NCV7748GEVB
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2
Communication
The NCV7748 utilizes a LIN protocol for all
communication. LIN is a single wire communication
network which utilizes a master/slave configuration. The
NCV7748 is the slave and receives its commands from an
external master device and also reports on the same pin
(LIN) to the master device after a request is made. Figure 4
shows the basic LIN schematic. The LIN bus is driven high
through a 30 k
W
resistor in series with a diode and its read
capability is filtered to an internal RxD comparator.
Figure 4. LIN Controller
−
+
From NAD Register
LIN Address
LIN
VBB
RxD
TxD
Filter
Slope
Control
LIN
Protocol
Handler
To
Control
Block
30 k
W
A table (Table 1) of supported commands of the
NCV7748 is listed below from the NCP7744/D data sheet.
Note the NCV7744 reference is to a sister part which is
comprised of 4 outputs instead of the 8 outputs of the
NCV7748.
Table 1. SUPPORTED LIN COMMANDS
PID[7:0]
Frame Type
Description
Data Length
Spec
Depends on NAD
Output Control
Sets all outputs in one virtual node.
8
N/A
Depends on NAD
Get Node ID
Reads identity of prime device in virtual node.
(In frame slave Response)
8
N/A
Depends on Rconfig
and NAD
Get Status
Reads diagnostics of one device (LS driver).
(In frame slave Response)
8
N/A
0x3C
Targeted Reset
Master Request
Re-initialization of one virtual node.
This includes all devices on the virtual node.
8
J2602−1
0x7D
Targeted Reset
Slave Response
Positive response by prime device.
8
0x3C
Read by Identifier
Master Request
Reads identity of device supplier.
8
LIN2.2
0x7D
Read by Identifier
Slave Response
Successfully processed request.
8
Slave could not process the request.
8
0x3C
Broadcast Reset
Re-initialization of all nodes.
8
J2602−1
0x3C
Goto Sleep
All devices enters Sleep Mode.
8
LIN2.2
