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.
*
AutoLatch
is active during the fist 60s of PC operation (and only during the first 60 seconds). For example, If Ignition is
turned ON and then OFF right away, M1-ATX will latch Ignition in ON position for the next 60 seconds, allowing your
operating system to fully come up. This will prevent disk drive corruption or systems that remain hung in the ON position.
After the first 60 seconds of system operation, the AutoLatch feature will be removed and system will shut down at as
governed by the “Off-delay” setting.
1.3 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.
The M2-ATX is addressing these issues by cutting off the 5VSB rail after a pre-defined amount of time (see jumper chart,
HARDOFF). When 5VSB is always active (HARDOFF=Never), M2-ATX constantly monitors the battery levels. When battery
level drops below 11V for more than one minute, M2-ATX will shut down and re-activate only when the input voltage is >
11V.
