1. Article purpose[edit source]
The purpose of this article is to:
- briefly introduce the STM 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 STM peripheral.
2. Peripheral overview[edit source]
The STM peripheral is used to log STM traces into the embedded trace FIFO (ETF). This trace can include hardware events (the list is given in the STM32MP15 reference manuals) or direct 'printf like' log from the Cortex®-A7. Once in the ETF buffer, the trace can be dumped directly from the Cortex®-A7 or to the trace port interface unit (TPIU), connected to an external probe able to decode it.
2.1. Features[edit source]
Refer to the STM32MP15 reference manuals for the complete list of features, and to the software components, introduced below, to see which features are really implemented.
2.2. Security support[edit source]
The STM is a non secure peripheral.
3. Peripheral usage and associated software[edit source]
3.1. Boot time[edit source]
The STM can be used to debug the boot sequence using an external probe, without any associated embedded software.
3.2. Runtime[edit source]
3.2.1. Overview[edit source]
The STM can be used to debug the run time application using an external probe, without any associated embedded software.
3.2.2. Software frameworks[edit source]
There is no software dedicated to the STM internal peripheral delivered with the STM32 MPU ecosystem but the STM trace can be captured using an external probe.
3.2.3. Peripheral configuration[edit source]
Configuration of the STM is done via JTAG scripts. Those scripts must be built by the user using the STM32MP15 reference manuals .
3.2.4. Peripheral assignment[edit source]
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 a runtime 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 STM32MP15 reference manuals.
| Domain | Peripheral | Runtime allocation | Comment | |||
|---|---|---|---|---|---|---|
| Instance | Cortex-A7 secure (OP-TEE) |
Cortex-A7 non-secure (Linux) |
Cortex-M4 (STM32Cube) | |||
| Trace & Debug | STM | STM | No assignment possible | |||