MC68HC05X4 Datasheet, PDF (75/156 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Freescale Semiconductor, Inc.
Motorola CAN
Interface to the MC68HC05X4 CPU
known, until after the first byte has been stored, whether or not the
transmitting node will lose arbitration to another node.
Interface to the MC68HC05X4 CPU
The MCAN handles all the communication transactions flowing across
the serial bus. For example, the CPU merely places a message to be
transmitted into the transmit buffer and sets the TR bit. The MCAN will
begin transmitting the message when it has determined that the bus is
idle. In the event of a transmission error, the MCAN will initiate a
repeated transmission automatically.
In a similar manner, the CPU module is notified that a message has been
received only if it was error free. If any error occurs, the MCAN signals
the error within the CAN protocol without CPU intervention.
The MCAN within the MC68HC05X4 is controlled using a block of 30
registers. This comprises 10 control registers, 10 Transmit buffer
registers and 10 receive buffer registers. These registers are memory
mapped between $20 and $3D (see Figure 3).
NOTE:
There is an offset of $20 between the MC68HC05X4 addresses and the
MCAN internal addresses, i.e. MCAN addresses $00 to $1D, as defined
in the BOSCH CAN specification, are mapped to MC68HC05X4
addresses $20 to $3D.
7-mcan
MOTOROLA
Motorola CAN
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MC68HC05X4 Rev 1.0
75