Input 11: Vbatt Low
Analog to Digital Inputs
A/D 0: External Power Supply Monitor
A/D 1: External A/D Input (From Power Connector)
A/D 2: External A/D Input (From 22 Pin I/O Conenctor)
A/D 3: External A/D Input (From 22 Pin I/O Conenctor)
A/D 4: External A/D Input (From 22 Pin I/O Conenctor)
A/D 5: External A/D Input (From 22 Pin I/O Conenctor)
A/D 6: Internal Battery Voltage
A/D 7: GPS Antenna Voltage
Outputs:
Output 0: Standard Open Collector Relay Output
Output 1: Standard Open Collector Relay Output
Output 2: Standard Open Collector Relay Output
Output 3: Standard Open Collector Relay Output
Output 4: Standard Open Collector Relay Output
Output 5: LED Driver Output 1
Output 6: LED Driver Output 2
iButton / 1 Bit Bus
iButton ID Support
1Wire bus with current boost for temperature sensors
3.5.1 Ignition and Inputs
The LMU-5541
™
provides up to 7 High/low selectable inputs and one Ignition Sense input.. These inputs are protected from typical vehicle
transients and can be directly connected to most vehicle level logical inputs from
4 volts up to the vehicle power input level (typically 12 VDC). Their input impedance is approximately 10k . One of these inputs is dedicated to
sensing the vehicle’s ignition status to provide for flexible power
management. The other seven inputs may be used to sense vehicle inputs such as cooling unit operation, a hidden driver “Panic” switch, taxi on-
duty/off-duty meter status or many others.
The ignition input is pulled to ground through the 10k resistance, where the other inputs can be configured to be normally High (i.e. pulled to
+12v through a 200K10k resistor) or Low (i.e. pulled to ground through a
100K10k resistor). The diagrams below show how to connect the inputs in both a high- and low-biased configuration:
LMU-5541 Hardware & Installation Guide
12/49
Sample Input Wiring
3.5.2 Open Collector Outputs
The LMU’s outputs are designed to drive external relays. These outputs provide a high-current, open-collector driver that can sink up to 200 mA
each. These drivers may be used to drive external relays that can then control
vehicle functions such as door locks, fuel shut-off valves, sirens and lights. If additional current is required to drive the relays, external circuitry
can be added to source the current. This diagram is a typical use of an output
to drive a relay.
LMU-5541 Hardware & Installation Guide
13/49
Sample Relay Wiring
3.5.3 LED Outputs
The LMUs 2 LED outputs are designed specifically to control external LEDs. The LED outputs have two states. When on, they provide 3.3V to
the external connector through a 100ohm series resistor. When off, these
outputs are high impedance
3.5.4 Status LEDs
The LMU-5541
™
is equipped with five Status LEDs; Power, BT, WiFi, GPS, COMM (wireless network). The LEDs use the following blink
patterns to indicate service:
LED #1 (Power LED - Red/Green) Definitions
Condition LED 1
LMU Off Off
U-Boot Red Solid
Kernel Start Green Solid
LMU On Red Solid
LED #2 (BT LED - Red/Green) Definitions
Condition LED 2
U-Boot Red Solid
Kernel Start Green Solid
BT Off No LED indication by default
BT On No LED indication by default
BT Connected No LED indication by default
Customer can define their own BT LED pattern by :
for Bluetooth LED Green :
echo 1 > /sys/class/gpio/gpio184/value
for Bluetooth LED Red:
LMU-5541 Hardware & Installation Guide
14/49
echo 1 > /sys/class/gpio/gpio185/value
