SN65HVD257 EVM Setup and Operation for Redundant (Parallel Networks)
MODE SELECTION OPTIONS
JMP1 configuration:
Using header JMP1 (which assumes all the digital IO signals), V
CC
, GND are routed to an external
system. Ensure that the MODE (JMP2 and JMP8) jumper settings are not conflicting with signals to
JMP1.
JMP2, transceiver 1 configuration (3 way jumper):
If using separate IO inputs, use JMP2 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).
JMP8, transceiver 2 configuration (3 way jumper):
If using separate IO inputs, use JMP8 to configure the S pin (pin 8) of transceiver 2 to a pull up to
VCC (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 JMP1 and JMP2
are not configured to conflict if TP3 is used as the input connection.
TP19, transceiver 2 configuration:
This test point connects directly to the S pin (pin 8) of transceiver 2. Ensure that JMP1 and JMP8
are not configured to conflict if TP19 is used as the input connection.
3.1.6
FLT 1 (FAULT, pin 5, transceiver 1) (JMP1, TP10)
Pin 5 of transceiver 1 is the fault output of the transceiver. This output is routed to JMP1 and TP10. This
output indicates a RXD DTO, TXD DTO, Thermal Shut Down or undervoltage fault with transceiver 1.
3.1.7
FLT 2 (FAULT, pin 5, transceiver 2) (JMP1, TP23)
Pin 5 of transceiver 2 is the fault output of the transceiver. This output is routed to JMP1 and TP23. This
output indicates a RXD DTO, TXD DTO, Thermal Shut Down or undervoltage fault with transceiver 2.
3.1.8
FLT 3 (bus open fault) (JMP1)
FLT3 is the fault output of the filtered XOR combination of the two transceiver (bus) outputs. FLT3 will
transition any time the two buses do not match, and thus indicate that one of the buses is open. The
output filter of this logic is pre-installed with a cut off frequency of 50kHz to all for large deviations in timing
between 2 parallel buses. This filter could be tuned by the user to match the filtering requirements of the
target application with respect to bit timing and how much reaction time, or “missing” dominant bits the
application requires, the XOR filter output to then show a transition to the monitoring processor.
3.1.9
JMP3 configuration (not used for Redundant Networks):
Using header JMP3 requires EVM reconfiguration for other applications.
3.1.10
JMP7 configuration (not used for Redundant Networks):
Using header JMP7 requires EVM reconfiguration for other applications.
8
SN65HVD257 CAN EVM: Functional Safety and Redundant CAN Network
SLLU172 – August 2012
Copyright © 2012, Texas Instruments Incorporated
