming

Another thing to consider is most pixel use the SPI to communicate with the pixels. In this case no PWM is required as the pixels have the dimming function built in.
 

newaisa

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kool-lites said:
Most of the controllers I mentioned above use software PWM to achieve dimming

Another thing to consider is most pixel use the SPI to communicate with the pixels. In this case no PWM is required as the pixels have the dimming function built in.

Hi thanks for the reply.
One thing I am not too clear is about the SPI sequence for this controller. I know SPI signal will work, but how do I figure out what is the sequence I need to send to get it started? Which few bits addresses the channel and which few bits addresses the pixel effect? Tried asking the seller but he doesn't have any clue on this so I might try asking here.


Let's say I want all channels to have PWM of 50% duty cycle. What are the bits I need?


I hope you would know what I'm trying to ask here. Can't think of any better sentence to go about. :-[
 

newaisa

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dmoore said:
What is it you are using this DMX controller for?

This controller will accept both SPI and DMX according to the specification. But I will try to go with SPI path since I have some experience with SPI but none with DMX.


I will be controlling a lot of 5V LED. Each channel will handle up to hundred of LED. The effect will be few groups of light with independent effects. Btw, all of them will be single color. So I only need On/Off/Dimming on each channel.
But still trying to figure out the control library of this thing. Like the question I posted above.


If anyone know please enlighten me. :)
 

random

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newaisa said:
One thing I am not too clear is about the SPI sequence for this controller. I know SPI signal will work, but how do I figure out what is the sequence I need to send to get it started? Which few bits addresses the channel and which few bits addresses the pixel effect? Tried asking the seller but he doesn't have any clue on this so I might try asking here.

If it speaks SPI they must supply you with a datasheet. The datasheet tells you operating parameters, interfaces and protocols. They should give you this before purchasing so you can see if it's suitable for your use. If you can't get a datasheet from the seller then don't buy it. If he doesn't know what's in it then you have even less chance!
 
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