Corona

Hi PB,

Big thanks to yourself and all who have contributed.

I am requesting Corona protocol.

Uses CC2500 chip.

Will supply Module and rx.

TIA

Bm

edit: module and rx are around $30

Hi all,

Could someone please tell me how difficult this would be to do or learn to do.

TIA

Bm

I expect i know what the answer to previous question will be.

Next question.

How long would it take someone who does know what there doing but has no previous experience with Deviation?

Bm

FDR wrote: I don' fully understand what do you want to know...

I wanted to send PB module and rx to implement Corona in Deviation

FDR wrote: Do you want to implement the Corona protocol (the DSSS one I presume) in deviation?

Yes DSSS

FDR wrote: Do you have all/any the information about that protocol?

No, i have no idea where to find it or how to get it. I guess i would need a logic reader or something maybe. Again i have no idea.

FDR wrote: Do you really asking us, how much time it takes for you to learn to program deviation?

This was question in previous post, but i think this is not for me. however i do know someone who is very good programmer

FDR wrote: Look into the existing protocol implementations to get familiar with the task, and then you probably will ask more specific questions, which somebody can answer...

I can only roughly describe what PB has done when he has analyzed protocols:

What you need is a SPI logger which can snoop on the spi bus. You connect it between the original tx and the original rf module and log how they communicate.
This has to be done in all states - powering on (for initializing the rf chip), binding (pairing with the rx) and flying.
You will get a huge amount of information. This has to be analyzed.
The first what you need will be a datasheet for the rf chip where the commands are described. Knowing this you can separate the commands and the data.
For the data you have to find out how the rf packets are constructed - where are information about the used frequencies (if techniques like frequency hopping are used) and where are the channel data placed? What else is in the packets (model or transmitter ids, info about channel changing, ...)?
You have to determine in which period which data are sent.
This will cost two weeks, I would estimate.

If you are lucky somebody else has done this work before (e.g. for another project) and you get all these data well documented. This will reduce the overall time massively.

If you have all these information you can go and take one of the protocol C-script from deviation which is written for CC2500 (like skyartec, see FDR's link) and adapt it to the information found. I would expect this to be only a task of changing the data information and maybe fine adjusting the timing.
Afterwards you can build a new deviation version with this protocol included (needs a fully working development environment).
Then testing and debugging will follow.

I have never done anything like that but it sounds like a mixture of very much fun and still more annoying hard work. I personally would think that it could be done in two weeks (except data mining) if you can move straight forward (but I am known for my optimistic estimates...).

If I would start such a task I would make sure that I have a working cc2500-chip implemented in my tx to exclude difficulties with the hardware (and to have the original tx working if some information are missing).

Thanks very much, that explains a lot. At the same time a lot is over my head.

Just one thing for now. Corona do not make a tx only 2.4g module for Futaba and JR. I have Corona module fitted to Devo 8s at the moment via trainer port and works. Would i put logger between devo and module?

I think i will get friend to have a look and see what he thinks about helping me.

Bm

No, putting the logger between trainer port and module will not work.
They communicate with PPM signals, no serial protocol like SPI, and the packets are constructed in the module (the whole intelligence is inside the module). The PPM inputs only replace the sticks. In the module there must be a processor with its own firmware which takes the input signals and makes all the steps which I tried to describe above with initializing, binding and flying (what deviation would do in the corona-protocol-code).

EDIT: you could open the external module and place the logger between processor and rf chip as you would do with a complete transmitter.

Ok, got it.

Thanks again for your time.

Bm

module has plug in rf board, handy.

Bm

It does not look like as if the rf module is on a single board. I would guess that on the lower board there is only the voltage regulator while the processor and the rf parts are located on the upper.
Maybe I have been imprecise above: you don't have to put the logger between cpu and rf - it is sufficient when you can grab the signals of the lines (either at cpu or rf side or somewhere in between; no need to cut the lines).

There is 2 x ATMEGA48 on back side of large (lower) board.

I can make very nice pcb for smd and solder very very small smd components, this is not a problem for me.

Bm

Nothing on back side of small pcb.

CC2500 closest IC on small board>

Bm

If this works out i would only have to connect small board to devo?

Bm

This is a line from a thread in another forum, reffering to Corona:

"It actually behaves very much like Frsky, which, given the family connection, makes you wonder if they share design features, components & software."

I think they said they were a beta tester for Frsky

Bm

FDR wrote: Then there is a good chance, that it is a generic CC2500 module, and you can find the SPI lines go through the plug...

What are the other chips on the small board I wonder. One should be a power amp, but the others?

Will have a look.

Bm

Is this something like i would need to snoop bus?

www.hobbytronics.co.uk/bus-pirate

Bm

I have only litttle time actually but after a short look it seems to fit the needs.