f5soh

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    • LibrePilot
Re: Sbus inverter option
« Reply #15 on: May 09, 2017, 08:53:22 am »
Quote
RSSI is output on channel 9, and that was confusing the wizard
You just need to declare manually the channel 9 under the Rssi line, save and Rssi is ignored for normal wizard usage.

Schugy

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Re: Sbus inverter option
« Reply #16 on: November 03, 2017, 09:40:42 pm »
My Walkera RX-SBUS also uses inverted SBUS signal. It supports PPM too but I'd like to use SBUS with my CC3D. Only got some flicker (Channel 18, 1, 2, 3 ...).

SBUS inversion seems to be pretty common.

mr_w

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    • LibrePilot
Re: Sbus inverter option
« Reply #17 on: November 04, 2017, 10:12:48 am »
SBUS is by default "inverted", which means opposite (inverted) of what common UART uses. SBUS inactive line is logic low level, and active bits are represented as logic 1 (high level). UART uses the opposite way, but as it is more common it is considered as "normal", and SBUS as inverted.

On the other hand, cheaper receivers use cheaper hardware that doesn't have the capability of "inverting" the serial signal to fully comply with SBUS standard, and of course omitting external inverter (on rx side) makes thing even cheaper. Therefore, some RXes do indeed have somewhat non-standard SBUS that uses "non-inverted" UART type protocol.

Anyways, back to LibrePilot, current next does support turning off the inverter. The option to do so is accessible in HwSettings object through System tab.

Schugy

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Re: Sbus inverter option
« Reply #18 on: March 17, 2018, 09:58:58 am »
Now I'm clueless. I've installed the latest next release and activated the non_inverted SBUS option. Non-inverted there is no activity to be seen. With standard SBUS I have this "Channel 18+ used Channel" flicker.
I wonder what strange kind of SBUS the Walkera RX-SBUS uses. Maybe it's a sync problem. I have 3 receivers and they all work the same way. And they work flawlessly with my RC-Ware RX2SIM USB dongle in SBUS mode. But this has nothing to do with the topic (SBUS inverter option) anymore and I'll start a thread for it.

Re: Sbus inverter option
« Reply #19 on: March 17, 2018, 04:32:21 pm »
Generally speaking you do NOT want "non-inverted" option.  It is non-standard.  :)

If the normal channels work at all, then you have it set correctly.

The 18+ may be from some extra (non-control) receiver signal like RSSI where the RC receiver is trying to tell the FC how strong the RC signal is, so the FC can do RTB/RTL/RTH when it is out of range, or the FC/OSD can issue warnings if it is almost out of range.  These extra signals can sometimes get in the way of running the transmitter wizard when it asks you to wiggle the roll stick and it sees the extra signals before you wiggle the roll stick.