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Old Feb 25, 2010, 05:08 AM
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Originally Posted by phil_g View Post
Jonathan/Chase, I've been studying the protocol document, please could you confirm if the 4800bps RS232 channel has to be framed using the "10 byte plus header" protocol?
I'm not sure because parts of the dicumentation imply that it is a free flowing, no protocol, continuous serial stream... but other parts imply that it must be framed. If framing is necessary then I have some conversions to do.
Many thanks
Phil
The serial port of the receiver(also called REMOTE), it is "NOT" 10 bytes framed, just pure data. it is RS232 level, inverted TTL signal would be ok.
But at the port of the transimitter(called HOST), it is 10-bytes framed. My understanding is that introduction of the 10-bytes-frame would facilitate to decode both user bytes and the in-built telemetry bytes.
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Old Feb 25, 2010, 05:26 AM
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Quote:
Originally Posted by RobertWing View Post
The serial port of the receiver(also called REMOTE), it is "NOT" 10 bytes framed, just pure data. it is RS232 level, inverted TTL signal would be ok.
But at the port of the transimitter(called HOST), it is 10-bytes framed. My understanding is that introduction of the 10-bytes-frame would facilitate to decode both user bytes and the in-built telemetry bytes.
Thankyou Robert
So the framing is done within the return link, ok. Is there any buffering at the remote, or do we need to pause the RS232 stream every 10 bytes at the RX232 pin? And at the host end I will need some simple processing to separate out the telemetry channels and the user channel, based on the headers... is that correct?
Thank you
Phil
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Old Feb 25, 2010, 05:26 AM
Martin - AKA mr.sneezy
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Two more small observations

Three actually...

One. The TX module uses a switching regulator to drop the battery voltage from the radio (the actual RC transmitter) down to 3.3V, not an inefficient and heat producing linear regulator. Battery life of the RC TX should be very good.

Two. The TX module has a MAX232 chip buffering the serial I/O. Nice, better than raw out of the micro.

Three. The transceiver PCB is virtually identical to the one used in the Corona units (a third party module). It looks so close I'd expect I could unplug one from a Corona module and fire it up on this one. Might do that once I've run out of other uses for it in case it smokes :-P

I guess the first step is hook the TX serial output to a PC terminal app like Hyperterm and see what is really spewing out of it.

Could be a few days before I get there. (Harder since I left the documents at work)
If anyones done that could they post a screen dump ?
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Old Feb 25, 2010, 05:51 AM
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Originally Posted by PLMS View Post
...Maybe Mr Chase Wu would be kind enough to post the PDF here as attachments for us all. The more people see the info the faster we can get some hardware built.
I'll second this, eagerly awaiting to jump on it
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Old Feb 25, 2010, 05:56 PM
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Originally Posted by phil_g View Post
Thankyou Robert
So the framing is done within the return link, ok. Is there any buffering at the remote, or do we need to pause the RS232 stream every 10 bytes at the RX232 pin? And at the host end I will need some simple processing to separate out the telemetry channels and the user channel, based on the headers... is that correct?
Thank you
Phil
There should be a buffer, because the remote can not sense when to stop.
and my guess is the same as yours, based on the headers, we can separate the telemetry channels and the user channel.
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Old Feb 25, 2010, 05:58 PM
Martin - AKA mr.sneezy
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Small video

I took a quick and short video last night showing the two way system on the bench. Just an RC functional test, nothing too exciting yet, but it does show the test box I made a while ago for making module testing and range testing much easier for me.
If any of you guys can program PIC micros you can make yourself one. I can post a link to the details if anyone would like it.
Martin

FrSky Two Way 2.4Ghz system development kit first look (1 min 47 sec)
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Old Feb 25, 2010, 08:30 PM
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Martin,

Thanks for posting the video.......its a Good Idea making that Sweeping Gadgets.........one advantage of getting the High End Transmitter such as JR 10X it has a Built-in Sweeping Servo under the Servo Monitor, Futaba 9CHP has one also.........Unfortunately, the Spektrum DX7 Do not have a Sweeping servo, but has a Servo Monitor only.

I guess, We are so eager to see it you Hook it up on a PC using a simple HyperTerminal to transmit and Received......You can use Hyperterminal to Capture all Received data, then all Captured Data can easily import to EXCEL Spread Sheets in CVS format, then use EXCEL to create all kinds for Bar Graph charts

Ellion
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Old Feb 25, 2010, 08:53 PM
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[QUOTE=PLMS;14447682]If any of you guys can program PIC micros you can make yourself one. I can post a link to the details if anyone would like it.
Martin[QUOTE]

Martin, I can program PIC micros and I am interested. Thanks.
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Old Feb 25, 2010, 10:30 PM
Martin - AKA mr.sneezy
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Protocol PDF and discussion thread

Guy's,

This thread seems like it's best left as a very general FrSky discussion...
So I thought it was a good time to branch out to a new thread for pure discussion of the nuts and bolts of the telemetry protocol.

Both FrSky documents I was sent are there in PDF are there to download.
http://www.rcgroups.com/forums/showt...php?p=14449925
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Old Feb 25, 2010, 11:09 PM
Martin - AKA mr.sneezy
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[QUOTE=JMP_blackfoot;14449131][QUOTE=PLMS;14447682]If any of you guys can program PIC micros you can make yourself one. I can post a link to the details if anyone would like it.
Martin
Quote:

Martin, I can program PIC micros and I am interested. Thanks.
Follow the link to my homepage about this project.
http://flying.model.airplanes.isgrea...generator.html

If you have questions about it please PM me or post it in a new thread and send me the thread ID. I don't want to hijack this thread.
I really hope it's self explanatory and I don't get questions :-)
Martin
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Old Feb 25, 2010, 11:22 PM
Martin - AKA mr.sneezy
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Originally Posted by lazy-b View Post
one advantage of getting the High End Transmitter such as JR 10X it has a Built-in Sweeping Servo under the Servo Monitor, Futaba 9CHP has one also.........Unfortunately, the Spektrum DX7 Do not have a Sweeping servo, but has a Servo Monitor only.
I didn't know that. I use two very old but very sturdy Futaba 8U radios, and also a Hitec Flash4/5. I'd like a high end TX eventually for sure, but as I do a lot of slope soaring near the sea and they do get salty and sandy, it would not be good for it. One day...
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Old Feb 25, 2010, 11:46 PM
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Get a second T9C for $150-200 and you will not look back
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Old Feb 28, 2010, 07:48 AM
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Originally Posted by kneedrag View Post
First run we had the aerial point directly towards the rx. First 20m were jitter filled and we lost range at about 50m. That is the worst transmitter setup scenario. (for those that don't know pointing your aerial straight at a rx is not conducive to it getting signal)

.
Thats strange, I dont think any 2,4ghz receiver should get 20-50 meters range in worst scenario

I did get 400 meters with a little Corona dsss 4ch receiver poiting both TX and RX at each other and with my body in the way also..

I could not imagane getting 20-50 meters with any 2,4ghz receiver I have, even if i did remove TX antenna from module.

This was a bad result I think. Are you sure after 20 meters the servo started glitching ?
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Old Feb 28, 2010, 08:39 AM
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Wow... bad indeed... Hitec demo indoor without any antenna at all !
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Old Feb 28, 2010, 02:59 PM
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Yip it supprised me as well. However that being said as soon as the tx areial was angled no issues.

I do want to do this test again as well as with a Spektrum tx and rx.

Quote:
Originally Posted by sebbe View Post
Thats strange, I dont think any 2,4ghz receiver should get 20-50 meters range in worst scenario

I did get 400 meters with a little Corona dsss 4ch receiver poiting both TX and RX at each other and with my body in the way also..

I could not imagane getting 20-50 meters with any 2,4ghz receiver I have, even if i did remove TX antenna from module.

This was a bad result I think. Are you sure after 20 meters the servo started glitching ?
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