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Chapter 16
CAN 2.0B Controller Module
The MPC533 contains three CAN 2.0B controller modules (TouCAN). Each TouCAN is a
communication controller that implements the Controller Area Network (CAN) protocol,
an asynchronous communications protocol used in automotive and industrial control
systems. It is a high speed (one Mbit/sec), short distance, priority based protocol that can
run over a variety of mediums (for example, fiber optic cable or an unshielded twisted pair
of wires). The TouCAN supports both the standard and extended identifier (ID) message
formats specified in the CAN protocol specification, revision 2.0, part B. The third
TouCAN has its signals muxed with MIOS14 GPIO signals. These signals are configured
as GPIO inputs at reset and must be changed to TouCAN signals in the MIOS before
enabling the TouCAN.
Each TouCAN module contains 16 message buffers that are used for transmit and receive
functions. It also contains message filters, which are used to qualify the received message
IDs when comparing them to the receive buffer identifiers. Figure 16-1 shows a block
diagram of a TouCAN module.
MOTOROLA
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
Control
16 Rx/Tx
Message
16-bit
Buffers
Counter
Slave Bus
Interface Unit
IMB
Figure 16-1. TouCAN Block Diagram
Chapter 16. CAN 2.0B Controller Module
CNTX0
Transmitter
CNRX0
Receiver
16-1
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