PXX work

[MikeB]

Go here viewtopic.php?f=5&t=387#p4041
and download the zip file.
You don't (currently) need to update the receiver. You need to use the er9x.frk file, from the .zip, to update a DJT. Remember this is a test version, although you can always update back to a standard release version anyway.
Once updated, the DJT will 'talk' in either PPM or PXX, but will only bind to a telemetry receiver. To use PXX, you will need to install r732, or later when it exists, of er9x.

Mike.

[Clivew]

Thanks Mike, it works!

[MikeB]

For general information, I found my 'standard' USB to serial adapter could not be used to update either the DJT or the D8R-II. The FrSky upgrade lite uses the Silicon Systems CP2102 chip, which may well accept higher baudrates than a 'standard' adapter, or the FrSky update program is looking specifically for the 2102 chip. I'm 'lucky' enough to have a Silicon Systems dev. kit for the CP2102 (obtained for work reasons), so I was able to simply use that as a USB to serial adapter. I still needed to keep the wires, between the output from this and the inputs to the module or rx, short or even this didn't work. I was using my 1 metre (3 feet) long ribbon cable extension for 9-way D-types, which is why I reckon the baudrate being used is high.

Mike.

[MGeo]

What are you finding the adavantages or disadvantages are for PXX pulse width based protocol vs the serial DSM2 protocol? It would seem that a serial protocol like DSM2 that can use UART hardware support would be less processor intensive?

[erazz]

I posted the roms in this thread.

I would still caution against using this ROM for flying models. I have a feeling it still needs more testing.

[MikeB]

As we don't have a 'spare' serial port, both the PXX and DSM are processor intensive while sending their data. One of the reasons for the ersky9x board is to provide hardware support for such protocols. We have a synchronous serial port on the relevant pin, with DMA to supply the data, so the processor will have nearly nothing to do while sending the data.

Mike.

[jhsa]

don't we have enough extra pins to put them ?? plus the audio mod??

[erazz]

It's not a problem of pins but rather a problem of on -chip "devices". To really do it properly you need either a DMA (direct memory access) device or another serial port. Currently our only serial port is used for telemetry and there are no DMA devices on the chip.

[jhsa]

ok, understand now.. thanks.

[Clivew]

Not sure whether this helps or not, but I've been trying all the versions of standard frsky roms.
I found the only pair that give failsafe from the transmitter are these ones:-
Module- V2_host_romb_build-100826.frk and the receiver- V2.fdd_rx_build_100826.frk
There is a downside however.. If you press the button too long, it sets the receiver to
high speed mode, not good if you have analogue servos!

[erazz]

Yeah, I've written them again to hear what they are working on.

I want to get the 16 channels, the FS and the Model match to work!

[Clivew]

Yeah, I've written them again to hear what they are working on.

I want to get the 16 channels, the FS and the Model match to work!

Good to see you're on the case, I guess without those features PXX has no advantage

yet perhaps. Or have I missed something? (Most likely!)

Keep up the good work!

[erazz]

OK guys,

I've gotten a response from Eva.

16 channels, Failsafe and Model Match all need to be addressed in the receiver FW. They want us to make sure the Tx FW is working properly so they can start work on the rx FW.
You can flash the FW to the tx and use it for both PXX and PPM without problem. If you have a system that you can spare, try to do this and give us some feedback. The more testing we do the better the final system will be.

I have been using the FW in my module for the past couple of days with both PPM and PXX. I haven't noticed any glitches or problems. This makes me more confident.

[jhsa]

wouldn't we need 2 receivers for thr 16 channels? or for that would we have to use PPM Sum?

[Rob Thomson]

I have had it running.. only noticed one issue.

When I turn on my model.. in PXX mode.... the servo's initially all jump about as the TX & TX get lock.

I have only seen this on my gliders - so not sure how much issue this may be if used on an electric model?

But other than that - no problems!

[shaddi]

wouldn't we need 2 receivers for thr 16 channels? or for that would we have to use PPM Sum?

PPM-Sum on the new D4FR-II with 16 Channels would be awesome. Killer for all those Multirotor-flyers, like me

[MikeB]

For 'real' testing it would be hlepful if the PXX tx module also worked with PXX in, and the switches set to use a non-telemetry receiver. I have several indoor models I would actually try flying indoors using PXX, but none of them have telemetry receivers, and I only have 8 channel telemetry ones which are a bit big for them.

Mike.

[Kilrah]

16 channels, Failsafe and Model Match all need to be addressed in the receiver FW. They want us to make sure the Tx FW is working properly so they can start work on the rx FW.

Do you know at this point how the 16 channel mode will work?

A few ideas:
2x 8-channel receivers, the main one is used normally, gets telemetry and serial downlink and outputs channel 1-8, while the second one (selected for example by putting a jumper over the TX and RX serial pins, as they will be unused anyway) outputs 9-16
CPPM-enabled receivers (they should all be able to do that BTW, not only the 4 channel and a special version of the 8 channel, why not use a jumper on the normal 6 and 8-channel like is done on the D4FR?) have a choice of outputting either a single, slow-refreshing PPM stream as it will be long, 2 separate PPMs for 1-8 and 9-16, or raw PXX (that could then be implemented by the various multicopter,OSD,... manufacturers)

[cre8tiveleo]

De ja vu...

Check out the 11th post and on.

Sounds the same...

---
I am here: http://tapatalk.com/map.php?b0zigz

[Kilrah]

Nope, because the earlier discussion was using 2 separate TX modules, each bound to a different receiver, that basically had nothing to do with each other. They just send the 2 different 8-channel PPM streams the 9X is giving.

The only thing I found regarding the single TX module PXX-based 16 channel solution is this:

And how could we have the 16 channels? 2 receivers?

Working on that

[jhsa]

well it looks like I've repeated myself, repeated myself, repeated myself, repeated myself, repeated myself, repeated myself,...

[cre8tiveleo]

Yawn... Stretch, whut?

[mgros]

I have had it running.. only noticed one issue.

When I turn on my model.. in PXX mode.... the servo's initially all jump about as the TX & TX get lock.

I have only seen this on my gliders - so not sure how much issue this may be if used on an electric model?

But other than that - no problems!

I have noticed The same.

[Clivew]

As far as I can see, there is no difference at all in performance switching between
PXX and PPM with my servos at least. As Mike said it's a pity they didn't make the
non telemetry option with this firmware, but I guess it shouldn't be too
hard for them to implement it?
Apart from that, PXX seems perfectly fine to me!

[Clivew]

I have an idea for Erazz Mike and Pat.

How do you fancy a short break in Jiangsu?

I reckon you could sort it in a couple of hours between you

[cre8tiveleo]

Coastline of the Yellow sea! Very Beautiful there!

[erazz]

FrSky seem to like the idea of having a stream sent from the tx to one pin of the rx..... This'll be interesting!

[android78]

FrSky seem to like the idea of having a stream sent from the tx to one pin of the rx..... This'll be interesting!

It's an interesting idea. If you can have each servo select its own channel from the stream then you can simplify wiring as you just have the receiver and a bus coming from it. I've seen this done in toy robot servos and wondered if it would come to RC... It'll take some time, but seems like the direction it's going.

[pmackenzie]

Futaba already does that - it is called SBus.

http://www.futaba-rc.com/sbus/index.html

[jhsa]

Yeah but I think it'll increase the number of crashes and the weight on the models..
With the s-bus system, if one of the buses fail, you don't lose only one servo. you can lose an entire wing or both halves of the elevator for example.. and I don't think there is redundancy in the system..
And on big models the extra weight might not be a problem but in gliders for example.....
I've read before that frsky is making their own s-bus system which is if I'm not mistaken compatible with Futaba.. that's why they like the idea. cos they're doin it