CEC internal peripheral

Revision as of 15:25, 26 October 2021 by Gerald Baeza (talk | contribs) (Article purpose)
Applicable for STM32MP15x lines

1 Article purpose[edit]

The purpose of this article is to:

  • briefly introduce the CEC 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 CEC peripheral.

2 Peripheral overview[edit]

The CEC (consumer electronics control) or HDMI-CEC is an STM32 internal peripheral that allows to receive/send messages from/to devices, such as TV or tuner, through a HDMI cable.

2.1 Features[edit]

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

Refer to the STM32 CEC presentation [1] for an overview of the CEC hardware block capabilities.

2.2 Security support[edit]

The CEC is a non-secure peripheral.

3 Peripheral usage and associated software[edit]

3.1 Boot time[edit]

The CEC is not used at boot time.

3.2 Runtime[edit]

3.2.1 Overview[edit]

The CEC internal peripheral can be allocated to:

  • the Arm® Cortex®-A7 non-secure core to be controlled in Linux® by the CEC framework


Chapter Peripheral assignment describes which peripheral instance can be assigned to which context.

3.2.2 Software frameworks[edit]

Internal peripherals software table template

| Low-speed interface
| CEC framework
| CEC HAL 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 or for Linux® in the CEC device tree configuration article.

3.2.4 Peripheral assignment[edit]

Internal peripherals assignment table template

| rowspan="1" | Visual
| rowspan="1" | CEC
| Assignment (single choice)

4 How to go further[edit]

Refer to the STM32 CEC application note (AN4066) [2] for a detailed description of the CEC peripheral and applicable use-cases.

Even if this application note is related to STM32 microcontrollers, it also applies to STM32 MPUs.

5 References[edit]