How do I factory default a module should for example an incorrect baud rate be selected?

Answer

You can factory default a module using Ezurio Terminal by right clicking on the main window and selecting Factory Default/ via BREAK/COMMAND @ 9600. However should you not have access to Ezurio Terminal the procedure is as follows:

Open PC’s comport with “9600,N,8,1”

Assert PC’s RTS which is connected to module’s UART_CTS input

Deassert PC’s DTR which is connected to module’s UART_DSR input

Start a 1000msec timer (not essential, but I do it anyway)

On timer expire

Send a Break (OR switch off power to module)

Start a 1000 msec timer

On timer expire

Release Break (OR switch on power to module)

Flush receive buffer

Start 600 msec timer

On timer expire

Send(“!!\r”)

Start 300 msec timer

On timer expire

Send(“!!\r”)

Start 300 msec timer

On timer expire

Send(“!!\r”)

Start 300 msec timer

On timer expire

Check receive buffer to see if at least one “OK” was received

If OK received then module is in factory default mode

If OK NOT received then please try again

What if DSR and CTS were not used, would this still be useable?

You might get away with not having CTS, but DSR is definitely required. DSR has to be deasserted when the module is powering on to go into checking for that mode.