MPC555
/
MPC556
CAN 2.0B CONTROLLER MODULE
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
16-3
Figure 16-2 Typical CAN Network
Each CAN station is connected physically to the CAN bus through a transceiver. The
transceiver provides the transmit drive, waveshaping, and receive/compare functions
required for communicating on the CAN bus. It can also provide protection against
damage to the TouCAN caused by a defective CAN bus or a defective CAN station.
16.3 TouCAN Architecture
The TouCAN module uses a flexible design that allows each of its 16 message buffers
to be designated either a transmit (Tx) buffer or a receive (Rx) buffer. In addition, to
reduce the CPU overhead required for message handling, each message buffer is as-
signed an interrupt flag bit to indicate that the transmission or reception completed
successfully.
16.3.1 TX/RX Message Buffer Structure
displays the extended (29-bit) ID message buffer structure.
displays the standard (11-bit) ID message buffer structure.
TRANSCEIVER
……
CNTX0
CNRX0
CAN
CONTROLLER
(TouCAN)
CAN SYSTEM
CAN STATION 2
CAN STATION n
CAN STATION 1
CNTX1
1
CNRX1
1
1. In the MPC555, the CNTX1 and CNRX1 signals are not available.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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