CYW5591x Low power

This is low power application for CYW5591x devices. The application provides a simple UART interface to manipulate the device state and hence facilitating the system power measurement in different scenarios. This code example should be used along with AN239828: AIROC(TM) CYW55913 Wi-Fi & Bluetooth® connected MCU low-power system design for better understanding.

View this README on GitHub.

Provide feedback on this code example.

Requirements

• ModusToolbox™ software v3.2 or later (tested with v3.2)
• Board support package (BSP) minimum required version for : v1.0.0.
• Programming language: C
• Associated parts: CYW955913EVK-01

Supported toolchains (make variable 'TOOLCHAIN')

• GNU Arm® Embedded Compiler v11.3.1 (GCC_ARM) – Default value of TOOLCHAIN

Supported kits (make variable 'TARGET')

• CYW955913EVK-01 Wi-Fi Bluetooth® prototyping kit (CYW955913EVK-01) – Default value of TARGET

Hardware setup

This example requires rework to enable power mesurement on the Kit. Please refer to section 7.1: Hardware setup in AN239828: AIROC(TM) CYW55913 Wi-Fi & Bluetooth® connected MCU low-power system design for complete rework details and setup.

Software setup

Install a terminal emulator if you don't have one. Instructions in this document use Tera Term.

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 "CYW5591x Low Power" application with the desired name "MyLowPowerApp" configured for the CYW955913EVK-01 BSP into the specified working directory, C:/mtb_projects:

project-creator-cli --board-id CYW955913EVK-01 --app-id mtb-example-threadx-cyw5591x-low-power --user-app-name MyLowPowerApp --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. Program using one of the following and reset the board:

   Using Eclipse IDE for ModusToolbox™ software

   1. Select the application project in the Project Explorer.

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

   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 TARGET=APP_<BSP> TOOLCHAIN=<toolchain>
   

   Example:

   make program TARGET=APP_CYW955913EVK-01 TOOLCHAIN=GCC_ARM
   

3. Following instructions appear on the terminal on application start:

   • Press '1' to initialize WLAN

     • This option allows you to initialize the WLAN CR4 core, the wifi host driver (WHD) and wifi connection manager.

   • Press '2' to connect to an AP, Enter AP SSID and password when prompted.

     • This option allows you to connect to an access point. Once selected it will prompt you for the AP's SSID and password.

     Note: Make sure the terminal being used has New Line Transmit set to CR and not CR+LF as it is used identify the end of user input.
     

   • Press '3' to start iperf session

     • This option start's an iperf server. This should only be used to simulate data traffic as it is not optimized to provide best throughput. Start a client on a different machine and connect to the server. Note: This iperf utility is based on iperf2, Please use the same on the client

   • Press '4' to initialize Bluetooth®.

     • This will initialize the Bluetooth® stack. Note: Bluetooth Initialization should be done before Wi-Fi initialization. If you plan to use both, please follow the recommended order Bluetooth® Init -> Wi-FI Init.

   • Press '5' to start Bluetooth® LE advertisements

     • This will start Bluetooth® advertisements with Device name "Low Power".

   • Press '6' to lock sleep

     • This will acquire a sleep lock and will prevent the device from sleeping.

   • Press '7' to allow sleep

     • This will release the sleep lock and will allow the device to sleep. The application by default starts with a sleep lock to allow manipulation of system state before measuring power.

   • Press '8' to disconnect from the AP.

     • This option is used to disconnect an existing connection to an AP.

   • Press '9' any time in application to start scan.

     • This option is used to scan for available AP's in the range.

   • Press 'h' any time in application to print the menu

     • This option is used to request the Start menu options to view the options availabe at any point in the program.

   Use these available commands to interact with the application and achieve the required state for which you want to measure the power. Once done proceed with power measurements.

Design and implementation

The application provides a simple UART interface for facilitating low power measurements for CYW55913.It starts by taking a sleep lock which is required to interact with the application and issue commands. If the device goes to sleep, the UART communication will be suspended hence the need for sleep lock. Once the desired state is achieved, we can release the lock for the power measurement by issuing command 7. furthermore we can wake the device up using USER BTN (SW4) to make further changes in the state if needed. During GPIO wake, we take a sleep lock to facilitate the same by keeping UART communication active until we have our desired state.

Lets look at the application structure in Table 1 and some of the important functions in table 2.

Table 1. Source folders Description

Folder	Description
LPSrc	Contains source files related to System low power interface.
WLANSrc	Contains source files with functions related to WLAN handling.
BluetoothSrc	Contains source files with functions related to Bluetooth® LE handling.

Table 2. Overview of Important functions

Functions	Description
main	Initializes the BSP Enables Global interrupts Creates UART task for handling user commands Resgisters System Power manager callback for low power
uart_task	Processes the received commands via terminal and implements necessary handling
lp_wlan_init	Initializes wifi connection manager.
connect_to_wifi_ap	Connects to Wi-Fi AP using the user-provided credentials
iperf_util_thread_app	Starts Iperf server for simulating WLAN traffic
network_idle_task	Monitors and suspends network stack when there is no network activity.
tcp_socket_connection_start	Connects to the configured offload TCP server in device configfurator.
pm_callback	Receives the low power transition callbacks from SysPM Module
le_app_management_callback	Receivea management events from the Bluetooth® LE stack and process as per the application.
le_app_gatt_event_callback	This function handles GATT events from the Bluetooth® LE stack

The menu explained in the operation section provides easy way to measure low power in different scenarios. Let's take a look at one such scenario, suppose we want to measure current when we are associated to an AP with no network activity. In this case we need to first initialise the Wifi interface (Command 1) , connect to an AP (command 2 ) and then release the sleep lock to allow device to go to sleep ( command 7). The Low power assistant in the network_idle_task takes care of suspending the network stack in case of inactivity. Make sure to set the appropriate DTIM (Delivery traffic indication message) value in the Access point for which you want the power measurement. For power numbers for various scnearios please refer AN239828: AIROC(TM) CYW55913 Wi-Fi & Bluetooth® connected MCU low-power system design.

Note: For cases where both Bluetooth and the Wi-Fi needs to be used make sure to initialise the Bluetooth first.

Offloads:

CYW55913 supports ARP, Packet filter and TCP keep alive offloads. The application by default enables ARP and packet filter offload (Ping discard filter) via a custom design.modus file present inside templates folder. To understand more about these offloads refer the companion Application Note and Low power assistant Documentation. In the case where ARP offload is enabled CM33 (Host) will not wake up for responding to ARP requests and the same can be observed on the power analyser. Sniffer can be used to monitor that ARP requests are getting honoured. Refer to Low Power Assistant documentation for detailed information about offloads including how to configure and test them.

Note: LPA on network suspension prints out this message : "Network Stack Suspended, MCU will enter Active power mode" . Please ignore the MCU state mentioned here.

Note: TCP Keep alive although supported is not yet enabled in the CE, will be added in subsequent release.

System Power Manager (SysPM):

SysPM Hardware abstraction Module allows the users to manage the entry and exit into low power modes. The application modules can register callback to SysPM to get information of different transition states and do any processing if required. The pm_callback function mentioned in Table 2 is one such example of the same. The SysPM module also provides sleep lock and unlock API's which when called will prevent the device from going to sleep.

Related resources

Resources	Links
Device documentation	Contact infineon sales for device documentation
Development kits	Contact infineon sales for kit samples
Application Notes	AN239828: AIROC(TM) CYW55913 Wi-Fi & Bluetooth® connected MCU low-power system design
Libraries on GitHub	Low Power Assistant - Low power helper library mtb-pdl-cat5 – CYW55913 peripheral driver library (PDL) mtb-hal-cat5 – Hardware abstraction layer (HAL) library retarget-io – Utility library to retarget STDIO messages to a UART port
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.

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: CE240060 – CYW5591x Low Power

Version	Description of change
1.0.0	New code example
1.1.0	bug fix

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