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), M
1
-ATX constantly monitors the battery levels. When battery level
drops below 11V for more than one minute, M
1
-ATX will shut down and re-activate only
when the input voltage is > 11V.
Engine Cranks, under-voltage and over-voltage situations
. Another difficult task is
maintaining stable 3.3V, 5V, 12V and -12V power to your PC. While car batteries are
rated at 12V, they actually provide voltages in between 7-11V (engine cranks) or as high
as 80 volts (load dump). Most of the times, your battery will stay at 13.5V (while car is
running) but extra precautions need to take place in order to prevent such situations. M
1
-
ATX can operate as low as 6V and as high as 28V while providing strict regulation on all
rails along with input voltage clamping and reverse protection.
Loud amplifier pops when PC starts.
If your PC is connected to your car amplifier, you
will hear a loud pop when the computer is first started. The M
1
-ATX has an ‘anti-thump’
control that will keep your amp OFF while the PC starts. Simply connect J6 to your
amplifier remote control pins to activate the ‘anti-thump’ feature.
2.0
Mode of operation
The M
1
-ATX performs several timing routines and takes actions as follows:
(
NOTE
: When all config jumpers are removed, M
1
-ATX will be in the “dumb PSU mode”,
no ignition timing, no HARDOFF. M
1
-ATX will send a gratuitous “ON” pulse to the M/B
when power is applied for the first time. Do not connect J8/J9 to the M/B on/off switch if
you don’t want your PC to be started automatically.
1)
Ignition=OFF. Nothing happens. M2-ATX is waiting for ignition signals.
2)
Ignition=ON. M2-ATX waits for 2-3 seconds then turns on the 5Vsb rail. After another second M2-ATX
sends an “ON” signal to the motherboard via the 2 wires connected to the motherboard’s ON/OFF pins.
The motherboard will turn ON and your system should start booting.
3)
Ignition=ON during driving. Your computer will remain ON.
4)
Ignition=OFF. M2-ATX waits for “OFFDELAY” in seconds (see jumper chart on Page 2) and then it turns
the motherboard OFF by sending a signal to the motherboard’s ON/OFF switch. Your computer should
turn off gracefully (shutdown procedure). During this time, power will still be available for your PC to
perform shutdown.
5)
5VSB will still be provided for another “HARDOFF” seconds (see jumper chart). In the event where the
shutdown process is longer than “OFFDELAY” (windows gets frozen, etc), power will be shut down hard,
turning off all power rails. If “HARDOFF” is set to ‘NEVER”, the PSU will always provide 5VSB, therefore
the PC can also be used in the SLEEP mode. During the HARDOFF procedure, the battery levels will be
constantly monitored to prevent deep discharge situations.
6)
M
1
-ATX will go to step 1, if ignition is tuned ON again.
3.0 Troubleshooting
a) Motherboard is not turning ON.
M2-ATX User Guide Page 3
