C167CS datasheet(375/517 Pages) INFINEON

375 / 517 page

C167CS

Derivatives

The On-Chip CAN Interface

User’s Manual

19-3

V2.0, 2000-07

19.1

Functional Blocks of the CAN Module

The CAN module combines several functional blocks (see Figure 19-2) that work in

parallel and contribute to the controller’s performance. These units and the functions

they provide are described below.

Each of the message objects has a unique identifier and its own set of control and status

bits. Each object can be configured with its direction as either transmit or receive, except

the last message which is only a double receive buffer with a special mask register.

An object with its direction set as transmit can be configured to be automatically sent

whenever a remote frame with a matching identifier (taking into account the respective

global mask register) is received over the CAN bus. By requesting the transmission of a

message with the direction set as receive, a remote frame can be sent to request that

the appropriate object be sent by some other node. Each object has separate transmit

and receive interrupts and status bits, giving the CPU full flexibility in detecting when a

remote/data frame has been sent or received.

For general purpose two masks for acceptance filtering can be programmed, one for

identifiers of 11 bits and one for identifiers of 29 bits. However the CPU must configure

bit XTD (Normal or Extended Frame Identifier) for each valid message to determine

whether a standard or extended frame will be accepted.

The last message object has its own programmable mask for acceptance filtering,

allowing a large number of infrequent objects to be handled by the system.

The object layer architecture of the CAN controller is designed to be as regular and

orthogonal as possible. This makes it easy to use.

C167CS Datasheet(PDF) 375 Page - Infineon Technologies AG