SN65HVD257 EVM Configuration for Two Independent Networks
4
SN65HVD257 EVM Configuration for Two Independent Networks
This section describes how to reconfigure the EVM into two independent networks. With this configuration,
the EVM could be used to host two node physical layers. The sections of the EVM not specifically
described below such as termination, filtering and protection are used in the same or similar fashion as
when the EVM is configured for a redundant network.
4.1
Transceiver 1 Header (JMP3)
4.1.1
TXD1 Input (JMP3, TP5)
The TXD1 input on JMP3 connects to transceiver 1 (U1) and TP5. To reconfigure the EVM, R8 must be
removed to disconnect TXDprime from U1, and R4 must be installed with a 0
Ω
resistor or current limiting
serial resistor of choice for the application to route the TXD1 signal to U1.
4.1.2
RXD1 Output (JMP3, TP8)
The RXD1 output of transceiver 1 (U1) is routed to JMP3 and TP8. If no parasitic loading to the combining
AND gate U2 is desired, then R17 may be removed.
4.1.3
S1 Input (Mode Selection,) (JMP3, JMP2 and TP6)
Pin 8 of the transceiver is the mode control pin of the device. Pin 8 of transceiver 1 is routed to JMP3,
JMP2 and TP6.
MODE SELECTION OPTIONS
JMP3, transceiver 1 header configuration:
Header JMP3 handles all the digital IO signals for transceiver 1. JMP3 may be used to route these
signals to an external host processor or test system. Make sure that the MODE (JMP2) jumper
settings are not conflicting with signals to JMP3.
JMP2, transceiver 1 configuration (3 way jumper):
If the header is not used, then JMP2 may be used to configure the S pin (pin 8) of transceiver 1 to
a pull up to V
CC
(Silent Mode) or pull down to GND (Normal Mode).
TP6, transceiver 1 configuration:
This test point connects directly to the S pin (pin 8) of transceiver 1. Ensure that JMP3 and JMP2
are not configured to conflict if TP3 is used as the input connection.
4.1.4
FLT1 Output (JMP3, TP10)
Pin 5 of transceiver 1 is the fault output of the transceiver. This output routes to JMP3 and TP10. This
output indicates a RXD DTO, TXD DTO, Thermal Shut Down or undervoltage fault with transceiver 1.
4.2
Transceiver 2 Header (JMP7)
4.2.1
TXD2 Input (JMP7, TP18)
The TXD2 input on JMP7 is connected to transceiver 2 (U5) and TP5. To reconfigure the EVM, R32 must
be removed to disconnect TXDprime from U5, and R28 must be installed with a 0
Ω
resistor or current
limiting serial resistor of choice for the application to route the TXD2 signal to U5.
4.2.2
RXD2 Output (JMP7, TP21)
The RXD2 output of transceiver 2 (U5) is routed to JMP7 and TP21. If no parasitic loading to the
combining AND gate U2 is desired, then R21 may be removed.
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SN65HVD257 CAN EVM: Functional Safety and Redundant CAN Network
SLLU172 – August 2012
Copyright © 2012, Texas Instruments Incorporated
