New WLToys Protocol V977

Just an FYI:
I've never had a need for more than 8 pins when doing SPI for RC protocols. 8-pins willallow you to snoop both ends of an SPI bus at once if needed (though you'd miss the CE pin, which is generally not an issue).

Nothing wrong with a Salea16, but it is overkill for SPI work. On the other hand, the ability to capture very long samples (minutes worth) is really valuable, and makes the Salea design superior to a trigger/sample based system.

It is usually possible to develop the protocol from a single Tx, but it really depends on the protocol. You may end up with a protocol that only binds to exactly one model, or not have robust separation (so that two transmitters cannot be on at once). It can also be difficult to figure out what packets are constsnt, or tx specific. You may need to wire up SPI to the Rx (if possible).

Examples:
Devo: required a few transmitters due to variations between the 6/8/10 (this is the 1st one we did, so we probably could have gotten by without it if we knew more)
DSM: required multiple transmitters and multiple Rx to figure out the challenge/response
J6Pro: only needed one transmitter
Flysky: required multiple tx to determine robust txid and frequency hopping
Hubsan: only needed one tx. A 2nd was used for confirmation though
Frsky1/2: Only needed one tx (though it isn't actually done yet)
Skyartec: Only needed one Tx