SN65HVD257 EVM Configuration for Two Independent Networks
4.2.3
S2 Input (Mode Selection,) (JMP7, JMP8 and TP19)
Pin 8 of the transceiver is the mode control pin of the device. Pin 8 of transceiver 2 is routed to JMP7,
JMP8 and TP19.
MODE SELECTION OPTIONS
JMP7, transceiver 2 header configuration:
Header JMP7 handles all the digital IO signals for transceiver 2. JMP7 may be used to route the
signals to an external host processor or test system. Ensure that the MODE (JMP8) jumper settings
are not conflicting with signals to JMP7.
JMP8, transceiver 2 configuration (3 way jumper):
If the header is not used, then JMP8 may be used to configure S pin (pin 8) of transceiver 2 to a
pull up to V
CC
(Silent Mode) or pull down to GND (Normal Mode)
TP19, transceiver 2 configuration:
This test point connects directly to the S pin (pin 8) of transceiver 2. Ensure JMP7 and JMP8 are
not configured to conflict if TP19 is used as the input connection.
4.2.4
FLT2 Output (JMP7, TP23)
Pin 5 of transceiver 2 is the fault output of the transceiver. This output routed to JMP7 and TP23. This
output indicates a RXD DTO, TXD DTO, Thermal Shut Down or undervoltage fault with transceiver 2.
4.2.5
Loopback (single bus connection) of the Two Nodes (JMP12 and 13)
The EVM provides a path via JMP12 and JMP13 to connect to two nodes (transceivers) together on the
board as a single CAN network. On node 1 (transceiver 1, U1) connect CANH1 and CANL1 across JMP5
and JMP12 as shown below. On node 2 (transceiver 2, U5) connect CANH2 and CANL2 across JMP10
and JMP13 as shown below. CANH1 is now connected to CANH2 and CANL1 is connected to CANL2 in
one CAN network.
Figure 6. Loopback Node 1 (JMP5 to JMP12)
Figure 7. Loopback Node 2 (JMP10 to JMP13)
13
SLLU172 – August 2012
SN65HVD257 CAN EVM: Functional Safety and Redundant CAN Network
Copyright © 2012, Texas Instruments Incorporated
