NCV7748GEVB
www.onsemi.com
5
OPERATIONAL GUIDELINES
The material necessary to successfully use the evaluation
board is listed below.
•
NCV7748 Evaluation Board
•
14 V Power Supply Capable of Drive 1 A
Configure the Board
Typical Board Configuration with On-board Components
1. Connect all jumpers on the board with the
exception of the LOOP jumper (J9) for output
control. This jumper is located directly next to the
OUTPUT CONTROL pushbutton.
2. Set the DEMO MODE toggle switch OFF.
Demo Mode
1. Configure the board as per above.
2. Connect the 14 V power supply.
3. Turn on the power supply.
4. The splash screen will be shown (see Figure 6).
5. Move the DEMO MODE toggle switch to the ON
position.
Figure 6. Splash Screen
At this point, the relays will individually sequence from
OUT1 to OUT8 and repeat. This is indicated on the board
with the illumination of the LEDs connected to the outputs
of the relays. Figure 7 shows the board when OUT2 is
illuminated. This will continue indefinitely. Switching the
demo mode toggle switch off, the sequence will continue
and stop on OUT8 until the NCV7748 device times out and
OUT8 will also turn off.
Figure 7. Sequencing Demo Mode
Normal Operation
1. Move the DEMO MODE toggle switch to the OFF
mode.
2. This sets the NCV7748 ready to receive LIN
commands from the on-board microprocessor.
3. Set the DIP switches using the OUTPUT
CONTROL COMMAND for DATA 1 and
DATA 2 for the targeted outputs and the OUTPUT
ENCODING for the output state. In this mode,
DATA 3 will always display all zeros.
4. Press the OUTPUT CONTROL pushbutton
(Figure 9) located to the left of the DIP switches.
5. The selected outputs will turn on.
NOTE: Figure 8 displays the setup for all 8
outputs to turn on.
NOTE: Figure 12 highlights the dip switches
settings and the resultant display of the settings.
All selected outputs will remain illuminated until
the NCV7748 sleep timer has expired. This is
indicative of no communication on the LIN bus.
When the sleep timer expires, all outputs will turn
off. When in sleep mode, a GET STATUS
command will display “Sleep Mode”. All 1’s are
displayed (Figure 10) because the bus is recessive
in sleep mode.
6. To circumvent the sleep timer and maintain
a continuous output state, connect the jumper
(LOOP) next to the OUTPUT CONTROL
pushbutton (see Figure 9). This will repeatedly
send LIN commands. As a result the device will
not go to sleep. DIP switch activity is allowed with
the loop jumper connected. This allows for real
time switching selection of the output drivers.
