Enable the on-chip brown out detect function.
Some PICAXE chips have a programmable internal brown out detect function, to automatically cleanly reset the chip on a power brown out (temporary voltage drop below the minimum operating voltage). The brown out detect is always enabled by default when a program runs.
However it is sometimes beneficial to disable this function to reduce current drain in battery powered applications whilst the chip is 'sleeping'. However you must still ensure that the operating voltage does not drop below the minimum operating voltage or else unreliable behaviour may occur.
The brownout voltage is fixed for each device as follows:
||20X2, 14M2, 18M2, 20M2, 28X2, 40X2
||08, 08M, 14M, 20M, 28X1, 40X1
||18, 18A, 18M, 18X, 28A, 28X, 40X