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View Full Version : Big Problem in PBP To receive DMX



programmer07
- 3rd March 2007, 16:13
there is many example here but no one is working on dmx receive

still have problem and nobody knows how to receive dmx in pbp with "hserin" command.

I think it is impossible to receive in pbp maybe we can begin to learn assembly

I have PIC16f628A and i want to receive dmx from the "RX" pin of pic it is "RC7" and i need only to receive dmx signal no more.. some friends are saidm that i have to use "hserin" command for it but not any examples

keithdoxey
- 3rd March 2007, 18:10
I ask again but nobody nows.
this is my 3.th thread in this forum about the receive DMX.

OK, so I am going to ask a question now.

why do you have to ask essentially the same question so many times and in so many threads

Unless you expect someone to hand you a complete PBP program to do exactly what is needed, you will have to do quite a bit of the work yourself.

If you only ever COPY what has been written by others you will learn NOTHING.

This forum contains many threads and examples of using Hserin/Hserout, buffering the data and manipulating the data.

It also contains many examples of PWM to create your dimming which will also be needed in addition to receiving DMX.

As has been pointed out before, there is nothing magical about DMX, it is just very fast serial data but you do need to FULLY understand the capabilities of DMX and how it is intended to work. Again you have been given pointers as to where to find that information.

If you do not have much experience with PBP or with PICs in general then I would suggest that you build a few small projects to familiarise yourself with what can be done before attempting a larger project such as DMX decoding.

Irrespective of how many threads you start, no one is going to hand you the solution on a plate, YOU must undertake the bulk of the work yourself.

I am sure there are some people who would undertake you project for you if you provide them with sufficient reward so maybe that would be another option!

JEC
- 3rd March 2007, 18:28
Search the archives - more than a year ago I posted working snippets of code for receiving DMX using PBP. No assembly needed.

I've sucessfully used a 16F628 and a 16F88 at 20 and 16 MHz respectively. Transmitting and receiving data are equally easy and can be done in the background (using interrupts) if you're careful.

On a '628 at least, you can receive with a 4 MHz clock, but you won't have much time to process the data you've acquired. :)

As others have mentioned, there's more to the DMX signal than just the serial data. Make sure you understand how the break signal works and what duration it can be. An oscilloscope will make your journey much, much easier. Some of signal timing is pretty specific. Spent the $40 and buy a copy of the USITT standard. It's a great reference.

You need to become one with the USART chapter of your datasheet. You'll find charts which describe exactly which clock frequencies you need for stable reception.

Start by toggling an LED or flipping a pin when your code succesfully identifies the 'break' signal.

Then flip a pin when you've received and correctly interpreted the 'start' code.

Then grab data from the first channel and display it on an LCD or serial terminal. Make sure its value follows your console's fader position, etc.

Then try grabbing channel 10 or 96 or something arbitrary.

JEC

skimask
- 3rd March 2007, 22:22
there is many example here but no one is working on dmx receive

still have problem and nobody knows how to receive dmx in pbp with "hserin" command.

I think it is impossible to receive in pbp maybe we can begin to learn assembly

I have PIC16f628A and i want to receive dmx from the "RX" pin of pic it is "RC7" and i need only to receive dmx signal no more.. some friends are saidm that i have to use "hserin" command for it but not any examples

And yet AGAIN...I, along with many others will state the same thing...
Post YOUR code (not the code you've copied from other sites or even this site), post YOUR schematic (not the same schematic I found while looking for DMX info and the same one you posted in the other IDENTICAL thread)...and I'm 100% sure a few of us here in this forum will be more than happy to help you find errors and make it work to your satisfaction.

Until then...well, quite frankly...2 choice words come to mind...

Pic_User
- 4th March 2007, 04:28
I am beginning to miss Eng4444 ...

BigWumpus
- 4th March 2007, 18:49
I too !!!!