How To Exit an XB8 Asynch SM4 Mode


Ho to get an XB8 radio(XB8-DMUSB002) out of Asynch Sleep Mode 4 and change to Sleep mode 0.


John, I was talking with my engineer and he was wondering if you had access to the UART to write new commands?



Hi Robert,

The answer is yes, but the module does not stay awake long enough to send commands to it.

Maybe he has some trick way of doing this.

Here is an explanation of my set up and problem.

I have connected power i.e. 3.3V to the module.

I have a LED connected on pin 26 and gnd to indicate when the radio is active.

I have the RS232 (pins 3 and 4 and Gnd) connected via a level shifter connected directly to my laptop.

I am running your software “XCTU”.

This set up serves me well to set up various parameters on the radio modules.

However while experimenting with the various sleep modes available in the module as per the “SM” command, I accidently switched the mode on a few radios to “SM4”, described as the Asynch Cycle Sleep Mode.

As you are aware this mode makes the radio sleep for the duration of the sleep time dictated by the SP setting, then it wakes for an instant (indicated by a flash on the LED). Then it goes back to sleep and repeats ths sequence over and over. This very brief wake time is not sufficient to allow one to change the sleep mode to “0” and wake up the module permanently. So these modules are now useless unless they can be taken out of the SM4 sleep mode by some method.

Thanking you in advance,



Use the following steps to recover the device to UART operation:

  1. Hold the DIN/CONFIG low at reset time.
  2. DIN/CONFIG forces a default configuration on the UART at 9600 baud and brings up the device
    in Command Mode on the UART port.
    You should be able to use XCTU to change the settings.

This is also described on page 78 of User Guide at link


Hi Robert,

I tried the solution you sent me but it did not work.

However I found on page 50 (see attached), of the manual link you sent me, how to mimic the commissioning button.

This worked a treat.

Thanks for you help on the mattter