Hello All,

I am implementing a MODBUS RTU protocol on an 8-bit processor. I have my messaging constructed but looking into the protocol framing of each of the 8-bit packages.

Within the spec, I see there is a reference to the Frame length is 10-bit (even/odd parity and 1 or 2 stop bits). I am assuming that each 8-bit frame will have an additional 2 bits added?

Should the rest of the bits of the 12-bit array be set to zeros or ones?

Thanks for the clarification.

Thanks,
Ryan

 

Ryan,

It might be best to look at a simple PC program before implementing the protocol on your 8-bit processor. I have free and open source code here that should be easy to study:

http://ctrlterm.com/custom.htm

Regards,
Paul