I have configured modbus rtu slave with no parity and 1 stop bit. It is responding to both 1 stop bit and 2 stop bit request. If I configured slave with 2 stop bit it responds only to 2 stop bit request, so there is no issue with 2 stop bit configuration.
Please let me know any solution it. Thank you
I am sending packets to my device over serial connector through modbus doctor tool which acts as master.
A byte with two stop bits is a fully valid byte with one stop bit followed by one more high bit.
Since the idle state of the line is high, then this is completely indistinguishable from a byte with one stop bit followed by a small idle gap between bytes.
This means the behaviour you have observed is correct and expected. If you want to use only two stop bits then configure this at the transmitter.