Husky MP2500 Manual page 326

32.1.2.1 Power-down key
Pressing the P key will normally turn MP2500 off, but this can be
prevented by using INT 15H function 69H. (This function also prevents
power down by the power-down function and idle timeout.)
32.1.2.2 Low power
The MP2500 power management system monitors the battery voltage. If
this falls below approximately 3.3V the MP2500 will display low power
warning messages. If the voltage goes lower the unit will power off.
32.1.2.3 Idle timeout
To conserve power, MP2500 will normally turn off automatically if left idle
(no keyboard input or communications activity) for 5 minutes. When the
user is ready to continue, he or she can simply press P to carry on as if
nothing had happened.
You can change the timeout period (or disable it entirely) by using INT 15H
function 63H. You can prevent the power down by using INT 15H function
69H (which also prevents power down due to the power-down key or
function).
32.1.2.4 Power-down function
The power down function (INT 15H function 68H) can be used to turn off
MP2500. Use it, for example, to save power when a task is complete or to
wait for the RTC alarm or an incoming call to turn it on (see section 32.1.1).
This function can be disabled by INT 15H function 69H.
32.1.2.5 Controlling power-down causes
INT 15H function 69H will prevent power-down due to the idle timeout,
power-down key or power-down function. Use it, for example, to make sure
that the current task is completed before power-down.
Note that this function cannot prevent power-down due to low power (see
section 32.1.2.2) or loss of power.
304 H MP2500 System Developer's Guide
USKY