User guide

8. Factory Default Mode
EZURiO devices are capable of operating at a very wide range of baud rates. S Registers 520 and
521 allow the baud rate to be set very easily. The baud rate clock generator in the EZURiO device
is more versatile that that available in a standard 16550 UART commonly available in PCs.
In fact, as long as the equation BAUDRATE * 0.004096 produces an integer value, there will be
0% error in clocking for that baud rate.
So it is possible to set a baud rate that a PC cannot cope with, and in that circumstance it is
virtually impossible to communicate with it.
To cater for this circumstance, the EZURiO device will come out of reset using 9600,N,8,1 comms
settings for exactly 750 milliseconds and then revert to the comms parameters as per the S
Registers.
If the host sends the string !<BISM>!<cr> where <cr> is the carriage return character within
that 750ms period, then the module will remain at 9600,N,8,1 and will also configure itself using
factory default S Register values.
DSH_50003_v1v3 AT Command Reference 31 of 33