This example uses an OPTIGA™ Trust M V3 security solution along with a PSoC™ 6 MCU to execute example code to demonstrate the power management routines of the secure element. This example outputs the result and the time taken to perform the operations in a UART terminal.
In a nutshell, the hibernation feature on the OPTIGA™ Trust M means that a host MCU can power down the security solution by removing the power from it, but under certain conditions, the latter can hold all internal temporarily allocated information despite being disconnected from the power line.
The interconnection setup looks like the following:
Figure 1. Connection between PSoC™ 6 host MCU and OPTIGA™ Trust M
Provide feedback on this code example.
- ModusToolbox™ software v3.1 or later (tested with v3.1)
- Board support package (BSP) minimum required version: 4.0.0
- Programming language: C
- Associated parts:
- All PSoC™ 6 MCU parts
- OPTIGA™ Trust M V3
- GNU Arm® embedded compiler v11.3.1 (
GCC_ARM) - Default value ofTOOLCHAIN - Arm® compiler v6.16 (
ARM) - IAR C/C++ compiler v9.30.1 (
IAR)
- PSoC™ 62S2 evaluation kit (
CY8CEVAL-062S2,CY8CEVAL-062S2-LAI-43439M2,CY8CEVAL-062S2-LAI-4373M2,CY8CEVAL-062S2-MUR-43439M2,CY8CEVAL-062S2-MUR-4373EM2)
This example uses the board's default configuration. See the kit user guide to ensure that the board is configured correctly.
Create the project and open it using one of the following:
In Eclipse IDE for ModusToolbox™ software
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Click the New Application link in the Quick Panel (or, use File > New > ModusToolbox™ Application). This launches the Project Creator tool.
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Pick a kit supported by the code example from the list shown in the Project Creator - Choose Board Support Package (BSP) dialog.
When you select a supported kit, the example is reconfigured automatically to work with the kit. To work with a different supported kit later, use the Library Manager to choose the BSP for the supported kit. You can use the Library Manager to select or update the BSP and firmware libraries used in this application. To access the Library Manager, click the link from the Quick Panel.
You can also just start the application creation process again and select a different kit.
If you want to use the application 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.
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In the Project Creator - Select Application dialog, choose the example by enabling the checkbox.
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(Optional) Change the suggested New Application Name.
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The Application(s) Root Path defaults to the Eclipse workspace which is usually the desired location for the application. If you want to store the application in a different location, you can change the Application(s) Root Path value. Applications that share libraries should be in the same root path.
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Click Create to complete the application creation process.
For more details, see the Eclipse IDE for ModusToolbox™ software user guide (locally available at {ModusToolbox™ software install directory}/docs_{version}/mt_ide_user_guide.pdf).
In command-line interface (CLI)
ModusToolbox™ software provides the Project Creator as both a GUI tool and the command line tool, "project-creator-cli". The 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™ software 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™ software installation instead of a standard Windows command-line application. This shell provides access to all ModusToolbox™ software 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 "project-creator-cli" tool has the following arguments:
| Argument | Description | Required/optional |
|---|---|---|
--board-id |
Defined in the <id> field of the BSP manifest |
Required |
--app-id |
Defined in the <id> 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 |
The following example clones the "mtb-example-optiga-power-management" application with the desired name "OptigaCrypto" configured for the CYSBSYSKIT-DEV-01 BSP into the specified working directory, C:/mtb_projects:
project-creator-cli --board-id CY8CEVAL-062S2 --app-id mtb-example-optiga-power-management --user-app-name OptigaCrypto --target-dir "C:/mtb_projects"
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™ software user guide (locally available at {ModusToolbox™ software install directory}/docs_{version}/mtb_user_guide.pdf).
To work with a different supported kit later, use the Library Manager to choose the BSP for the supported kit. You can invoke the Library Manager GUI tool from the terminal using make library-manager command or use the Library Manager CLI tool "library-manager-cli" to change the BSP.
The "library-manager-cli" tool has the following arguments:
| Argument | Description | Required/optional |
|---|---|---|
--add-bsp-name |
Name of the BSP that should be added to the application | Required |
--set-active-bsp |
Name of the BSP that should be as active BSP for the application | Required |
--add-bsp-version |
Specify the version of the BSP that should be added to the application if you do not wish to use the latest from manifest | Optional |
--add-bsp-location |
Specify the location of the BSP (local/shared) if you prefer to add the BSP in a shared path | Optional |
In third-party IDEs
Use one of the following options:
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Use the standalone Project Creator tool:
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Launch Project Creator from the Windows Start menu or from {ModusToolbox™ software install directory}/tools_{version}/project-creator/project-creator.exe.
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In the initial Choose Board Support Package screen, select the BSP, and click Next.
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In the Select Application screen, select the appropriate IDE from the Target IDE drop-down menu.
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Click Create and follow the instructions printed in the bottom pane to import or open the exported project in the respective IDE.
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Use command-line interface (CLI):
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Follow the instructions from the In command-line interface (CLI) section to create the application.
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Export the application to a supported IDE using the
make <ide>command. -
Follow the instructions displayed in the terminal to create or import the application as an IDE project.
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For a list of supported IDEs and more details, see the "Exporting to IDEs" section of the ModusToolbox™ software user guide (locally available at {ModusToolbox™ software install directory}/docs_{version}/mtb_user_guide.pdf).
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Connect the board to your PC using the provided USB cable through the KitProg3 USB connector.
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Open a terminal program and select the KitProg3 COM port. Set the serial port parameters to 8N1 and 115200 baud.
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Program the board using one of the following:
Using Eclipse IDE for ModusToolbox™ software
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Select the application project in the Project Explorer.
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In the Quick Panel, scroll down, and click <Application Name> Program (KitProg3_MiniProg4).
Using CLI
From the terminal, execute the
make programcommand 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 -
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After programming, the application starts automatically. Confirm that the following text is displayed on the UART terminal.
Figure 2. Terminal output on program startup
You can debug the example to step through the code. In the IDE, use the <Application name> Debug (KitProg3_MiniProg4) configuration in the Quick Panel. For more details, see the "Program and debug" section in the Eclipse IDE for ModusToolbox™ software user guide.
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.
The code example demonstrates one of scenarios to prepare and make use of the hibernation feature of the OPTIGA™ Trust M security solution. In a nutshell, the host MCU can control the enablement of the hibernation feature on the OPTIGA™ device by sending a corresponding command to the chip over the I2C channel.
Important: To use all features provided by this example, your board should be able to control the power switch of the OPTIGA™ Trust M device. See Resources and settings.
Do the following:
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Open the application on the security solution as usual.
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Generate an ECC key pair and store the result in a session object.
The session object is located in a volatile memory and thus is erased each time the chip is powered off.
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To enter hibernate mode, the security monitor counter should be 0. Note that the previous step performed a crypto operation that caused the security monitor counter to increment to 1.
Note: To learn more about the security monitor and its operation, see this Wiki page.
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Enter hibernate mode and save the communication context on both sides (host MCU and security solution) by closing the application with the hibernate flag set to '1'.
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Open the application once again with the hibernate flag set to '1'. This restores the old communication context and all temporally stored data on the security solution.
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Generate an ECDSA signature using the private key from the session object. In normal conditions with no hibernate option used, that would be not possible, because the session object would be empty.
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Verify the signature using the public key saved in Step 2.
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Close the application without transitioning to hibernate mode.
Hibernate mode plays a very important role if a shielded communication is used (protected I2C connection). Both the host MCU and the security solution maintain a session context that contains several aspects of the communication. This information is temporally stored on the security solution (the host side can theoretically store it) and is by default erased after every power cycle.
If the hibernate feature is not used, that session context must be established every single time. This leads to a platform-binding secret usage, thus triggering a SEC counter (security monitor counter). If this is triggered too often, eventually every system power-up routine will take a lot of time. The latter would be required because to use the OPTIGA™ Trust M device, the host MCU must wait until the SEC counter reaches a value when a new security relevant operation can be performed.
OPTIGA™ Trust M automatically enters a low-power mode after a configurable delay. This isn't hibernation mode, which can be entered only on demand by sending a corresponding command from the host MCU to the security solution. Once it has entered sleep mode, the OPTIGA™ solution resumes the normal operation as soon as its address is detected on the I2C bus. If no command is sent to the chip, it behaves as show in Figure 3.
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As soon as the OPTIGA™ device is idle, it starts to count down a "delay to sleep" time (tsdy).
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When this time elapses, the device enters a "go to sleep" procedure.
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The "go to sleep" procedure waits until all idle tasks are completed (e.g., counting down the SEC counter). If all idle tasks are completed and no command is pending, the OPTIGA™ device enters sleep mode.
Figure 3. Go-to-sleep diagram
| OPTIGA™ Trust M pins | Assigned GPIOs by default | Notes |
|---|---|---|
| I2C SDA (I/O) | CYBSP_TRUSTM_I2C_SDA | Any GPIO connected to the I2C SDA line can be used. |
| I2C SCL (Clock) | CYBSP_TRUSTM_I2C_SCL | Any GPIO connected to the I2C SDA line can be used. |
| RST (Reset) | CYBSP_TRUSTM_RST | An optional control pin if defined in optiga_lib_config_mtb.h |
| VDD (Power control) | (Optional) CYBSP_TRUSTM_VDD | An optional control pin if defined in optiga_lib_config_mtb.h |
| optiga_lib_config_mtb.h macros | Meaning | Default value |
|---|---|---|
OPTIGA_CRYPT_XXXX |
Controls whether to enable/disable selected crypto support on the host library side | All enabled |
OPTIGA_COMMS_SHIELDED_CONNECTION and OPTIGA_COMMS_DEFAULT_PROTECTION_LEVEL |
Together define whether to use and the extent of use of the shielded connection (encrypted and integrity-protected I2C communication) | Defined OPTIGA_COMMS_SHIELDED_CONNECTION |
OPTIGA_COMMS_DEFAULT_RESET_TYPE |
The reset type if VDD or RST pin is defined. Choose 1 or 2 depending on the combination used. VDD can be used in certain cases as a reset line, but it is recommended to use them separately. | 2 |
OPTIGA_CMD_MAX_REGISTRATIONS |
Controls the number of crypt/util registrations allowed. In a very basic scenario, this can be reduced to 2 (one registration each for crypt and util). |
6 |
OPTIGA_MAX_COMMS_BUFFER_SIZE |
Maximum buffer size that the command layer should be able to store intermediately | 0x615 |
OPTIGA_LIB_ENABLE_LOGGING |
Controls whether logging can be enabled in general | Defined |
OPTIGA_LIB_ENABLE_UTIL_LOGGING |
If defined together with OPTIGA_LIB_ENABLE_LOGGING, outputs messages relevant to the util API |
Undefined |
OPTIGA_LIB_ENABLE_CRYPT_LOGGING |
If defined together with OPTIGA_LIB_ENABLE_LOGGING, outputs messages relevant to the crypt API |
Undefined |
OPTIGA_LIB_ENABLE_CMD_LOGGING |
If defined together with OPTIGA_LIB_ENABLE_LOGGING, outputs the application protocol data unit (APDU) sent to the OPTIGA™ Trust M external interface (See the solution reference manual) |
Undefined |
OPTIGA_LIB_ENABLE_COMMS_LOGGING |
If defined together with OPTIGA_LIB_ENABLE_LOGGING, prints out I2C frames |
Undefined |
| Resources | Links |
|---|---|
| Application notes | AN228571 – Getting started with PSoC™ 6 MCU on ModusToolbox™ software AN215656 – PSoC™ 6 MCU: Dual-CPU system design |
| Code examples on GitHub | Using ModusToolbox™ software |
| Device documentation | PSoC™ 6 MCU datasheets PSoC™ 6 technical reference manuals OPTIGA™ Trust M datasheet |
| Development kits | Select your kits from the Evaluation Board Finder page. |
| 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 | optiga-trust-m – OPTIGA™ Trust M library and documents capsense – CAPSENSE™ library and documents psoc6-middleware – Links to all PSoC™ 6 MCU middleware |
| Tools | Eclipse IDE for ModusToolbox™ software – ModusToolbox™ software is a collection of easy-to-use software and tools enabling rapid development with Infineon MCUs, covering applications from embedded sense and control to wireless and cloud-connected systems using AIROC™ Wi-Fi and Bluetooth® connectivity devices. |
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 Developer Community.
Document title: CE233734 – OPTIGA™ Trust M: Power management
| Version | Description of change |
|---|---|
| 1.0.0 | New code example |
| 2.0.0 | Support the MTB 3.X and use the latest optiga-trust-m lib |
| 2.1.0 | Added support for new kits |
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