CP3BT23 Datasheet, PDF (94/260 Pages) Texas Instruments – CP3BT23 Reprogrammable Connectivity Processor with Bluetooth and Dual CAN Interfaces

CTX
CANnTX
0
1
CANnRX
Wake-Up
0
1
CRX
CAN CORE
Transceiver Logic
BTL, RX shift, TX shift, CRC
Bit Stream Processor
Error Management Logic
Control
Status
Data
te INTERFACE MANAGEMENT
Interface Management
Processor
Acceptance Filtering
RAM
Control
TX/RX
Message Buffer 0
le Interface Management
Processor
BTL CONFIG
CAN PRESCALER
o _CONTROL
ACCEPTANCE
MASKS
TX/RX
Message Buffer 1
TX/RX
Message Buffer 14
s_{CPU BUS}
b _DS281
Figure 32. CAN Block Diagram
18.2 BASIC CAN CONCEPTS
A CAN master module has the ability to set a specific bit
O ^{This section provides a generic overview of the basic con- called the “remote data request bit” (RTR) in a frame. Such}
cepts of the Controller Area Network (CAN).
a message is also called a “Remote Frame”. It causes an-
other module, either another master or a slave which ac-
The CAN protocol is a message-based protocol that allows _{cepts this remote frame, to transmit a data frame after the}
a total of 2032 (2¹¹ - 16) different messages in the standard _{remote frame has been completed.}
format and 512 million (2²⁹ - 16) different messages in the
extended frame format.
Additional modules can be added to an existing network
without a configuration change. These modules can either
Every CAN Frame is broadcast on the common bus. Each _{perform completely new functions requiring new data, or}
module receives every frame and filters out the frames _{process existing data to perform a new functionality.}
which are not required for the module's task. For example,
if a dashboard sends a request to switch on headlights, the
CAN module responsible for brake lights must not process
this message.
As the CAN network is message oriented, a message can
be used as a variable which is automatically updated by the
controlling processor. If any module cannot process infor-
mation, it can send an overload frame.
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