Allegro Ethernet to DMX

[secanell]

LabRat,
I have purchase an Ethernet development kit from Microchip and a couple of Arduino boards that support spi and I2C.

Also have some NXP I2C to 16 channel (open collector 100 ma, 40v) type interface ... tssop32 type chip.

The thing is, I've come across the Allegro A6281 chip. Doesn't use an address, but can drive a cat 5 cable... though I don't think that will be needed.

I'm developing a board with the Allegro chip that can be configured to drive the cut-up (3 led to a cut) strip (cut up the 5 meter strip into 3 led sections), or to be able to add some resistors and the 5050 rgb led. The device can handle a clock rate up to 5 MHz, so moving the data into the device is not a problem, but one has to download the entire data stream before initiating the L1 load line. Basicly takes a 6 wire (+V (17V max), data, clk, load, output enable, grnd). The device buffers all lines to the next device.

Ok, with all that said... The ethernet device is configured to support 2 spi, 2 I2c, and a UART. I'll bring all of those out on a daughter board, but basicly I want to translate the DMX ethernet data stream into the spi stream for the Allegro devices.

I would treat each spi as a dmx address, but then I need to upload in the dmx stream say 3200 bits for 100 nodes which is 400 bytes of data. I will have the ethernet pic initialize the string before getting started, such as a color correction profile based on a color meter for each color. The profile will get stored into the ethernet dev kit.

My question to you.... will I be able to upload a large data stream with with an end command, such as 32 bit of 0.

Then second, can I turn the DMX into an I2C address with data.
All of this executed under Vixen!

Thanks
Steve

[LabRat]

Sorry... you lost me on this (I've tried parsing it several times, and I'm not clear on what you are trying to do).

The interface to the Allegro appears to be a custom serial protocol (I only glanced at the data sheet), and you would have to bit-bang the interface from your arduino (it doesn't appear to be either I2C or SPI). Are you saying that you want to write something that would accept the ArtNet packet (ethernet wrapped DMX data), and conver that into the custom serial (bit banged output) required by the Allegro chip?

To make matters more complicated, keep in mind that my effort was the glue logic between Vixen and the ArtNet library. I didn't have to actually create the packets themselves. That was handled by the library. So I'm not going to be much use to you. There are descriptions of the ArtNet protocol "out there" (I came across them somewhere), and they will tell you what the format of the packet is, as well as any responses that you need to make etc.

As to your second question - Can you turn DMX into an I2C address with data
That is all up to you, but I don't see that it would be under "vixen". What you appear to be proposing is a mechanism that would take the DMX universe (or a small part of it), and convert it into a series of I2C write commands, in order to update *something out on the i2c bus*. It would be fairly trivial to map the DMX address, to the i2c device address, and update the device accordingly. I would recommend that you maintain a local buffer of the values expected in the device, so that you only send i2c updates when the values change. But that's all up to you and how much RAM you've got available for your development.

Hope this helps... though I somehow doubt it will. :)

[DynamoBen]

secanell, I'm trying to figure out what this has to do with this thread. Is this artnet plugin related or a general hardware design question?

[Entropy]

secanell, I'm trying to figure out what this has to do with this thread. Is this artnet plugin related or a general hardware design question?

I agree. Looks like what he's trying to do is pretty similar to the thread here - http://doityourselfchristmas.com/forums/showthread.php?13706-DMX-to-PCA9635-bridge-using-an-Atmel-AVR (Yes, one of my old projects which I REALLY need to put some finishing touches on.)

Except he wants DMX-over-Ethernet input instead of just straight DMX.

[DynamoBen]

I agree. Looks like what he's trying to do is pretty similar to the thread here - http://doityourselfchristmas.com/forums/showthread.php?13706-DMX-to-PCA9635-bridge-using-an-Atmel-AVR (Yes, one of my old projects which I REALLY need to put some finishing touches on.)

Except he wants DMX-over-Ethernet input instead of just straight DMX.

I moved this to its own thread, under the DMX portion of the forum.