TM8000 3DK Hardware Developer’s Kit
Application Manual
Power Sense Options
125
September 2003
© Tait Electronics Ltd
7.4
No Power Sense (On/Off Key Only)
With this option, the on/off key is the only way to power up the radio.
Use this option, when the ‘auxiliary’ or ‘internal options power sense’
options are not required and when it is not important if the radio does not
power up when the radio is initially connected to power. The advantage of
this option over ‘13.8V battery power sense’ is that the radio draws < 1mA
when off.
Application
Use this option, when the radio needs to respond only to control head key
presses, the radio must always be off when power is applied, and use minimal
power when off.
7.5
Emergency Power Sense
Emergency control is usually installed in situations where the radio user
could be in possible danger (e.g. taxis, armoured vehicles, police etc.) or
where there could be a medical emergency (e.g. buses etc.). An emergency
call or programmable key press can activate emergency mode. As a
programmable option, emergency mode can also be activated by pressing a
hidden emergency button for two seconds.
‘Emergency power sense’ uses the AUX_GPI2 line of the auxiliary
connector and is connected to the power-up circuitry via hardware link
LK3. This line is active low
≤
0.7V and has an internal pull-up to the radio
supply voltage. Activation of ‘emergency power sense’ will power up the
radio and enter the emergency mode.
Note
The emergency mode can also be entered through the input lines
of the internal options connector, however these input lines do
not use ‘emergency power sense’ and the radio will not be pow-
ered up.
For more information on the emergency mode see the online help of the
programming application.
