Futaba R7008SB FASSTest S.BUS/S.BUS2 problem

[Xian06]

Hi

I have problem with Pixhawk and Futaba 14SG connection. Pixhawk dont detect S.BUS signal from R7008SB(Mode B   Port 8 /S.BUS).

I found this problems:

1,

"The Futaba R7008SB receiver has a slight modification to the S.Bus protocol compared to the other receivers.
Instead of sending all zeros as the end of frame byte, it sends a rotation of the following bytes: (12CH mode)
00000100
00010100
00100100
00110100

If we mask out the counter bits, we get an end byte of 0x04 for this particular receiver. "

This is maybe not problem because endbyte do not use.

2,

By default  Pixhawk S.BUS speed 100.000 b/s. Futaba use same speed.

Default frame:   3ms data  + 7ms space

12CH mode :    3ms data  + 3.3ms space

14CH mode:     3ms data  + 15ms space

This is maybe not problem because data same size.

Thanks

[Xian06]

First I use most compatible 12CH mode for testing.

But I do not understand why do not working in this mode.

Frame data size is same with original size  in sbus.c file,3ms.

Endbyte still not problem because dont use endbyte for detect frames.

In openpilot website has a patch that use only an endbyte fix and working.

Maybe this 3 input type in 1 pin too slow and more than 3.3ms frame space.  

Today I try to modify control.c and remove dsm and ppmsum parts.