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Frsky compatibility
- PhracturedBlue
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20 Feb 2014 02:09 #20623
by PhracturedBlue
Replied by PhracturedBlue on topic Frsky compatibility
Correct. My code works fine with a non-PA CC2500. It does not work with any of the PA/LNA modules I have though. It mystifies me, since I'd expect the frequency of each to be identical.
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- midelic
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20 Feb 2014 02:27 - 20 Feb 2014 02:30 #20625
by midelic
Replied by midelic on topic Frsky compatibility
I'm thinking.I have an idea not sure is good .It maybe that the pa/lna on cc2500 shift on the output,.. the original frequency set on the cc2500 registers.
You now that "Kreature" guy has uploaded on rcgroups forum one frequecy scanner code for cc2500.
Im thinking to use this scanner(or other scanner) and check the frequencies from pa/lna cc2500 chip.In base of that play with the cc2500 frequency register to match the required output.
This an idea maybe working maybe not(we know already with the bare chip is working) ..I want to try.
You now that "Kreature" guy has uploaded on rcgroups forum one frequecy scanner code for cc2500.
Im thinking to use this scanner(or other scanner) and check the frequencies from pa/lna cc2500 chip.In base of that play with the cc2500 frequency register to match the required output.
This an idea maybe working maybe not(we know already with the bare chip is working) ..I want to try.
Last edit: 20 Feb 2014 02:30 by midelic.
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- PhracturedBlue
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20 Feb 2014 02:39 #20626
by PhracturedBlue
Replied by PhracturedBlue on topic Frsky compatibility
I have an SDR that I used to snoop the signal. I can see that the frequency is different when using the PA, it is also wider (uses more bandwidth). I could not find any settings that would move the frequency enough to get it to align with the non-PA version though. It really was driving me crazy. It's been a year since I worked on it though.
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- midelic
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20 Feb 2014 02:45 - 20 Feb 2014 02:49 #20627
by midelic
Replied by midelic on topic Frsky compatibility
For the moment I don't have one pa version...to test.
I'll buy one and test myself.Hope it will not take one year.
I don't know if you play with but I think the key is modifying FREQ1,FREQ0,FREQ2 registers.
I'll buy one and test myself.Hope it will not take one year.
I don't know if you play with but I think the key is modifying FREQ1,FREQ0,FREQ2 registers.
Last edit: 20 Feb 2014 02:49 by midelic.
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- blackmoon
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20 Feb 2014 06:47 - 20 Feb 2014 06:51 #20637
by blackmoon
Replied by blackmoon on topic Frsky compatibility
Like blossoms, hopes live and die...
Answer from the eBay vendor :
Anyway, as the non-PA modules work, I can still use the skyartec module to bind to the cheap micro receiver VD5M. That's enough for me and indoor planes.
Answer from the eBay vendor :
hi,the stock item is V8FR-II HV now.
Anyway, as the non-PA modules work, I can still use the skyartec module to bind to the cheap micro receiver VD5M. That's enough for me and indoor planes.
Last edit: 20 Feb 2014 06:51 by blackmoon.
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- PhracturedBlue
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20 Feb 2014 09:28 #20642
by PhracturedBlue
Replied by PhracturedBlue on topic Frsky compatibility
The skyartec module doesn't work (it has a PA). I don't remember which one I have, but anything with an on-board antenna like the:
www.ebay.com/itm/1-8-3-6V-CC2500-IC-Wire...&hash=item41698f4a84
Should work.
www.ebay.com/itm/1-8-3-6V-CC2500-IC-Wire...&hash=item41698f4a84
Should work.
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- blackmoon
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20 Feb 2014 11:19 #20646
by blackmoon
Replied by blackmoon on topic Frsky compatibility
Thx for the reminder, you saved me some headaches. I'll forget Frsky, until and if, it's solved.
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- IMback!
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20 Feb 2014 17:09 - 20 Feb 2014 17:11 #20652
by IMback!
Replied by IMback! on topic Frsky compatibility
I assume SKYARTEC works with non pa modules? If The pa shifts the freq why isnt SKYARTEC affected? whats diffrent? Just wondering.
Last edit: 20 Feb 2014 17:11 by IMback!.
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- PhracturedBlue
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20 Feb 2014 18:43 #20655
by PhracturedBlue
Replied by PhracturedBlue on topic Frsky compatibility
If I understood what was wrong, I could probably fix it. It don't and it makes no sense to me.
My non-PA modules work fine with Skyartec and Frsky.
MyPA modules work only with Skyartec.
I have no idea what the difference is. the PA should not cause any frequency shift.
My non-PA modules work fine with Skyartec and Frsky.
MyPA modules work only with Skyartec.
I have no idea what the difference is. the PA should not cause any frequency shift.
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20 Feb 2014 19:29 - 20 Feb 2014 19:32 #20660
by IMback!
Replied by IMback! on topic Frsky compatibility
Ok that sucks. Using trail and error with diffrent cc2500 modes (maybe implenting a custom protocoll) might give us somthing to go on but its alot of work and a sprectum analyzer would be a must. Btw is there a reason skyartec is the only protocoll that dosent implent changing the power output or was it just low priority.
Last edit: 20 Feb 2014 19:32 by IMback!.
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- midelic
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20 Feb 2014 20:23 - 20 Feb 2014 20:30 #20662
by midelic
Replied by midelic on topic Frsky compatibility
My non pa module is not working with your frequencies....
CC2500_WriteReg(CC2500_0E_FREQ1, 0x76);
CC2500_WriteReg(CC2500_0F_FREQ0, 0x27);
I cannot bind.
but it works with,
cc2500_writeReg(CC2500_0E_FREQ1, 0x75);values
cc2500_writeReg(CC2500_0F_FREQ0, 0x6A);//
So i wonder if non pa modules have different frequencies.
I test also with:
cc2500_writeReg(CC2500_0E_FREQ1, 0x75);values
cc2500_writeReg(CC2500_0F_FREQ0, 0x27);
an working..so the difference
cc2500_writeReg(CC2500_0E_FREQ1, 0x75);//working
versus
cc2500_writeReg(CC2500_0E_FREQ1, 0x76);//not working
CC2500_WriteReg(CC2500_0E_FREQ1, 0x76);
CC2500_WriteReg(CC2500_0F_FREQ0, 0x27);
I cannot bind.
but it works with,
cc2500_writeReg(CC2500_0E_FREQ1, 0x75);values
cc2500_writeReg(CC2500_0F_FREQ0, 0x6A);//
So i wonder if non pa modules have different frequencies.
I test also with:
cc2500_writeReg(CC2500_0E_FREQ1, 0x75);values
cc2500_writeReg(CC2500_0F_FREQ0, 0x27);
an working..so the difference
cc2500_writeReg(CC2500_0E_FREQ1, 0x75);//working
versus
cc2500_writeReg(CC2500_0E_FREQ1, 0x76);//not working
Last edit: 20 Feb 2014 20:30 by midelic.
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- sbstnp
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20 Feb 2014 20:58 - 20 Feb 2014 20:58 #20664
by sbstnp
Devo 10 + 4in1
Spektrum Dx9
FrSky Taranis + TBS Crossfire
Replied by sbstnp on topic Frsky compatibility
Could these differences be due to crystals or caps?
Devo 10 + 4in1
FrSky Taranis + TBS Crossfire
Last edit: 20 Feb 2014 20:58 by sbstnp.
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- PhracturedBlue
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21 Feb 2014 04:10 - 21 Feb 2014 04:11 #20678
by PhracturedBlue
Replied by PhracturedBlue on topic Frsky compatibility
Well...This is just weird.
I took the code exactly as is (using FREQ1=0x76), and I was able to bind and control the 2-way protocol using my skyartec cc2500 (w/PA but I do not currently have an antenna attached). I was using my RPi and the signal wasn't stable (kept losing lock). i need to hookup SPI and see if it is RPi related or some tuning.
This is a different module than I had previously used. So it is possible that some amount of tuning is needed for each module to get it to work.
As a side note, last time I worked on this, I swept the 'FREQ1' value through the entire range and was unable to bind with my other CC2500 module.
So now I need to go through each of my CC2500 modules and see if I can reproduce the current behavior.
I took the code exactly as is (using FREQ1=0x76), and I was able to bind and control the 2-way protocol using my skyartec cc2500 (w/PA but I do not currently have an antenna attached). I was using my RPi and the signal wasn't stable (kept losing lock). i need to hookup SPI and see if it is RPi related or some tuning.
This is a different module than I had previously used. So it is possible that some amount of tuning is needed for each module to get it to work.
As a side note, last time I worked on this, I swept the 'FREQ1' value through the entire range and was unable to bind with my other CC2500 module.
So now I need to go through each of my CC2500 modules and see if I can reproduce the current behavior.
Last edit: 21 Feb 2014 04:11 by PhracturedBlue.
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- blackmoon
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21 Feb 2014 08:39 #20691
by blackmoon
Replied by blackmoon on topic Frsky compatibility
A friend gave me a V8FR so I could test if the module works with deviation and later install it on his devo.
But before destroying a perfectly working receiver, I'll wait for the dust to settle on this, because I have two skyartec modules and if it would work with them, it would be preferable.
But before destroying a perfectly working receiver, I'll wait for the dust to settle on this, because I have two skyartec modules and if it would work with them, it would be preferable.
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- midelic
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21 Feb 2014 14:13 - 21 Feb 2014 14:29 #20696
by midelic
Replied by midelic on topic Frsky compatibility
My non pa module is different ,I took it from aliexpress ..it has cylindrical x-tal.
Normally should bind on 2404 base freq .....but bind lower with min 15 khz(76/00)...and It dropped also a lot of frames...I can control a servo but delayed.
These are bad news ..i don't think it can be standardized for all modules.Maybe similar module may behave differently.
I think frsky tune hardware(component selection) both tx and rx modules on the same freq....
The freq values to be change are FREQ1 and FREQ0...try sweeping both registers.
FREQ 2/1/0 make 24 bits word...normally on frsky 0x5c7627 equal 2404GHZ.
Fcarrier=Fosc*FREQ[23:0]/65536
Normally should bind on 2404 base freq .....but bind lower with min 15 khz(76/00)...and It dropped also a lot of frames...I can control a servo but delayed.
These are bad news ..i don't think it can be standardized for all modules.Maybe similar module may behave differently.
I think frsky tune hardware(component selection) both tx and rx modules on the same freq....
The freq values to be change are FREQ1 and FREQ0...try sweeping both registers.
FREQ 2/1/0 make 24 bits word...normally on frsky 0x5c7627 equal 2404GHZ.
Fcarrier=Fosc*FREQ[23:0]/65536
Last edit: 21 Feb 2014 14:29 by midelic.
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- PhracturedBlue
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22 Feb 2014 05:29 #20729
by PhracturedBlue
Replied by PhracturedBlue on topic Frsky compatibility
I guess you have this one:
www.aliexpress.com/item/10pcs-Lot-CC2500...pping/587066731.html
That is the non-PA module I have (actually I have 3 of them, but I've only wired one). I just verified, and the one I have wired works just like my Skyartec module I tested yesterday (base frequency=0x5c7627) So if that doesn't work for you using the same module, it implies that we need to find some way to calibrate these modules. I'm not sure if the hardware I have available has enough impedance to measure the oscillator frequency to compare to the frsky module
www.aliexpress.com/item/10pcs-Lot-CC2500...pping/587066731.html
That is the non-PA module I have (actually I have 3 of them, but I've only wired one). I just verified, and the one I have wired works just like my Skyartec module I tested yesterday (base frequency=0x5c7627) So if that doesn't work for you using the same module, it implies that we need to find some way to calibrate these modules. I'm not sure if the hardware I have available has enough impedance to measure the oscillator frequency to compare to the frsky module
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- midelic
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22 Feb 2014 14:21 - 22 Feb 2014 15:26 #20738
by midelic
Replied by midelic on topic Frsky compatibility
Yes that's the one I have.It is not working on base frequency.I left the FREQ registers on original settings 0x5c7627...and i modified the FREQOFF freq offest , FSCTRL0 register(0XD7 working ,instead of 0x00).However ,I have dropped frames..From time to time the RED led is on.Did you test your code with VD5M rx on 2 way mode?
I think the frequency is shifting in time...with this one.I ordered new one from ebay I'm curious to see if working the same.
I think the frequency is shifting in time...with this one.I ordered new one from ebay I'm curious to see if working the same.
Last edit: 22 Feb 2014 15:26 by midelic.
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- midelic
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22 Feb 2014 22:07 #20760
by midelic
Replied by midelic on topic Frsky compatibility
I fixed the problem with dropped frames ,made some code mistakes..now no more dropped frames.working ok.
But the main problem remains,,I made it work with this module...when I shift the base frequecy....hacking FSCTRL0 register....
I believe with the pa module some aproach must be done change values of FREQOFF[7:0]..in FSCTRL0 ....
But the main problem remains,,I made it work with this module...when I shift the base frequecy....hacking FSCTRL0 register....
I believe with the pa module some aproach must be done change values of FREQOFF[7:0]..in FSCTRL0 ....
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- PhracturedBlue
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22 Feb 2014 22:37 - 22 Feb 2014 22:39 #20761
by PhracturedBlue
Replied by PhracturedBlue on topic Frsky compatibility
I checked the oscillators on my non-PA module against the Frsky module. I can't measure the difference in my oscillosope, so whatever the differences, it is beyond my ability to detect.
We'll likely need to find a way to tune the module. I'm not sure how. Maybe add a special mode to sweep the freq-adjustment until locking and then save the value.
Did you find code mistakes in my code? I'm not sure what the best way to try to find the proper frequency adjustment.
We'll likely need to find a way to tune the module. I'm not sure how. Maybe add a special mode to sweep the freq-adjustment until locking and then save the value.
Did you find code mistakes in my code? I'm not sure what the best way to try to find the proper frequency adjustment.
Last edit: 22 Feb 2014 22:39 by PhracturedBlue.
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- midelic
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22 Feb 2014 23:05 - 22 Feb 2014 23:15 #20767
by midelic
Replied by midelic on topic Frsky compatibility
No, your code is good as it is .....I tried to write my own(I'm using BB instead of HW spi to free some pins) in arduino,,..tried to avoid copy your interrupt timer routine(not happy to put 2 interrupts routines on same timer...)...and in the process I made some mistakes.Anyway the frequency shift is there..and is very small around 15Khz...
I'm using...
cc2500_writeReg(CC2500_0C_FSCTRL0, 0xd7); otherwise not working.
About the offset...trial and error....not sure but I think over 128 decrease the base freq and till 128 increase the freq...just guessing based on my experience....according with data sheet is ±202 kHz to ±210 kHz,
I think the base freq must be exactly in tune with rx base freq otherwise not binding...I'll do some more tests.
I'm using...
cc2500_writeReg(CC2500_0C_FSCTRL0, 0xd7); otherwise not working.
About the offset...trial and error....not sure but I think over 128 decrease the base freq and till 128 increase the freq...just guessing based on my experience....according with data sheet is ±202 kHz to ±210 kHz,
I think the base freq must be exactly in tune with rx base freq otherwise not binding...I'll do some more tests.
Last edit: 22 Feb 2014 23:15 by midelic.
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