infineon / mtb-example-psoc6-dual-cpu-ipc-sema

This example demonstrates how to use the inter-processor communication (IPC) driver to implement a semaphore in PSoC 6 MCU. The semaphore is used to lock to control access to a resource shared by the CPUs and synchronize the initialization instructions.

PSoC™ 6 MCU: Dual-CPU IPC semaphore

This code example demonstrates how to use the inter-processor communication (IPC) driver to implement a semaphore in PSoC™ 6 MCU. The semaphore is used as a lock to control access to a resource shared by the CPUs and synchronize the initialization instructions.

See the "PSoC™ 6 MCU dual-CPU development" section in AN215656 – PSoC™ 6 MCU Dual-CPU system design for instructions on how to develop dual-CPU applications.

Overview

In this example, both CPUs in the PSoC™ 6 MCU share the UART hardware block to send messages to the computer. An IPC semaphore controls access to the UART to avoid situations where both CPUs attempt to send messages at the same time. The same IPC semaphore is also used to synchronize the initialization code between the two CPUs. The example provides an option to disable semaphore usage to observe how it affects the system. An LED on the kit indicates whether the semaphore is being used.

View this README on GitHub.

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Requirements

• ModusToolbox™ v3.1 or later (tested with v3.2)
• Board support package (BSP) minimum required version: 4.2.0
• Programming language: C
• Associated parts: All PSoC™ 6 MCU parts, AIROC™ CYW20819 Bluetooth® & Bluetooth® LE SoC, AIROC™ CYW43012 Wi-Fi & Bluetooth® combo chip, AIROC™ CYW4343W Wi-Fi & Bluetooth® combo chip, AIROC™ CYW4373 Wi-Fi & Bluetooth® combo chip, AIROC™ CYW43439 Wi-Fi & Bluetooth® combo chip

Supported toolchains (make variable 'TOOLCHAIN')

• GNU Arm® Embedded Compiler v11.3.1 (GCC_ARM) – Default value of TOOLCHAIN
• Arm® Compiler v6.16 (ARM)
• IAR C/C++ Compiler v9.30.1 (IAR)

Supported kits (make variable 'TARGET')

• PSoC™ 62S2 Wi-Fi Bluetooth® Prototyping Kit (CY8CPROTO-062S2-43439) – Default value of TARGET
• PSoC™ 6 Wi-Fi Bluetooth® Prototyping Kit (CY8CPROTO-062-4343W)
• PSoC™ 6 Wi-Fi Bluetooth® Pioneer Kit (CY8CKIT-062-WIFI-BT)
• PSoC™ 6 Bluetooth® LE Pioneer Kit (CY8CKIT-062-BLE)
• PSoC™ 6 Bluetooth® LE Prototyping Kit (CY8CPROTO-063-BLE)
• PSoC™ 62S2 Wi-Fi Bluetooth® Pioneer Kit (CY8CKIT-062S2-43012)
• PSoC™ 62S1 Wi-Fi Bluetooth® Pioneer Kit (CYW9P62S1-43438EVB-01)
• PSoC™ 62S1 Wi-Fi Bluetooth® Pioneer Kit (CYW9P62S1-43012EVB-01)
• PSoC™ 62S3 Wi-Fi Bluetooth® Prototyping Kit (CY8CPROTO-062S3-4343W)
• PSoC™ 62S4 Pioneer Kit (CY8CKIT-062S4)
• PSoC™ 62S2 Evaluation Kit (CY8CEVAL-062S2, CY8CEVAL-062S2-LAI-4373M2, CY8CEVAL-062S2-MUR-43439M2, CY8CEVAL-062S2-LAI-43439M2, CY8CEVAL-062S2-MUR-4373EM2, CY8CEVAL-062S2-MUR-4373M2)
• PSoC™ 62S3 Wi-Fi Bluetooth® Prototyping Kit (CYBLE-416045-EVAL)

Hardware setup

This example uses the board's default configuration. See the kit user guide to ensure that the board is configured correctly.

Note: The PSoC™ 6 Bluetooth® LE Pioneer Kit (CY8CKIT-062-BLE) and the PSoC™ 6 Wi-Fi Bluetooth® Pioneer Kit (CY8CKIT-062-WIFI-BT) ship with KitProg2 installed. ModusToolbox™ requires KitProg3. Before using this code example, make sure that the board is upgraded to KitProg3. The tool and instructions are available in the Firmware Loader GitHub repository. If you do not upgrade, you will see an error like "unable to find CMSIS-DAP device" or "KitProg firmware is out of date".

Software setup

See the ModusToolbox™ tools package installation guide for information about installing and configuring the tools package. Install a terminal emulator if you don't have one. Instructions in this document use Tera Term.

This example requires no additional software or tools.

Using the code example

Create the project

The ModusToolbox™ tools package provides the Project Creator as both a GUI tool and a command line tool.

Use Project Creator GUI

1. Open the Project Creator GUI tool.

   There are several ways to do this, including launching it from the dashboard or from inside the Eclipse IDE. For more details, see the Project Creator user guide (locally available at {ModusToolbox™ install directory}/tools_{version}/project-creator/docs/project-creator.pdf).

2. On the Choose Board Support Package (BSP) page, select a kit supported by this code example. See Supported kits.

   Note: To use this code example for a kit not listed here, you may need to update the source files. If the kit does not have the required resources, the application may not work.

3. On the Select Application page:

   a. Select the Applications(s) Root Path and the Target IDE.

   Note: Depending on how you open the Project Creator tool, these fields may be pre-selected for you.

   b. Select this code example from the list by enabling its check box.

   Note: You can narrow the list of displayed examples by typing in the filter box.

   c. (Optional) Change the suggested New Application Name and New BSP Name.

   d. Click Create to complete the application creation process.

Use Project Creator CLI

The 'project-creator-cli' tool can be used to create applications from a CLI terminal or from within batch files or shell scripts. This tool is available in the {ModusToolbox™ install directory}/tools_{version}/project-creator/ directory.

Use a CLI terminal to invoke the 'project-creator-cli' tool. On Windows, use the command-line 'modus-shell' program provided in the ModusToolbox™ installation instead of a standard Windows command-line application. This shell provides access to all ModusToolbox™ tools. You can access it by typing "modus-shell" in the search box in the Windows menu. In Linux and macOS, you can use any terminal application.

The following example clones the "Dual-CPU IPC semaphore" application with the desired name "DualCPUIPCsemaphore" configured for the CY8CPROTO-062S2-43439 BSP into the specified working directory, C:/mtb_projects:

project-creator-cli --board-id CY8CPROTO-062S2-43439 --app-id mtb-example-psoc6-dual-cpu-ipc-sema --user-app-name DualCPUIPCsemaphore --target-dir "C:/mtb_projects"

The 'project-creator-cli' tool has the following arguments:

Argument	Description	Required/optional
--board-id	Defined in the field of the BSP manifest	Required
--app-id	Defined in the field of the CE manifest	Required
--target-dir	Specify the directory in which the application is to be created if you prefer not to use the default current working directory	Optional
--user-app-name	Specify the name of the application if you prefer to have a name other than the example's default name	Optional

Note: The project-creator-cli tool uses the git clone and make getlibs commands to fetch the repository and import the required libraries. For details, see the "Project creator tools" section of the ModusToolbox™ tools package user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mtb_user_guide.pdf).

Open the project

After the project has been created, you can open it in your preferred development environment.

Eclipse IDE

If you opened the Project Creator tool from the included Eclipse IDE, the project will open in Eclipse automatically.

For more details, see the Eclipse IDE for ModusToolbox™ user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mt_ide_user_guide.pdf).

Visual Studio (VS) Code

Launch VS Code manually, and then open the generated {project-name}.code-workspace file located in the project directory.

For more details, see the Visual Studio Code for ModusToolbox™ user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mt_vscode_user_guide.pdf).

Keil µVision

Double-click the generated {project-name}.cprj file to launch the Keil µVision IDE.

For more details, see the Keil µVision for ModusToolbox™ user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mt_uvision_user_guide.pdf).

IAR Embedded Workbench

Open IAR Embedded Workbench manually, and create a new project. Then select the generated {project-name}.ipcf file located in the project directory.

For more details, see the IAR Embedded Workbench for ModusToolbox™ user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mt_iar_user_guide.pdf).

Command line

If you prefer to use the CLI, open the appropriate terminal, and navigate to the project directory. On Windows, use the command-line 'modus-shell' program; on Linux and macOS, you can use any terminal application. From there, you can run various make commands.

For more details, see the ModusToolbox™ tools package user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mtb_user_guide.pdf).

Operation

1. Connect the board to your PC using the provided USB cable through the KitProg3 USB connector.

2. Open a terminal program and select the KitProg3 COM port. Set the serial port parameters to 8N1 and 115200 baud.

3. Program the board using one of the following:

   Using Eclipse IDE

   1. Select the application project in the Project Explorer.

   2. In the Quick Panel, scroll down, and click <Application Name> Program (KitProg3_MiniProg4).

   In other IDEs

   Follow the instructions in your preferred IDE.

   Using CLI

   From the terminal, execute the make program command to build and program the application using the default toolchain to the default target. The default toolchain is specified in the application's Makefile but you can override this value manually:

   make program TOOLCHAIN=<toolchain>
   

   Example:

   make program TOOLCHAIN=GCC_ARM
   

4. After programming, the application starts automatically. Confirm that "<CE Title>" is displayed on the UART terminal.

5. Press the user button on the kit. The terminal prints messages from both cores without any conflicts. Messages are printed every time you press the button.

   Figure 1. Terminal prints using semaphore

   

6. Set the #define ENABLE_SEMA to 0u in the shared/include/ipc_def.h file at line 41. Recompile the project and program it into the PSoC™ 6 MCU device. The red LED on the board should turn on, indicating that the semaphore is not used in the application.

7. Press the user button on the kit. The terminal will print messages from both CPUs, but with conflicts.

   Figure 2. Terminal prints without semaphore

   

   Note: Initially the customized configuration files like - design.cyqspi, design.cycapsense, design.modus are present in the folder templates/TARGET_< BSP-NAME >/config and are copied automatically from this folder to bsps/TARGET_< BSP-NAME >/config during the library updates. The build system reads all these configurations from the bsps/TARGET_< BSP-NAME >/config.

Debugging

You can debug the example to step through the code.

In Eclipse IDE

Use the <Application Name> Debug (KitProg3_MiniProg4) configuration in the Quick Panel. For details, see the "Program and debug" section in the Eclipse IDE for ModusToolbox™ user guide.

Add the below Note for relevant CEs only, like PSoC 6 MCU based. Remove this note for others.

Note: (Only while debugging) On the CM4 CPU, some code in main() may execute before the debugger halts at the beginning of main(). This means that some code executes twice – once before the debugger stops execution, and again after the debugger resets the program counter to the beginning of main(). See KBA231071 to learn about this and for the workaround.

In other IDEs

Follow the instructions in your preferred IDE.

Design and implementation

In this code example, the CM4 CPU is the primary CPU and is responsible for initializing the system. To avoid any access to uninitialized hardware, the CM0+ CPU waits for CM4 to complete the system initialization by using a semaphore. Before CM4 executes code, CM0+ locks a semaphore, releases CM4 to execute, and then goes to sleep until CM4 unlocks the semaphore.

The same semaphore is also used as a method to synchronize the access to a shared resource by the two CPUs. In this case, a UART block is the resource. Both CPUs print a message to the computer terminal through UART every time the user button is pressed. Before printing a message, both CPUs attempt to lock the semaphore. If it succeeds, it prints the message and then unlocks the semaphore afterwards. If the semaphore is already locked, it keeps trying to lock it until it succeeds.

The firmware has an option to disable the semaphore in the code. The semaphore is no longer locked by the CPUs by simply changing #define ENABLE_SEMA to 0u in the ipc_def.h file; additionally, the kit LED turns ON. Without the semaphore to synchronize access to the UART block, messages from both CPUs might overlap.

Figure 3. Firmware flowchart

Folder structure

This application has a different folder structure because it contains the firmware for CM4 and CM0+ applications as follows:

    |-- proj_cm0p/           # CM0+ application folder
        |-- main.c
        |-- Makefile
    |-- proj_cm4/            # CM4 application folder
        |-- main.c
        |-- Makefile
        |-- deps/           # All dependencies for CM4
    |-- shared/             # Shared folder for CM0+ and CM4
        |-- include/        # Shared header files

Resources and settings

Table 1. Application resources

Resource	Alias/object	Purpose
GPIO (PDL)	CYBSP_SW2	When pressed, prints messages to the console
GPIO (HAL)	CYBSP_USER_LED	User LED that turns ON when semaphore usage is disabled
UART (PDL)	CYBSP_UART	Prints messages to the console

Related resources

Resources	Links
Application notes	AN228571 – Getting started with PSoC™ 6 MCU on ModusToolbox™ AN215656 – PSoC™ 6 MCU: Dual-CPU system design
Code examples	Using ModusToolbox™ on GitHub
Device documentation	PSoC™ 6 MCU datasheets PSoC™ 6 technical reference manuals
Development kits	Select your kits from the Evaluation board finder.
Libraries on GitHub	mtb-pdl-cat1 – PSoC™ 6 Peripheral Driver Library (PDL) mtb-hal-cat1 – Hardware Abstraction Layer (HAL) library retarget-io – Utility library to retarget STDIO messages to a UART port
Middleware on GitHub	capsense – CAPSENSE™ library and documents psoc6-middleware – Links to all PSoC™ 6 MCU middleware
Tools	ModusToolbox™ – ModusToolbox™ software is a collection of easy-to-use libraries and tools enabling rapid development with Infineon MCUs for applications ranging from wireless and cloud-connected systems, edge AI/ML, embedded sense and control, to wired USB connectivity using PSoC™ Industrial/IoT MCUs, AIROC™ Wi-Fi and Bluetooth® connectivity devices, XMC™ Industrial MCUs, and EZ-USB™/EZ-PD™ wired connectivity controllers. ModusToolbox™ incorporates a comprehensive set of BSPs, HAL, libraries, configuration tools, and provides support for industry-standard IDEs to fast-track your embedded application development.

Other resources

Infineon provides a wealth of data at www.infineon.com to help you select the right device, and quickly and effectively integrate it into your design.

For PSoC™ 6 MCU devices, see How to design with PSoC™ 6 MCU - KBA223067 in the Infineon community.

Document history

Document title: CE230806 - PSoC™ 6 MCU: Dual-CPU IPC semaphore

Version	Description of change
1.0.0	New code example
2.0.0	Major update to support ModusToolbox™ software v2.2. This version is not backward compatible with ModusToolbox™ software v2.1
2.1.0	Added support for target CYSBSYSKIT-DEV-01
2.2.0	Added support for target CY8CKIT-062S4
2.3.0	Added support for new kits
3.0.0	Updated to BSP v3.X and added support for new kits
4.0.0	Major update to support ModusToolbox™ v3.0. This version is not backward compatible with previous versions of ModusToolbox™
4.1.0	Updated to support ModusToolbox™ v3.2. Added support for CY8CPROTO-062S2-43439, CY8CEVAL-062S2-LAI-43439M2, CY8CEVAL-062S2-MUR-4373M2, CY8CEVAL-062S2-MUR-4373EM2

All referenced product or service names and trademarks are the property of their respective owners.

The Bluetooth® word mark and logos are registered trademarks owned by Bluetooth SIG, Inc., and any use of such marks by Infineon is under license.

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