V202 protocol

This is pretty slick. So the BK2421 can communicate with the nfr24l01? That is really good news. It is the 1st chip I've seen that can do so. I've looked at your code.
Your begin statement can be translated to an init() function
command() becomes a build_data_packet() (and the tx part goes into the _cb() function. The nrf stuff goes into target/devo_common/protocol/nrf24l01.c
It looks like an easy project to convert it to a deviation module.

As you mentioned, we'd need to figure out the frequency hopping table to do this right. In the past what i did was to hook up my Salaea to the Rx, then use my test-setup (and rpi) to transmit a txid, wait an amount of time, toggle a gpio to reset the rx, and do the next one. Then I'd just run it for hours with the Salaea capturing its longest run (~ 20 minutes). This allows me to watch the Rx scan the channels for a given txid. and to push a huge number of ids through. the same thing would work just as well (probably better) with your arduino setup.

If you are setup to collect the data, that'd be great. Otherwise, once this is working in Deviation I can run the above scripts.

Also, let me know if you want to tackle the Deviation port, or if you'd like me to. With the work you've done, porting it to Deviation is probably only an hour or 2 of my time.

Oops. I remember the problem I had. You can't switch the nrf24L01 from Rx to Tx (or vice-versa) without asserting the CE pin (well, you can but requires going through 'Power Down' which is very slow. Deviation is designed to only use 1 pin (CSn) to control each module. Using a 2nd is possible, but requires some harder soldering or negates the use of 2 external modules in the same radio.

If the protocol requires Tx only, you can just tie CE high and then toggle between 'Standby-II' and 'TX Mode'. If you need Rx, you need to pass through 'Power Down' which incurs a 1.5msec cost.

I haven't looked at the BK2421 but if we could use it to talk to the full range of nrf24l01 protocols instead, and it uses a proper 4-pin protocol it may be interesting to put the BK241 module in the tx instead.

Alternatively, we could wire the 4-pin SPI ito 3-pin using a resitsor between the 2 pins and then operate it like an A7105. That would let you use the miso pin as a CE pin though I dunno what happens if you toggle CE a lot when the module is not in use.

One more option is to share the reset pin used by the cyrf6936 module. I'm notsure how the cyrf module takes to being held in reset, but if it doesn't affect power, that mightbe another option.

Edit: I just looked at the BK2423 data sheet. It's state machine looks awfully similar to the nrf24l01, and it also seems to require CE. I can't tell whether you can bypass this requirement as in the nrf chip without spending more time looking at it though.

you can see this thread:
www.deviationtx.com/forum/7-development/...module?start=20#8384

I actually use an 8-way multiplexor for CSn on my RPI test setup, and it works well. asking someone to breadboard one of these is quickly getting past most people's capabilities though, so to me it looks like something that needs to be pre-made. If we're going that way, might as well go whole-hog and actually put all the chips on one board along with an STM32 processor and then make a module that can plug into any transmitter. On a Devo you'd only use the STM32 as a mux, but they're cheap and you could then have one board design that meets the entire set of needs.

My big problem is that (a) I have very little experience mounting QFN parts, (b) I have no experience at all with designing RF circuitry (c) even if I designed the whole thing and got it working, I'm not sure about the liability of actually selling it.

For the moment I'm more likely to try one of the other solutions I proposed to get around the issue for the time being.

We could bring this to the other thread. To design a siwtch board, I'd love to basically add headers for all the common modules on a dual-sided board so you can use any of the available nrf, a7105, or cc2500 modules (as well as the old wk and new devo cyrf modules) and have the board plug into the devo socket. It would likely be possible to overlap the connectors to save space (all the a7105 connectors could overlap, etc). I'd also leave open headers that could be used for future modules as needed.

I think I'd like to use a uC instead of a switch. You could talk to it via SPI and need only 2 io:
take the cyrf reset pin as the CS for the uC, and then pass the 2nd pin as a CS to whichever module is specified. This also lets you support 5-pin modules by sending specific commands to the uC to turn on/off the relevant pins.
You could probably get by with a PIC or AVR without issue (though again, using an STM32 allows using the Deviation protocol code to build a PPM universal module (with a bunch of antennas)

The goal here would be to build something that could be easily assembled by someone without much experience. You could do that with all through-hole components I suppose (I'm not knowledgeable on AVR, but PIC has several parts with high-speed on-board resonators if accuracy isn't important..I really liked the 18f14k50 as a low-pin count USB-capable chip). In that case we'd just be building a Devo-only module. If we could actually manufacture and assemble the boards, using smaller SMT chips could make the board more capable as described above.

We can take this discussion over to the Universal Module thread. I'm certainly open to suggestions on how to proceed.

As I can see WLToys V212 use BK2423 chip.

www.rcgroups.com/forums/showthread.php?t=1873198

great to hear