MPC555
/
MPC556
CAN 2.0B CONTROLLER MODULE
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
16-20
Figure 16-5 Interrupt levels on IRQ with ILBS
16.7 Programmer’s Model
shows the TouCAN address map. The lowercase “x” appended to each
register name represents “A” or “B” for the TouCAN_A or TouCAN_B module, respec-
tively. Refer to
1.3 MPC555 / MPC556 Address Map
to locate each TouCAN module
in the MPC555 / MPC556 address map.
The column labeled “Access” indicates the privilege level at which the CPU must be
operating to access the register. A designation of “S” indicates that supervisor mode
is required. A designation of “S/U” indicates that the register can be programmed for
either supervisor mode access or unrestricted access.
The address space for each TouCAN module is split, with 128 bytes starting at the
base address, and an extra 256 bytes starting at the base a128. The upper
256 are fully used for the message buffer structures. Of the lower 128 bytes, some are
not used. Registers with bits marked as “reserved” should always be written as logic 0.
Typically, the TouCAN control registers are programmed during system initialization,
before the TouCAN becomes synchronized with the CAN bus. The configuration reg-
isters can be changed after synchronization by halting the TouCAN module. This is
done by setting the HALT bit in the TouCAN module configuration register (CANMCR).
The TouCAN responds by asserting the CANMCR NOTRDY bit. Additionally, the con-
trol registers can be modified while the MCU is in background debug mode.
NOTE
The TouCAN has no hard-wired protection against invalid bit/field
programming within its registers. Specifically, no protection is provid-
ed if the programming does not meet CAN protocol requirements.
IMB3 CLOCK
ILBS [1:0]
IMB3 IRQ [7:0]
IRQ
7:0
00
01
11
10
IRQ
15:8
IRQ
23:16
IRQ
31:24
IRQ
7:0
00
01
11
10
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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