Controller area network (bxCAN) RM0008
500/690
Management
● Maskable interrupts
● Software-efficient mailbox mapping at a unique address space
Note: The USB and CAN share a dedicated 512-byte SRAM memory for data transmission and
reception, and so they cannot be used concurrently (the shared SRAM is accessed through
CAN and USB exclusively). The USB and CAN can be used in the same application but not
at the same time.
21.2.1 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.
Figure 191. CAN network topology
CAN 2.0B active core
The bxCAN 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.
CAN node 1
CAN node 2
CAN node n
CANCAN
High
Low
CANCAN
Rx Tx
CAN
Transceiver
CAN
Controller
MCU
CAN Bus
Application
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