LemonDSMP: No telemetry, and CH8 not working

[pfeerick]

Is there an existing issue for this problem?

• I have searched the existing issues

What part of EdgeTX is the focus of this bug?

Transmitter firmware

Current Behavior

When using the LemonDSMP Module, there is no telemetry from the LM0086 7CH receiver, and it appears that CH8 (and maybe also CH7 as stabilsation should still do something with minimum gain) is not working / locked to -150. I've encountered this myself, and it has been reported by another on RCG

• https://www.rcgroups.com/forums/showpost.php?p=53053491&postcount=8386
• https://www.rcgroups.com/forums/showpost.php?p=53053971&postcount=8390

MikeB has given an outline of how erskyTx does bind response, which may be useful in comparing how we handle it
https://www.rcgroups.com/forums/showpost.php?p=53056517&postcount=8405

Expected Behavior

For Telemetry to work, and for all available channels to work correctly.

Steps To Reproduce

1. Bind LM0086 RX to LemonRX DSMP module with LemonRX DSMP set as the module protocol
2. Attempt telemetry scan - nothing will be found
3. Try to use CH7/8 for stabilisation control/gain - nothing will happen
4. Configure module to be in PPM mode - i.e. set external module to PPM, power cycle module so that it syncs, CH7/CH8 should now work

Version

2.10.4

Transmitter

RadioMaster TX16S / TX16SMK2

Operating System (OS)

No response

OS Version

No response

Anything else?

I encountered this when originally testing 2.10 prior to the first RC, and was able to repo it also in 2.7.1, which is strange, as this is when it was first implemented via #1715, and was working for @raphaelcoeffic at the time. However, at the same time, I have working telemetry with the LemonRX DSMP module if using a Spektrum AR637T receiver, and if I use the MPM I got telemetry from the LM0086 receiver.

Note: this is the first gen LM0086, not the second generation LM0086X if that has any bearing on this. Unfortunately, the other only LemonRX RX I have is the LM0081, which is a no-telemetry RX. However, all channels appear to be acting weirdly - only half channel working, when in LemonRX DSMP mode, but are fine in PPM mode.

[raphaelcoeffic]

According to Mike's code on RCG, we were indeed not using the right bit mask (0x3F vs 0x47), which may or may not fix the issue. I don't have anything to test this, so I don't know whether or not this fixes anything.