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XC2000 Derivatives
Peripheral Units (Vol. 2 of 2)
Preliminary
20.2
Controller Area Network (MultiCAN) Controller
CAN Functional Description
This section describes the core features of the CAN module.
20.2.1
Conventions and Definitions
Table 20-1 defines constants that are used throughout the MultiCAN specification.
These are fixed values for a given MultiCAN implementation.
Table 20-1
Fixed Module Constants
Constant
Value
Description
n_objects
128
Number of Message Objects
n_objects denotes the total amount of message objects
available.
n_interrupts
16
Number of Interrupt Output Lines
n_interrupts denotes the total number of interrupt outputs
available.
n_pendings
256
Number of Message Pending Bits
n_pendings denotes the number of message pending bits
available. The number of message pending registers is
given by n_pendings/32.
n_lists
8
Number of Lists
n_lists denotes the total number of lists available for
allocation of message number.
n_nodes
5
Number of CAN Nodes Available
n_nodes denotes the total number of CAN nodes
available. As each CAN node has it’s own list in addition
to the list of un-allocated elements, the relation n_nodes <
n_lists is true.
20.2.2
Introduction
The MultiCAN module contains 5 Full-CAN nodes operating independently or
exchanging data and remote frames via a gateway function.Transmission and reception
of CAN frames is handled in accordance to CAN specification V2.0part B (active). Each
CAN node can receive and transmit standard frames with 11-bit identifiers as well as
extended frames with 29-bit identifiers.
20.2.2.1 Feature Overview
All CAN nodes share a common set of message objects, where each message object
may be individually allocated to one of the CAN nodes. Besides serving as a storage
User’s Manual
MultiCAN, V1.7d2
20-4
V1.0, 2007-06