AM32 ESC pass-through and kiss telemetry issue.

[Sibre3]

As requested by @sensei-hacker. I have copied some information from a discord forum report by @AlkaMotors
The telemetry issue only seems to be a problem for iNAV and AM32. iNAV works correctly when communicating with Blheli32 telemetry.

The following is a copy of that transcript.

We have been getting report of inav not connecting properly to the config tools for am32. It's seems when the button to read esc settings is pressed inav is outputting data before the init. This causes the esc to reset, and settings cannot be read. After resetting the fc a few times it will sometimes work properly. I hooked up a scope to see what is happening. This is without an esc attached.

This picture above shows a proper init command that is sent from inav. There are a number of zeros followed by the init command.

A large chunk of data. Then the zeroes and the init sequence. This will not work with the config tools. There is no esc attached on these shots.
Why is inav sending additional data before the init sequence ?
In the inav code the init sequence it should be sending is this -

Where is that additional data coming from before the bootinit in the bottom scope shot.
To reproduce the issue. update to inav 8.0.1 go to esc-configurator.com and press read.
It works about 1 in 10 resets of the FC.

It's causing us lots of headaches on am32. If you keep pressing connect eventually it will send a packet properly.

This extra serial data before the intended packet causes the esc to reject the command and reset of course so we have to get people to install BF update the esc then go back to inav.

The protocol is correct. The avrrootloader.c has the right buffer for bootinit and SOMETIMES is works.. Just most of the time there data sent before the bootinit. I will look into the passthrough code for INAV but i am not very familiar with it.

[sensei-hacker]

I wasn't able to reproduce the issue, but if you want to test I can give you a target that MIGHT fix it.
I can't guarantee it will fix it since I can't reproduce it in a test.

[Sibre3]

Do you mean you could not reproduce the AM32 configuration tool connection issue? Or the ESC telemetry issue?

I would have tested it. But I just drowned my only AM32 ESC and its quad in a lake. So I shall have to wait until I get some more hardware.

I also found this iNAV issue report on the matter #10764

[sensei-hacker]

The esc-configurator issue.

[Patronics]

I believe I'm encountering the same telemetry issue in inav 9.0.0, which I described in more detail in issue #10764, though I am able to access the ESC configurator fine on my end.

[AlkaMotors]

@Patronics The issue at the top of this post is very diferent. This is about the useless data being sent fro inav before the init request. This bug still exists but has nothing to do with telemetry.