EZ-PD™ PMG1 MCU: Watchdog timer

This code example demonstrates the method of using the watchdog timer (WDT) on EZ-PD™ PMG1 devices to automatically reset the device in the event of an unexpected firmware execution path that compromises the CPU functionality. It also explains the configuration of the watchdog timer as an interrupt source to generate a periodic interrupt that can be used to execute specific tasks.

View this README on GitHub.

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Requirements

• ModusToolbox™ v3.0 or later (tested with v3.0)
• Board support package (BSP) minimum required version: 3.0.0
• Programming language: C
• Associated parts: All EZ-PD™ PMG1 MCU parts

Supported toolchains (make variable 'TOOLCHAIN')

• GNU Arm® Embedded Compiler v10.3.1 (GCC_ARM) – Default value of TOOLCHAIN
• Arm® Compiler v6.13 (ARM)
• IAR C/C++ Compiler v8.42.2 (IAR)

Supported kits (make variable 'TARGET')

• EZ-PD™ PMG1-S0 Prototyping Kit (PMG1-CY7110) – Default value of TARGET
• EZ-PD™ PMG1-S1 Prototyping Kit (PMG1-CY7111)
• EZ-PD™ PMG1-S2 Prototyping Kit (PMG1-CY7112)
• EZ-PD™ PMG1-S3 Prototyping Kit (PMG1-CY7113)
• EZ-PD™ PMG1-B1 Prototyping Kit (EVAL_PMG1_B1_DRP)

Hardware setup

1. Connect the board to your PC using a USB cable through the KitProg3 USB Type-C port (J1). This cable is used for programming the PMG1 device and can be used during debugging.

2. Connect the PMG1 USB PD sink port (J10) to a USB-C power adapter/USB port on the PC using a Type-C/Type-A to Type-C cable to power the PMG1 kit for normal operation.

3. If UART DEBUG PRINT messages are enabled, a UART connection is needed. See Compile-time configurations for more information on the UART DEBUG PRINT. Pin connections for UART is shown in the table below. For the following revisions of the PMG1 prototyping kits, in order to establish a UART connection between KitProg3 and the PMG1 device connect the UART Tx and UART Rx lines as follows:

   Table 1. PMG1 kit UART connection

   PMG1 kit	UART Tx	UART Rx
   PMG1-CY7110 (revision 3 or lower)	J6.10 to J3.8	J6.9 to J3.10
   PMG1-CY7111 (revision 2 or lower)	J6.10 to J3.8	J6.9 to J3.10
   PMG1-CY7112 (revision 2 or lower)	J6.10 to J3.8	J6.9 to J3.10
   PMG1-CY7113 (revision 3 or lower)	J6.10 to J3.8	J6.9 to J3.10
   EVAL_PMG1_B1_DRP	SW5 to 1-2 position	SW4 to 1-2 position

Note: All prototyping kits with a higher revision have UART lines internally connected. Therefore, external wiring is not required.

Software setup

See the ModusToolbox™ tools package installation guide for information about installing and configuring the tools package.

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 "mtb-example-pmg1-watchdog-timer" application with the desired name "MyWatchdogtimer" configured for the PMG1-CY7110 BSP into the specified working directory, C:/mtb_projects:

project-creator-cli --board-id PMG1-CY7110 --app-id mtb-example-pmg1-watchdog-timer --user-app-name MyWatchdogtimer --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. Ensure that the steps listed in the Hardware setup section are completed.

2. Ensure that the jumper shunt on the power selection jumper (J5) is placed at position 2-3 to enable programming mode for PMG1-CY7110, PMG1-CY7111, PMG1-CY7112, and PMG1-CY7113 prototyping kits. Skip this step for EVAL_PMG1_B1_DRP kit.

3. Connect the PMG1 kit to your PC using the USB cable through the KitProg3 USB Type-C port (J1). This cable is used for programming the PMG1 device.

4. Program the kit using one of the following:

   Using Eclipse IDE for ModusToolbox™

   1. Select the application project in the Project Explorer.

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

   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 and target are specified in the application's Makefile but you can override those values manually:

   make program TOOLCHAIN=<toolchain>
   

   For Example:

   make program TOOLCHAIN=GCC_ARM
   

5. After programming the kit, disconnect the USB cable. Move to the next step for EVAL_PMG1_B1_DRP kit. Change the position on the power selection jumper (J5) to 1-2, to power the kit through the USB PD port (J10) for PMG1-CY7110, PMG1-CY7111, PMG1-CY7112, and PMG1-CY7113 prototyping kits.

6. Now connect the USB cable to the PMG1 USB PD sink port (J10) to power the PMG1-CY7110, PMG1-CY7111, PMG1-CY7112, and PMG1-CY7113 prototyping kits. The EVAL_PMG1_B1_DRP kit is automatically powered when the kit is connected through the KitProg3 USB Type-C port (J1).

7. The application starts automatically. Note that, by default, the watchdog timer (WDT) is configured in WDT reset mode. In this configuration, the user LED blinks once for any reset other than WDT reset and blinks thrice for every WDT reset.

8. Press the reset switch (SW3) of the PMG1-CY7111, PMG1-CY7112, PMG1-CY7113 and EVAL_PMG1_B1_DRP kit to issue an XRES trigger (SW3 is not available on PMG1-S0). Similarly, remove and reconnect the power to the kit to execute a power-on reset (POR). In both these cases, the user LED (LED3) blinks once.

9. Press the user switch (SW2) to simulate an unexpected firmware execution event. Note that in this case, the user LED blinks thrice indicating a WDT reset.

10. See the Design and implementation section to configure the watchdog timer in interrupt mode. In this configuration, a periodic interrupt is generated by the watchdog timer and is indicated by the toggling user LED.

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. Ensure that the board is connected to your PC using the USB cable through the KitProg3 USB Type-C port (J1) and for PMG1-CY7110, PMG1-CY7111, PMG1-CY7112, and PMG1-CY7113 prototyping kits the jumper shunt on power selection jumper (J5) is placed at position 1-2.

See the Debug mode section in the kit user guide for debugging the application on the CY7110 prototyping kit. See the Debugging using ModusToolbox™ section in AN238945 for EVAL_PMG1_B1_DRP kit. For more details, see the Program and debug section in the Eclipse IDE for ModusToolbox™ user guide.

In other IDEs

Follow the instructions in your preferred IDE.

Design and implementation

This code example uses the watchdog timer (WDT) resource available on PMG1 devices in two modes: WDT reset mode and WDT interrupt mode. The WDT is a 16-bit free-running, wrap-around, up-counter sourced by the low-frequency clock (LFCLK) (32-kHz clock). Here, the WDT can be configured by assigning a suitable value to the following macros in the main.c file:

• WDT_TICKS_COUNT denotes the match value set for the watchdog timer. It also specifies the number of counts generated by the WDT before a match event. Whenever a match event occurs, an interrupt is triggered. The maximum possible value is 65535 indicating the 16-bit timer overflow. A lower match value will reduce the WDT interrupt period and vice versa. This value is used for fine adjustments of the WDT interrupt period.

• WDT_IGNORE_BITS denotes the number of most significant bits (MSb) that will be ignored when calculating the match value. Its value can range from 0–15. For example, if the number of ignore bits is set to '2', then the WDT becomes a 14-bit counter. This value is used for course adjustments of WDT interrupt period. However, this application requires its value to be lower than '3' (in WDT reset mode) to prevent continuous reset generation due to constraints from the looping delay.

WDT mode configuration

• WDT reset mode (default): In this code example, the WDT in reset mode by default is assigned the value (0u) to the WDT_INTERRUPT_MODE macro in main.c file. This masks all the pending WDT interrupts from the CPU and enables generating the WDT system reset. WDT interrupts are regularly cleared from the main function to prevent system reset. However, when the user switch (SW2) is pressed, the CPU enters an infinite loop simulating an unexpected firmware execution path. This results in two consecutive uncleared WDT interrupts and triggers a system reset on the third match event. Whenever a reset occurs, the reset cause is read and the user LED is blinked accordingly to indicate the type of the reset.

• WDT interrupt mode: To configure the WDT in interrupt mode, assign the value (1u) to the WDT_INTERRUPT_MODE macro in main.c. This initializes the WDT interrupt, hooks up an interrupt service routine (ISR), and enables the WDT interrupt. The system reset generation due to WDT is disabled and the WDT interrupt is unmasked. In the corresponding ISR, interrupts are cleared and a new incremental match value is assigned to generate interrupts at regular time intervals. The user LED toggles each time to indicate a WDT interrupt.

  Note: Alternatively, the watchdog timer can be configured using the Device Configurator to specify the match value and ignore bits. This is done by enabling the watchdog timer (WDT) under Peripherals tab in the Device Configurator. However, this example uses the API functions Cy_WDT_SetMatch() and Cy_WDT_SetIgnoreBits() in main.c file to assign the respective values to the watchdog timer.

Figure 1. Firmware flowchart

Resources and settings

Table 1. Application resources

Resource	Alias/object	Purpose
Watchdog timer (WDT) (PDL)	-----	Used for interrupt generation and system reset
LED(BSP)	CYBSP_USER_LED	User LED to indicate interrupt and type of reset

Compile-time configurations

The EZ-PD™ PMG1 MCU watchdog timer application functionality can be customized through a set of compile-time parameters that can be turned ON/OFF through the main.c file.

Macro name	Description	Allowed values
DEBUG_PRINT	Debug print macro to enable UART print	1u to enable 0u to disable

Related resources

Resources	Links
Application notes	AN232553 – Getting started with EZ-PD™ PMG1 MCU on ModusToolbox™ AN232565 – EZ-PD™ PMG1 hardware design guidelines and checklist AN238945 – Getting started with EZ-PD™ PMG1-B1 MCU using ModusToolbox™
Code examples	Using ModusToolbox™ on GitHub
Device documentation	EZ-PD™ PMG1 MCU datasheets EZ-PD™ PMG1 MCU technical reference manuals
Development kits	Select your kits from the Evaluation board finder.
Libraries on GitHub	mtb-pdl-cat2 – Peripheral Driver Library (PDL)
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.

Document history

Document title: CE235174 – EZ-PD™ PMG1 MCU: Watchdog timer

Version	Description of change
1.0.0	New code example
2.0.0	Major update to support ModusToolbox™ v3.0. This version is not backward compatible with previous versions of ModusToolbox™
2.1.0	Updated to support EVAL_PMG1_B1_DRP Kit

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