XK Protocol Question

Hi victzh,

Here comes SF700S top & bottom picture,hope it could help.

Thanks, it helps! It is very accessible design, lots of room to solder.

Check out Builds sub-forum, I put versions for Devo 7E and Devo 10 there.

Thousand thanks, I hope I manage to test it the next weeks. Has anybody tested this and can give feedback?

I tested XK K110 and XK K120 - a great result, everything is working!

victzh wrote: Check out Builds sub-forum, I put versions for Devo 7E and Devo 10 there.

Many, many thanks to you, and all others contributed to the project!!!!.

May be I missed, I am not able to find source of the CC2500 module used in TX, can you please post again?

I have a BNF K110, waiting for a working radio.

eBay, Banggood, whatever is better for you. E.g. www.ebay.com/itm/CC2500-PCBA-2-4GHz-Wire...c:g:mt8AAOSwFNZWzB5M or www.ebay.com/itm/New-CC2500-PA-LNA-Romot...6:g:g8gAAOSwHPlWcXME . They both need an antenna, the second one has U.FL on it, the first one requires soldering.

Babay wrote: Today I received CC2500 module, and will install it into Devo transmitter. It is unfortunate that Futaba S-FHSS protocol has not yet been implemented. Dear developers, please help to implement the protocol. This would allow to use of high-quality receivers through S.BUS. And many people will be able to tell: Thank you very much!

Can you please share the source and the picture in your TX?

Thank you!!!

victzh wrote: eBay, Banggood, whatever is better for you. E.g. www.ebay.com/itm/CC2500-PCBA-2-4GHz-Wire...c:g:mt8AAOSwFNZWzB5M or www.ebay.com/itm/New-CC2500-PA-LNA-Romot...6:g:g8gAAOSwHPlWcXME . They both need an antenna, the second one has U.FL on it, the first one requires soldering.

Thank you victzh! The second one looks better, it has a shield. The first one has more Max TX power (22 vs. 17 dbm).

jimqjp wrote: Can you please share the source and the picture in your TX?

Pictures, diagram and link for source present in my blog . Sorry, the text in Russian. But now, this module is not available.

Man, but what you write in your blog is not totally the truth. You write: "It appears the developers were not aware about cheaper Futaba alternatives. Only recently thanks to coordinated efforts we pointed developers to cheaper XK Innovations models".

It's just not true. I started hunting XK Alien X250 as soon as it was announced that it would be Futaba S-FHSS compatible, which later appeared not to be true. Only recently actual S-FHSS models with transmitter were available. When I learned of it, not from you, by the way, I immediately bought it with my own money, and also bought Orange S-FHSS receiver and started reversing it. So, I don't like this condescending tone.

Babay, thank you, the blog is very helpful.

Finally, I received a blue CC2500 module from BG

www.banggood.com/CC2500-PA-LNA-Romote-Wi...F24L01-p-922595.html

BG does not carry another kind, which has a few dbm more power, anymore.

This is a connection picture works for my 7E (step 1).
static.rcgroups.net/forums/attachments/5...7E-CC2500-Mod_01.jpg

There are more info here for the installation.
www.rcgroups.com/forums/showthread.php?t=2462580

Replaced a a7105 module in my 7E with this one, I have not played V911 for a long time anyway. Really wish I could have another spare pin for this one.

Thanks again for great contribution of Victzh and others, the protocol works smoothly.

Here are the channel info may help:

ch1 - AIL
ch2 - ELE
ch3 - THR
ch4 - RUD
chr5 - 6axel / 3D
ch6 - pitch

The power setting for CC2500 seems not correct.

I found that my 7E uses 180mA for all CC2500 settings but the very first one (0.3mW). Then I checked the code.

The power is set in this function:

void CC2500_SetPower(int power)
{
const unsigned char patable[8]=
{
0xC5, // -12dbm
0x97, // -10dbm
0x6E, // -8dbm
0x7F, // -6dbm
0xA9, // -4dbm
0xBB, // -2dbm
0xFE, // 0dbm
0xFF // 1.5dbm
};
if (power > 7)
power = 7;
CC2500_WriteReg(CC2500_3E_PATABLE, patable[power]);
}

The power level we need should be
TXPOWER_100uW, -10 dbm
TXPOWER_300uW, -5.22 dbm
TXPOWER_1mW, 0 dbm
TXPOWER_3mW, 4.7 dbm
TXPOWER_10mW, 10 dbm
TXPOWER_30mW, 14.77 dbm
TXPOWER_100mW, 20 dbm
TXPOWER_150mW, 21.76 dbm

The amplifier of the module adds about 20dbm power. So the CC2500 setting should be about -30 dbm to 0dbm.

Based on the datasheet, the power table in this function should be like this:

const unsigned char patable[8]=
{
0x50, // -30dbm TXPOWER_100uW, -10 dbm
0xC0, // -26dbm TXPOWER_300uW, -5.22 dbm
0x46, // -20dbm TXPOWER_1mW, 0 dbm
0x55, // -16dbm TXPOWER_3mW, 4.7 dbm
0x97, // -10dbm TXPOWER_10mW, 10 dbm
0x7F, // -6dbm TXPOWER_30mW, 14.77 dbm
0xFE, // 0dbm TXPOWER_100mW, 20 dbm
0xFF // 1dbm TXPOWER_150mW, 21.76 dbm
};

Now my radio current changes from 120mA to 180mA with the power level settings.

Can not believe rx sf700s is very simple and component cheap

Can you try to read hex file from stm8 with a Stlink , dc59 ? Good luck

john wrote: Can not believe rx sf700s is very simple and component cheap

Can you try to read hex file from stm8 with a Stlink , dc59 ? Good luck

How to wire my ST-Link to SF700S to read HEX file?

dc59 wrote: Hi victzh,

Have 4 pad soder at bottom pcb , that is Reset , vcc (3v3) gnd , swim . Connect them to Stlink usb and use Stlink unity same Goesbish did

Woa woa ... I had successful ,I borrowed rx my friend, I read firmware ok from stm8 , maybe lucky because it not protected .
Load firmware again , it work normal

I can't connect my SF700S to ST-Link and now I got problem, my SF700S can't work!

Dose pin order from left to right at bottom side Reset , vcc (3v3), gnd , swim correctly?

dc59 wrote: I can't connect my SF700S to ST-Link and now I got problem, my SF700S can't work!

Dose pin order from left to right at bottom side Reset , vcc (3v3), gnd , swim correctly?

Omg , I'm sorry for this
Reset , gnd , vcc, Swim . Hope stm8 not burn .
If it bad , I will send you file bin to load firmware . But you have to replace new chip st8