CAN Interface
MOTOROLA Technical Summary 2-19
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 Table 2-13. The CANH
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 Table 2-13 for the CAN connector signals and to
Figure 2-10 for a connection diagram.
Figure 2-10. CAN Interface
.
Table 2-12. CAN Signal Isolation Jumper Options
JG15
Pin # Signal Pin # Signal
1 CAN_TX 2 CAN_TX to CAN Transceiver
3 CAN_RX 4 CAN_RX from CAN Transceiver
56F8323
+5.0V
CAN Transceiver
J12
Daisy Chain CAN
Connector
J13
CAN Bus
Connector
CAN Bus
Terminator
JG10
120
PCA82C250T
1K
CAN_TX
CAN_RX
1
2
3
4
5
4
3
5
CANH
CANL
TXD
RXD
JG15
1
3
4
2
Frees
cale Semiconductor,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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