ST STM8S Reference Manual

RM0016 Controller area network (beCAN)
Doc ID 14587 Rev 8 363/449
23.3 beCAN general description
In today’s CAN applications, the number of nodes in a network is increasing and often
several networks are linked together via gateways. Typically the number of messages in the
system (and thus to be handled by each node) has significantly increased. In addition to the
application messages, Network Management and Diagnostic messages have been
introduced.
● An enhanced filtering mechanism is required to handle each type of message.
Furthermore, application tasks require more CPU time, therefore real-time constraints
caused by message reception have to be reduced.
● A receive FIFO scheme allows the CPU to be dedicated to application tasks for a long
time period without losing messages.
The standard HLP (Higher Layer Protocol) based on standard CAN drivers requires an
efficient interface to the CAN controller.
● All mailboxes and registers are organized in 16-byte pages mapped at the same
address and selected via a page select register.
Figure 139. CAN network topology
23.3.1 CAN 2.0B active core
The beCAN module handles the transmission and the reception of CAN messages fully
autonomously. Standard identifiers (11-bit) and extended identifiers (29-bit) are fully
supported by hardware.
23.3.2 Control, status and configuration registers
The application uses these registers to:
● Configure CAN parameters, e.g. baud rate
● Request transmissions
● Handle receptions
● Manage interrupts
● Get diagnostic information
CAN node 1
CAN node 2 CAN node n
CANCAN
High
Low
CANCAN
Rx Tx
CAN
Transceiver
CAN
Controller
STM8 MCU
CAN Bus
Application

ST STM8S Specifications

General

Brand	ST
Model	STM8S
Category	Microcontrollers
Language	English