IBUS Protocol Decoded

[jmcordobamendez]

I have been working with the FS-IA6B Receiver of FLYSKY for a personal project. I was searching for documentation about how the IBUS protocol works and there weren't many information about it. So, i used a logic analyzer to decode the message and i'm going to share the information that i could get (maybe it is usefull for someone).

IBUS protocol is a serial protocol which uses UART/USART (115200 bps) protocol to send data segments in packages of 16 bits (little endian). The first 16 bits package is a header, the folowing ones are 16 bits packages representig the 14 channels supported by the protocol (in my case the transmitter "FS-I6" only uses 6 channels so the others channels can be ignored) and finally a 16 bits Checksum package to ensure a corret data trnasmision.

I was testing with the logic analyzer which part of the radio controller is represented by each channel getting the folloowing data:

[jmcordobamendez]

Important, the message is packaged using little endian. So the less significant bit is the first transmitted in the 16 bit package. For example, in the channel 1 what we have is the following value: CH1 = 0x05DC = 1500 (in decimal number).

[jmcordobamendez]

Here is the radio controller to check the contol parts of the table.

[hmeijdam]

Interesting... Are you developing something that the IbusBM library cannot do?