1.2 M
1-
ATX Connection diagram
M2-ATX, top view
Power Input Connectors
J1
B (un-switched battery, positive)
J3
Ignition (switched battery, positive. Can test by connecting it to B)
J4
Battery - (negative)
Controls and Settings
J6
Controls amplifier via remote ON/OFF. Left pin is RMT, Right pin is GND
J8
To motherboard ON/OFF switch
J10
User jumper settings (A,B,C,D)
J9
To external ON/OFF switch (optional, J8 is in parallel with J9)
Power Output Connectors
J2
Optional P4-12V power
J7
ATX power connector (to motherboard)
J5
To LED (optional)
NOTE: “If HARDOFF is set to “never”, M2-ATX will automatically
shut down when battery voltage is below 11.2V for more than 1
minute in order to prevent ‘deep discharge’ situations.
Mode “0” is regular ATX power supply mode, no power sequencing
provided, can be used for non vehicle applications.
Avoid using HARDOFF = Never, can severely discharge your
battery if PC. Suggested modes are: 1, 2, and 4.
1.2 Power challenges in a Vehicle PC
The 5V Standby Problem
: One of most difficult tasks of operating a PC in a vehicle is
power consumption while the computer is OFF. Even when your computer is OFF, it will
still consume about 100mA on the 5V rail. All power supplies provide 5VSB (5V standby)
so that the motherboard can issue at least a PSON signal. When the computer is in the
suspend mode, it will consume even more power, because the RAM needs to be
powered at all times.
No matter how big your battery is, it will eventually drain your battery in a matter of days.
M2-ATX User Guide Page 2
