infineon / mtb-example-btsdk-cyw20719b2-spi

This application demonstrates how to use the SPI driver interface to send and receive bytes or a stream of bytes over the SPI hardware.

SPI

This code example includes two applications that demonstrate the operation of serial peripheral interface (SPI) using the CYW20719B2 Bluetooth® SoC and ModusToolbox™ software.

This code example has two applications:

1. SPI master: This application is used for collecting the sensor data.
2. SPI slave: This application provides sensor data to the first application, i.e. SPI Master.

View this README on GitHub.

Provide feedback on this code example.

Requirements

• ModusToolbox™ software v2.2 or later (tested with v2.3).

  Note: This code example version requires ModusToolbox™ software version 2.2 or later and is not backward compatible with v2.1 or older versions. If you cannot move to ModusToolbox™ software v2.2, use the latest compatible version of this example: latest-v1.X.

• Board support package (BSP) minimum required version: 3.0.0

• Programming language: C

• Associated parts: AIROC™ CYW20719 Bluetooth® & Bluetooth® LE system-on-chip

Supported toolchains (make variable 'TOOLCHAIN')

• GNU Arm® embedded compiler v9.3.1 (GCC_ARM) - Default value of TOOLCHAIN

Supported kits (make variable 'TARGET')

• CYW920719B2Q40EVB-01 evaluation kit

Hardware setup

These applications run on two separate kits. Both of them use the kit's default configuration. Figure 1 shows the block diagram depicting the connections between different blocks of two evaluation boards.

Figure 1. Block diagram

Table 1. Hardware connections

Function	Master GPIO	EVB header pin	Arduino header	Slave GPIO	EVB header pin	Arduino header
CLK	WICED_P38	J3.5	D13	WICED_P38	J3.5	D13
MISO	WICED_P01	J3.6	D12	WICED_P01	J3.6	D12
MOSI	WICED_P04	J4.1	D07	WICED_P04	J4.1	D07
CS	WICED_P02	J3.8	D06	WICED_P02	J3.8	D06
GND	GND	J3.4	GND	GND	J3.4	GND

Software setup

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 and open it using one of the following:

In Eclipse IDE for ModusToolbox™ software

1. Click the New Application link in the Quick Panel (or, use File > New > ModusToolbox Application). This launches the Project Creator tool.

2. 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 and deselect the other BSPs. Keep only the required BSP in your application. 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.

3. In the Project Creator - Select Application dialog, choose the SPI application by enabling the checkbox.

4. (Optional) Change the suggested New Application Name.

5. 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.

6. 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}/ide_{version}/docs/mt_ide_user_guide.pdf).

Note: Both the SPI master and SPI slave applications are created for the same kit that you have selected in Step 2.

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.

This 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 will clone the "Hello World" application with the desired name "MyHelloWorld" configured for the CY8CKIT-062-WIFI-BT BSP into the specified working directory, C:/mtb_projects:

project-creator-cli --board-id CY8CKIT-062-WIFI-BT --app-id mtb-example-psoc6-hello-world --user-app-name MyHelloWorld --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).

In third-party IDEs

Use one of the following options:

• Use the standalone Project Creator tool:

  1. Launch Project Creator from the Windows Start menu or from {ModusToolbox™ software install directory}/tools_{version}/project-creator/project-creator.exe.

  2. In the initial Choose Board Support Package screen, select the BSP, and click Next.

  3. In the Select Application screen, select the appropriate IDE from the Target IDE drop-down menu.

  4. Click Create and follow the instructions printed in the bottom pane to import or open the exported project in the respective IDE.

• Use command-line interface (CLI):

  1. Follow the instructions from the In command-line interface (CLI) section to create the application, and then import the libraries using the make getlibs command.

  2. Export the application to a supported IDE using the make <ide> command.

  3. Follow the instructions displayed in the terminal to create or import the application as an IDE project.

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).

Operation

Using two Bluetooth® system-on-chip (SoC) boards:

1. Connect one of the two boards to your PC using the provided USB cable through the USB connector.

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

3. Program the board with the SPI_master application.

   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=<BSP> TOOLCHAIN=<toolchain>
   

   Example:

   make program TARGET=CYW920719B2Q40EVB-01 TOOLCHAIN=GCC_ARM
   

4. After programming is successful, unplug first board and connect the second board to your PC. Follow the same procedure as mentioned above for SPI_Slave application.

   Note: If the download fails, it is possible that a previously loaded application is preventing programming. For example, application might use a custom baud rate that the download process does not detect or it might be in a low power mode. In this case, it may be necessary to put the board in recovery mode, and then try the programming operation again from the IDE. To enter recovery mode, first, press and hold the Recover button (SW1), then press the Reset button (SW2), release the Reset button (SW2), and then release the Recover button (SW1).

5. After programming, press Reset button of master board and applications start automatically.

6. The master and slave serial terminal window display the received SPI command and the accompanying response on the terminal window, as shown in Figure 2 and Figure 3.

   Figure 2. Serial terminal output of SPI master

   

   Figure 3. Serial terminal output of SPI slave

   

Design and implementation

SPI master

This section describes the details of the implementation of the SPI master.

On startup, the application sets up the UART and then starts the Bluetooth® stack in application_start(). Once the stack is started (BTM_ENABLED_EVT), it calls the initialize_app() function, which handles the remaining functionality. Note that the Bluetooth® stack is running; since Bluetooth® is not used in this application, it does not do anything once the stack is started. The initialize_app() function initializes the SPI interface, RTC, GPIO and a thread to read SPI sensor.

Following is the description of the variables used:

• dec_temp: Holds the decimal part of the temperature reading
• frac_temp: Holds the fractional part of the temperature reading

In the thread handling SPI communication with the slave (spi_sensor_thread), a finite state machine is used to determine the data that the master requests, as shown in Figure 4.

Figure 4. Finite state machine adopted for communicating with slave

The finite state machine contains three states:

• SENSOR_DETECT
• READ_UNIT
• READ_TEMPERATURE

In each state, the slave is verified to be a known slave using a packet header before processing the data that is sent from the slave. If the master is not able to authenticate the slave, the master remains in the same state and retries. After five retries, the SPI interface is reset, and the master starts from the SENSOR_DETECT state.

In the SENSOR_DETECT state, the master requests the Manufacturer ID to verify whether the slave’s manufacturer is Infineon®. If the slave responds with an unknown Manufacturer ID, the master informs the user that the slave’s identity could not be authenticated. If the slave responds with the expected Manufacturer ID, the master enters the next state, READ_UNIT. A flowchart illustrating the operation is shown in Figure 5.

Figure 5. Flowchart of SENSOR_DETECT state

Unit ID to know the unit of temperature values provided by the slave. If the slave responds with an unknown Unit ID, the master informs the user that the unit of temperature is unknown and tries to obtain the unit again. If the number of retries exceeds 5, the master changes its state to SENSOR_DETECT. Otherwise, if the slave responds as expected, the master enters the next state, READ_TEMPERATURE. A flowchart illustrating the operation is shown in Figure 6.

Figure 6. Flowchart of READ_UNIT state

In the READ_TEMPERATURE state, the master requests the temperature from the slave. The temperature reading received comprises the decimal and fractional parts of the temperature. For instance, if the temperature reading is 24.44 °C, the slave sends 2444 as the data. The master then stores the quotient as the decimal part of temperature and remainder as the fractional part of temperature in the temperature record. A flowchart illustrating the operation is shown in Figure 7.

Figure 7. Flowchart of READ_TEMPERATURE state

The application level source files for spi_master is listed in Table 2.

Table 2. Application source files

File name	Description
spi_master.c	Contains the application_start() function which is the entry point for execution of the user application code after device startup and the thread that handle SPI communication with sensor.

SPI slave

This section describes the operation of the slave. As with the master, application_start() sets up the UART and then starts the Bluetooth® stack. Once the stack is started (BTM_ENABLED_EVT), it initializes the ADC and then calls the initialize_app() function which handles the remaining functionality. Note that the Bluetooth® stack is running; since Bluetooth® is not used in this application, it does not do anything once the stack is started. The initialize_app() function sets up the SPI interface, initializes the thermistor and then waits for and responds to SPI master commands. There are three commands that the slave will respond to:

• Manufacturer ID: The slave responds with its Manufacturer ID.
• Unit ID: The slave responds with its Unit ID
• Temperature: The slave responds with a temperature reading obtained by acquiring ADC samples

The slave reads from SPI Rx buffers only when its Tx buffers are empty. If the slave is unable to empty the Tx buffers after several retries, the SPI interface is reset. A flowchart illustrating the operation of the slave is shown in Figure 8.

Figure 8. SPI slave operation

The application level source files for “spi_slave” are listed in Table 3.

Table 3. Application source files

File name	Description
spi_slave.c	Contains the application_start() function which is the entry point for execution of the user application code after device startup.

Resources and settings

This section explains the ModusToolbox™ software resources and their configuration as used in this code example. Note that all the configuration explained in this section has already been done in the code example. Eclipse IDE for ModusToolbox™ software stores the configuration settings of the application in the design.modus file. This file is used by the graphical configurators, which generate the configuration firmware. This firmware is stored in the application’s GeneratedSource folder.

• Device configurator: Used to enable/configure the peripherals and the pins used in the application. See the Device configurator guide.

• Bluetooth® configurator: Used for generating/modifying the Bluetooth® LE GATT database. See the Bluetooth® configurator guide.

Related resources

Resources	Links
Application notes	AN225684: Getting started with CYW208xxDescribes CYW208xx device and how to build your first ModusToolbox™ software project
Code examples	Using ModusToolbox™ software on GitHub Using Bluetooth™ Creator
Device documentation	CYW20719 device datasheet
Development kits	Visit https://www.cypress.com/products/airoc-bluetooth-le-bluetooth
Libraries on GitHub	btsdk-drivers – Bluetooth® SDK drivers library btsdk-mesh – Bluetooth® LE mesh libraries btsdk-ota – Bluetooth® LE OTA libraries btsdk-ble – Bluetooth® LE profile libraries
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. btsdk-utils – Bluetooth® SDK utilities btsdk-peer-apps-ota – Bluetooth® LE OTA peer applications btsdk-host-peer-apps – Bluetooth® LE Mesh Host and peer applications btsdk-host-apps-bt-ble – Bluetooth® and Bluetooth® LE Host applications

Other resources

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

Document history

Document title: CE229103 – SPI

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	Updated to support ModusToolbox™ software v2.3.1
2.1.1	Updated the Documentation

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