FDCAN internal peripheral

Revision as of 17:48, 2 December 2021 by Registered User

Applicable for STM32MP13x lines, STM32MP15x lines

1 Article purpose[edit]

The purpose of this article is to:

  • briefly introduce the FDCAN peripheral and its main features
  • indicate the level of security supported by this hardware block
  • explain how each instance can be allocated to the runtime contexts and linked to the corresponding software components
  • explain, when necessary, how to configure the FDCAN peripheral.

2 Peripheral overview[edit]

FDCAN peripheral handles data communication in a Controller Area Network (CAN) bus system using message-based protocol originally designed for in-vehicle communication. The CAN subsystem consists of two CAN modules (FDCAN1 and FDCAN2), a shared message RAM and an optional clock calibration unit.

2.1 Features[edit]

Both FDCAN instances are compliant with classic CAN protocol[1] and CAN FD[2] (CAN with Flexible Data-Rate) protocol. In addition, FDCAN1 supports time triggered CAN (TTCAN).

FDCAN1 and FDCAN2 share a dedicated 10 Kbyte CAN SRAM for message transfers.

Refer to STM32MP13 reference manuals or STM32MP15 reference manuals for the complete list of features, and to the software components, introduced below, to see which features are implemented.

2.2 Security support[edit]

FDCAN is a non secure peripheral.

3 Peripheral usage and associated software[edit]

3.1 Boot time[edit]

The FDCAN is not used at boot time.

3.2 Runtime[edit]

3.2.1 Overview[edit]

FDCAN instances can be allocated to:

  • the Arm® Cortex®-A7 non-secure core to be controlled in Linux® by the NetDev framework (See CAN overview)

or, on STM32MP15x lines More info.png only

3.2.2 Software frameworks[edit] On STM32MP13x lines More info.png[edit]
Domain Peripheral Software components Comment
OP-TEE Linux
Networking FDCAN Linux net/can framework On STM32MP15x lines More info.png[edit]

Internal peripherals software table template

| Networking
| Linux net/can framework
| STM32Cube FDCAN driver

3.2.3 Peripheral configuration[edit]

The configuration is applied by the firmware running in the context to which the peripheral is assigned. The configuration can be done alone via the STM32CubeMX tool for all internal peripherals, and then manually completed (particularly for external peripherals) according to the information given in the corresponding software framework article. When the FDCAN peripheral is assigned to the Linux® OS, it is configured through the device tree according to the information given in the FDCAN device tree configuration article.

3.2.4 Peripheral assignment[edit] On STM32MP13x lines More info.png[edit]

Click on the right to expand the legend...


Check boxes illustrate the possible peripheral allocations supported by STM32 MPU Embedded Software:

  • means that the peripheral can be assigned () to the given runtime context.
  • means that the peripheral can be assigned to the given runtime context, but this configuration is not supported in STM32 MPU Embedded Software distribution.
  • is used for system peripherals that cannot be unchecked because they are statically connected in the device.

Refer to How to assign an internal peripheral to an execution context for more information on how to assign peripherals manually or via STM32CubeMX.
The present chapter describes STMicroelectronics recommendations or choice of implementation. Additional possiblities might be described in STM32MP13 reference manuals.

Domain Peripheral Runtime allocation Comment
Instance Cortex-A7
Networking FDCAN FDCAN1
FDCAN2 On STM32MP15x lines More info.png[edit]

Internal peripherals assignment table template

| rowspan="2" | Networking
| rowspan="2" | FDCAN
| Assignment (single choice)
| Assignment (single choice)


4 References[edit]

  1. CAN protocol implementations, from the CAN in Automation group (CiA)
  2. CAN FD - The basic idea, from the CAN in Automation group (CiA)