Can Interface; Can Signal Isolation Jumper Options - Motorola 56F8323 User Manual

2.12 CAN Interface

The 56F8323EVM board contains a CAN physical-layer interface chip that is attached to
the FlexCAN port's CAN_RX and CAN_TX pins on the 56F8323. The EVM board uses a
Philips high-speed, 1.0Mbps, physical layer interface chip, PCA82C250. Due to the +5.0V
operating voltage of the CAN interface chip, a pull-up to +5.0V is required to level shift
the Transmit Data output line from the 56F8323. The CAN_TX and CAN_RX signals
from the processor can be isolated by the connector at JG15; see
and CANL signals pass through inductors before attaching to the CAN bus connectors. A
primary, J12, and daisy chain, J13, CAN connectors are provided to allow easy
daisy-chaining of CAN devices. CAN bus termination of 120 ohms can be provided by
adding a jumper to JG10. Refer to
for a connection diagram.
Figure 2-10
56F8323
CAN_TX
CAN_RX
.
Table 2-12. CAN Signal Isolation Jumper Options
Pin #
1
3
MOTOROLA
Freescale Semiconductor, Inc.
Table 2-13
+5.0V
1K
CAN Transceiver
JG15
1 2
TXD
CANH
CANL
3
4
RXD
PCA82C250T
Figure 2-10. CAN Interface
JG15
Signal
CAN_TX
CAN_RX
Technical Summary
For More Information On This Product,
Go to: www.freescale.com
Table
for the CAN connector signals and to
J12
4
5
3
J13
4
5
3
JG10
120
Pin # Signal
2 CAN_TX to CAN Transceiver
4 CAN_RX from CAN Transceiver

CAN Interface

2-13. The CANH
CAN Bus
Connector
Daisy Chain CAN
Connector
1
CAN Bus
2 Terminator
2-19