MEGA128CAN Datasheet, PDF (234/413 Pages) ATMEL Corporation – Microcontroller WITH 128K BYTES OF ISP FLASH AND CAN CONTROLLER

CAN Controller
The CAN controller implemented into AT90CAN128 offers V2.0B Active.
This full-CAN controller provides the whole hardware for convenient acceptance filtering
and message management. For each message to be transmitted or received this mod-
ule contains one so called message object in which all information regarding the
message (e.g. identifier, data bytes etc.) are stored.
During the initialization of the peripheral, the application defines which messages are to
be sent and which are to be received. Only if the CAN controller receives a message
whose identifier matches with one of the identifiers of the programmed (receive-) mes-
sage objects the message is stored and the application is informed by interrupt. Another
advantage is that incoming remote frames can be answered automatically by the full-
CAN controller with the corresponding data frame. In this way, the CPU load is strongly
reduced compared to a basic-CAN solution.
Using full-CAN controller, high baudrates and high bus loads with many messages can
be handled.
Figure 115. CAN Controller Structure
Buffer MOb14
Buffer MOb2
Buffer MOb1
Buffer MOb0
CAN Data Buffers
Control
Status
IDtag+IDmask
Time Stamp
Low priority
MOb14
MOb
Scanning
Control
Status
IDtag+IDmask
Time Stamp
MOb2
Control
Status
IDtag+IDmask
Time Stamp
MOb1
Gen. Control
Gen. Status
Enable MOb
Interrupt
Bit Timing
Line Error
CAN Timer
LCC
MAC
PLS
CAN Channel
Control
Status
IDtag+IDmask
Time Stamp
MOb0
Message Objets
High priority
TxDcan
RxDcan
Mailbox
234 AT90CAN128
4250E–CAN–12/04