Allowed error in baud rate between pic and Bluetooth module
As a general rule of thumb, the total error between a transmitter and a receiver cannot exceed &plusmn;5% &mdash; half a bit time either way after a total of 10 bit times. Splitting this evenly between the two, and making allowances for crystal errors, synchronizer delays, etc., we usually say that each device needs to be within &plusmn;2% of the nominal frequency.