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M0A21/M0A23 Series
May 06, 2022
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Rev 1.02
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ANUAL
6.16 Controller Area Network (CAN)
6.16.1 Overview
The Bosch CAN (is named as C_CAN) consists of the CAN Core, Message RAM, Message Handler,
Control Registers and Module Interface. The CAN Core performs communication according to the CAN
protocol version 2.0 part A and B. The bit rate can be programmed to values up to 1 MBit/s. For the
connection to the physical layer, additional transceiver hardware is required.
For communication on a CAN network, individual Message Objects are configured. The Message
Objects and Identifier Masks for acceptance filtering of received messages are stored in the Message
RAM. All functions concerning the handling of messages are implemented in the Message Handler.
These functions include acceptance filtering, the transfer of messages between the CAN Core and the
Message RAM, and the handling of transmission requests as well as the generation of the module
interrupt.
The register set of the C_CAN can be accessed directly by the software through the module interface.
These registers are used to control/configure the CAN Core and the Message Handler and to access
the Message RAM.
6.16.2 Features
Supports CAN protocol version 2.0 part A and B
Bit rates up to 1 MBit/s
32 Message Objects
Each Message Object has its own identifier mask
Programmable FIFO mode (concatenation of Message Objects)
Maskable interrupt
Disabled Automatic Re-transmission mode for Time Triggered CAN applications
Programmable loop-back mode for self-test operation
16-bit module interfaces to the AMBA APB bus
Supports wake-up function
6.16.3 Block Diagram
The C_CAN interfaces with the AMBA APB bus. Figure 6.16-1 shows the block diagram of the C_CAN.
CAN Core
–
CAN Protocol Controller and Rx/Tx Shift Register for serial/parallel conversion of
messages.
Message RAM
–
Stores Message Objects and Identifier Masks
Registers
–
All registers used to control and to configure the C_CAN.
–
Message Handler
–
State Machine that controls the data transfer between the Rx/Tx Shift Register of the
CAN Core and the Message RAM as well as the generation of interrupts as
programmed in the Control and Configuration Registers.
Module Interface