Is there any way that help me convert s-bus signal in to RS 2 3 2 signal? Do I need any special device to do that?

Thank you.

I'm not familiar with S-Bus but having a quick look I don't think there is a simple solution, you need the right parts.

Do you really need to convert it to RS232 or do you mean to logic level signals that you can feed into the uart on an mbed? These aren't the same thing, if you connected RS232 directly to an mbed CPU you could blow it up.

S-bus looks to be a protocol running on top of an RS485 link. So something like this part: https://www.sparkfun.com/products/10124 would let you connect the S-Bus in to the mbed UART, the rest would then be software to handle the S-Bus protocol side of things. (9600 baud and a fixed packet structure)

If the plan is to take power from the S-Bus connection to power the mbed then you'd also need a voltage regulator of some sort to bring the voltage down to something the mBed can cope with, s-bus is up to 32V. Something like this https://www.sparkfun.com/products/107 would probably work fine as long as you have at least 8V on the bus (which is the minimum that s-bus should supply.)

If you need to connect it to RS232 then you will also need an RS232 line driver to convert from the logic level signals to the +/-15V that RS232 uses.

S-bus is a 100.000 baud inverted protocol. There is an Arduino library that handles this,I use it with my FrSky rc receivers. Maybe you can port it to mbed:

http://forum.arduino.cc/index.php/topic,99708.0.html

Edit: Oops I see now that it was originally ported fromm mbed to Arduino

S-bus is a 100.000 baud inverted protocol. There is an Arduino library that handles this,I use it with my FrSky rc receivers. Maybe you can port it to mbed:

http://forum.arduino.cc/index.php/topic,99708.0.html