NCV7748GEVB
www.onsemi.com
7
GET STATUS
To retrieve the outputs status including the state of the
output and any information stored in the error field and
APPINFO registers, simply press the GET STATUS button
located directly below the OUTPUT CONTROL button.
Note, if you have the LOOP jumper connected, the GET
STATUS information will only be displayed while the
button is depressed. Remove the LOOP jumper if
a continuous display of error information is desired.
All zeros in the ERR and APPINFO register are indicative
of normal operation with no issues.
Errors which can be detected on this board include:
ERR
1. No Error.
2. Reset. A reset error will be displayed with VBB
por.
3. Byte Field Framing Error. An error can be seen
here when there is conflict on the bus such as
when two opposing signals are sent from DEMO
MODE and OUTPUT CONTROL followed by
a GET STATUS command.
To see this error:
a. Put the toggle switch in demo mode.
b. While in demo mode, press the output
control pushbutton.
c. Release the output control pushbutton.
d. Leave demo mode using the toggle switch
before OUT8 turns on.
e. Press the Get Status pushbutton. Multiple
attempts may be required to see this result.
Figure 13. Byte Field Framing Error
APPINFO
4. No Failure.
5. Global Thermal Shutdown*.
6. OUT4/OUT8 Overcurrent or Thermal Shutdown*.
a. Overcurrent setups are created with the
individual OCD (1−8) pushbuttons. Only
OUT4 and OUT8 are reported in the
APPINFO register by design.
b. Overcurrent is also reported in the output
status readout (Figure 14). This is a latched
off event. A successful turn-off command
must be sent before an output in an OCD
condition will turn back on.
* Thermal Shutdown events are not advised on this board due to the
potential damage.
Figure 14. Output Status and Error Reporting Decoding
Open Load
Open load conditions are reported in the status reporting
for OUT4 and OUT8. Jumpers labeled Load 1–Load 8 are
included on the board. Figure 14 shows how open load faults
are reported in the OUT STATUS READOUT. These are
reported in the output off state.
External LIN Communication
The NCV7748GEVB uses an NCV7321 LIN transceiver
for communication from the microprocessor to the LIN bus
pin of the NCV7748 device. Jumpers are include for the TxD
and RxD pins with and adjacent LIN connection pin
providing the user with flexibility for an external LIN based
master device.
Additionally an RJ11 connector provides an alternative
for a connection to the LIN bus with a connection to VBB,
and ground.
