Getting Started with FRDM-KW41Z

Find out more.

• True debug support via SWD and JTAG
• High software flexibility
• Full set of peripheral drivers with source
• Application examples and project files

Find out more .

• A scalable, open source real-time operating system (RTOS)
• Supports multiple hardware architectures
• Optimized for resource constrained devices
• Built with security in mind

Note: Selecting Zephyr OS will direct you to the Zephyr OS developer website.

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• Online compiler, no SWD or JTAG debug
• Simple, heavily abstracted programming interface
• Useful but limited drivers with source
• Community-submitted examples

Note: Selecting Mbed will direct you to the Mbed developer website.

These steps show how to:

1. Load and build the demo application in IAR Embedded Workbench
2. Download and run the demo application

The example used below is for the SMAC Connectivity Test demo, but these steps can be applied to any of the Wireless Connectivity demo applications.

Load and build the application demo

1. Navigate to the Connectivity Test IAR workspace (located at <install_dir>\boards\frdmkw41z\wireless_examples\smac\connectivity_test\FreeRTOS\iar)

   
2. After the workspace is open, select the project
3. Click the Make button to build the project

Download and Run the application demo

1. Connect your FRDM-KW41Z board to your PC
2. Click on the Download and Debug button (green arrow located on the toolbar)
3. Once the project has loaded, the debugger should stop at main(). Open a Terminal Emulator program and open a session to your FRDM-KW41Z COM port. Configure the terminal with these settings:
   • 115,200 baud rate
   • No parity
   • 8 data bits
   • 1 stop bit
4. Click the Go button to resume operation
5. The following output will be displayed in the serial terminal. If you don't see this output, verify your terminal settings and connections
6. Refer to <connectivitysoftware_install_folder>\docs\wireless\SMAC\MKW41Z SMAC Demo Applications User's Guide.pdf document for instructions on how to run all the demo applications

Import the MCUXpresso SDK

1. Open up the MCUXpresso IDE
2. Switch to the Installed SDKs view within the MCUXpresso IDE window
3. Open Windows Explorer, and drag and drop the FRDM-KW41Z SDK (unzipped) file into the "Installed SDKs" view
4. You will get the following pop-up. Click OK to continue the import:
5. The installed SDK will appear in the Installed SDKs view as shown below:

Build an Example Application

The following steps will guide you through opening the SMAC example.

1. Find the Quickstart Panel in the lower left-hand corner
2. Then click on Import SDK examples(s)
3. Click on the frdmkw41z board to select that you want to import an example that can run on that board, and then click Next
4. Use the arrow button to expand the "wireless_examples" category, and then under the 'SMAC' category expand the 'connectivity_test' project and select the 'freertos' version of the project. To use the UART for printing (instead of the default semihosting), clear the "Enable semihost" checkbox under the project options. Then, click Next
5. On the Advanced Settings wizard, clear the checkbox "Redirect SDK "PRINTF" to C library "printf"" in order to use the MCUXpresso SDK console functions for printing instead of generic C library ones. Then, click Finish
6. Now, build the project by clicking on the project name and then in the Quickstart Panel click on Build
7. You can see the status of the build in the Console tab

Run an Example Application

1. Now, that the project has been compiled, you can now flash it to the board and run it
2. Make sure that the FRDM-KW41Z board is plugged in, and click in the Quickstart Panel click on "Debug 'frdmkw41z_wireless_examples_smac_connectivity_test_freertos' [Debug]"
3. MCUXpresso IDE will probe for connected boards and should find the JLink debug probe that is part of the integrated OpenSDA circuit on the FRDM-KW41Z. Click on OK to continue
4. You may see the following message if this is your first debug with JLink of the day. Click on the checkbox at the bottom not to display the message again, and then click on Accept
5. The firmware will be downloaded to the board and the debugger started
6. Hit the Terminate icon to stop the debugger
7. Now, disconnect the board, and connect the second FRDM-KW41Z board. Follow the same debugger steps to flash the connectivity software to that board so that both boards have the same firmware on them
8. Now, with both boards connected, open a Terminal Emulator program and open a session to your FRDM-KW41Z COM port for each board. Configure the terminal with these settings:
   • 115,200 baud rate
   • No parity
   • 8 data bits
   • 1 stop bit
9. Hit the reset button on both boards
10. The following output will be displayed in each of the two serial terminals. If you don't see this output, verify your terminal settings and connections
11. Refer to <mcuxpresso sdk directory>\docs\wireless\SMAC\MKW41Z SMAC Demo Applications User's Guide.pdf document for instructions on how to run all the demo applications

These steps show how to:

1. Load and build the demo application in IAR Embedded Workbench
2. Download and run the demo application

The example used below is for the IEEE 802.15.4 "MyWirelessApplication" (mwa) demo, but these steps can be applied to any of the Wireless Connectivity demo applications.

Load and build the coordinator application demo

1. Navigate to the mwa_coordinator IAR workspace (located at <install_dir>\boards\frdmkw41z\wireless_examples\ieee802_15_4\mwa_coordinator\FreeRTOS\iar)
2. After the workspace is open, select the project
3. Click the Make button to build the project

Download the coordinator application demo

1. Connect your FRDM-KW41Z board to your PC
2. Click on the Download and Debug button (green arrow located on the toolbar)
3. Once the project has loaded, the debugger should stop at main(). At this point, we need to program an end device. So, terminate this debug session by clicking the terminate button shown in the figure below
4. Unplug this board and connect a second FRDM-KW41Z board

Load and build the end device application demo

1. Navigate to the mwa_end_device IAR workspace (located at <install_dir>\boards\frdmkw41z\wireless_examples\ieee802_15_4\mwa_end_device\FreeRTOS\iar)
2. After the workspace is open, select the project
3. Click the Make button to build the project

Download the coordinator application demo

1. Connect your second FRDM-KW41Z board to your PC (if not done so already)
2. Click on the Download and Debug button (green arrow located on the toolbar)
3. Once the project has loaded, the debugger should stop at main(). At this point, we need to run the coordinator and end device together. So, terminate this debug session by clicking the terminate button shown in the figure below
4. Unplug this board and connect both boards to your host PC

Run the coordinator application demo

1. Open a Terminal Emulator program and open a session to one of the FRDM-KW41Z COM ports
   • 115,200 baud rate
   • No parity
   • 8 data bits
   • 1 stop bit
2. Open a second Terminal Emulator program and open a session to the other FRDM-KW41Z COM port. Configure the terminal with these settings:
   • 115,200 baud rate
   • No parity
   • 8 data bits
   • 1 stop bit
3. Press the reset button on both boards
4. The coordinator device should display the following screen:
5. The end device should display the following screen:
6. Press any switch on the coordinator board first. The screen should then display the following:
7. Then, press any switch on the end device board. The end device should then connect and display the following screen
8. You should now be able to type characters into either terminal and see the characters echoed in the opposite terminal
9. Refer to <connectivitysoftware_install_folder>\docs\wireless\IEEE 802.15.4\ IEEE 802.15.4 MAC Demo Applications User's Guide.pdf document for instructions on how to run all the demo applications

Import the MCUXpresso SDK

1. Open up the MCUXpresso IDE
2. Switch to the Installed SDKs view within the MCUXpresso IDE window
3. Open Windows Explorer, and drag and drop the FRDM-KW41Z SDK (unzipped) file into the "Installed SDKs" view
4. You will get the following pop-up. Click OK to continue the import:
5. The installed SDK will appear in the Installed SDKs view as shown below:

Build an Example Application

The following steps will guide you through opening the IEEE 802.15.4 example.

1. Find the Quickstart Panel in the lower left-hand corner
2. Then, click on Import SDK examples(s)
3. Click on the frdmkw41z board to select that you want to import an example that can run on that board, and then click Next
4. Use the arrow button to expand the "wireless_examples" category, and then under the 'ieee_802_15_4' category expand the 'mwa_coordinator' project and select the 'freertos' version of the project. To use the UART for printing (instead of the default semihosting), clear the "Enable semihost" checkbox under the project options. Then, click Next
5. On the Advanced Settings wizard, clear the checkbox "Redirect SDK "PRINTF" to C library "printf"" in order to use the MCUXpresso SDK console functions for printing instead of generic C library ones. Then, click Finish
6. Now, build the project by clicking on the project name and then in the Quickstart Panel click on Build
7. You can see the status of the build in the Console tab

Download the coordinator device application demo

1. Now that the project has been compiled, you can now flash it to the board and run it
2. Make sure that the FRDM-KW41Z board is plugged in, and click in the Quickstart Panel click on "Debug "frdmkw41z_wireless_examples_ieee_802_15_4_maw_coordinator_freertos" [Debug]"
3. MCUXpresso IDE will probe for connected boards and should find the JLink debug probe that is part of the integrated OpenSDA circuit on the FRDM-KW41Z. Click OK to continue
4. You may see the following message if this is your first debug with JLink of the day. Click on the checkbox at the bottom not to display the message again, and then click on Accept
5. The firmware will be downloaded to the board and the debugger started
6. At this point, we need to program an end device. So, terminate this debug session by clicking the Terminate button shown in the figure below. Then unplug this board, and plug up your second board

Download the end device application demo

1. Connect your second FRDM-KW41Z board to your PC (if not already done)
2. Import the wireless_demos → ieee_802_15_4 → mwa_end_device_freertos demo using the same steps as you did for the coordinator demo
3. Build and load the end device demo using the same steps as before so that the 2nd FRDM-KW41Z has this firmware on it
4. Stop the debugger

Run the coordinator application demo

1. Open a Terminal Emulator program and open a session to one of the FRDM-KW41Z COM ports. Configure the terminal with these settings:
   • 115,200 baud rate
   • No parity
   • 8 data bits
   • 1 stop bit
2. Open a second Terminal Emulator program and open a session to the other FRDM-KW41Z COM port. Configure the terminal with these settings:
   • 115,200 baud rate
   • No parity
   • 8 data bits
   • 1 stop bit
3. Press the reset button on both boards
4. The coordinator device should display the following screen:
5. The end device should display the following screen:
6. Press any switch on the coordinator board first. The screen should then display the following:
7. Then, press any switch on the end device board. The end device should then connect and display the following screen
8. You should now be able to type characters into either terminal and see the characters echoed in the opposite terminal
9. Refer to <mcuxpresso sdk directory>\docs\wireless\IEEE 802.15.4\IEEE 802.15.4 MAC Demo Applications User's Guide.pdf document for instructions on how to run all the demo applications

These steps show how to:

1. Load and build the demo application in IAR Embedded Workbench
2. Download and run the demo application

The example used below is for the Generic FSK Connectivity Test demo, but these steps can be applied to any of the Wireless Connectivity demo applications.

Load and build the application demo

1. Navigate to the Connectivity Test IAR workspace (located at <install_dir>\boards\frdmkw41z\wireless_examples\genfsk\connectivity_test_genfsk\FreeRTOS\iar)
2. After the workspace is open, select the project
3. Click the Make button to build the project

Download and Run the application demo

1. Connect your FRDM-KW41Z board to your PC
2. Click on the Download and Debug button (green arrow located on the toolbar)
3. Once the project has loaded, the debugger should stop at main(). Open a Terminal Emulator program and open a session to your FRDM-KW41Z COM port. Configure the terminal with these settings:
   • 115,200 baud rate
   • No parity
   • 8 data bits
   • 1 stop bit
4. Click the Go button to resume operation
5. The following output will be displayed in the serial terminal. If you don't see this output, verify your terminal settings and connections
6. Refer to <connectivitysoftware_install_folder> \docs\wireless\GENFSK\Generic FSK Link Layer Quick Start Guide.pdf document for more information on this demo application

Import the MCUXpresso SDK

1. Open up the MCUXpresso IDE
2. Switch to the Installed SDKs view within the MCUXpresso IDE window
3. Open Windows Explorer, and drag and drop the FRDM-KW41Z SDK (unzipped) file into the "Installed SDKs" view
4. You will get the following pop-up. Click OK to continue the import:
5. The installed SDK will appear in the Installed SDKs view as shown below:

Build an Example Application

The following steps will guide you through opening the GenFSK example.

1. Find the Quickstart Panel in the lower left-hand corner
2. Then, click on Import SDK examples(s)
3. Click on the frdmkw41z board to select that you want to import an example that can run on that board, and then click Next
4. Use the arrow button to expand the "wireless_examples" category, and then under the 'genfsk' category expand the 'connectivity_test' project and select the 'freertos' version of the project. To use the UART for printing (instead of the default semihosting), clear the "Enable semihost" checkbox under the project options. Then, click Next
5. On the Advanced Settings wizard, clear the checkbox "Redirect SDK "PRINTF" to C library "printf"" in order to use the MCUXpresso SDK console functions for printing instead of generic C library ones. Then click Finish
6. Now, build the project by clicking on the project name and then in the Quickstart Panel click on Build
7. You can see the status of the build in the Console tab

Run an Example Application

1. Now that the project has been compiled, you can now flash it to the board and run it
2. Make sure that the FRDM-KW41Z board is plugged in, and click in the Quickstart Panel click on "Debug "frdmkw41z_wireless_examples_genfsk_connectivity_test_freertos" [Debug]"
3. MCUXpresso IDE will probe for connected boards and should find the JLink debug probe that is part of the integrated OpenSDA circuit on the FRDM-KW41Z. Click OK to continue
4. You may see the following message if this is your first debug with JLink of the day. Click on the checkbox at the bottom not to display the message again, and then click on Accept
5. The firmware will be downloaded to the board and the debugger started
6. Hit the Terminate icon to stop the debugger
7. Now, disconnect the board, and connect the second FRDM-KW41Z board. Follow the same debugger steps to flash the connectivity software to that board so that both boards have the same firmware on them
8. Now, with both boards connected, open a Terminal Emulator program and open a session to your FRDM-KW41Z COM port for each board. Configure the terminal with these settings:
   • 115,200 baud rate
   • No parity
   • 8 data bits
   • 1 stop bit
9. Hit the reset button on both boards
10. The following output will be displayed in each of the two serial terminals
11. Refer to <mcuxpresso sdk directory>\docs\wireless\GENFSK\Generic FSK Link Layer Quick Start Guide.pdf document for more information on this demo application

The following steps will guide you through creating a simple Thread network. A hybrid Bluetooth Low Energy + Thread project will be loaded onto the 1st board, so that the board can be controlled via a Bluetooth smartphone application. While a Thread-only project will be loaded onto the 2nd board and controlled via a serial terminal.

Build a Hybrid Bluetooth Low Energy + Thread Application

1. Navigate to the Hybrid Bluetooth Low Energy Thread Router workspace (located at <install_dir>\boards\frdmkw41z\wireless_examples\hybrid\ble_thread_router_wireless_uart\freertos\iar)
2. After the workspace is open, select the project
3. Click the Make button to build the project

Download and Run the application demo

1. Connect the first FRDM-KW41Z board to your PC
2. Click on the Download and Debug button (green arrow located on the toolbar)
3. You may see the following message if this is your first debug with JLink of the day. Click on the checkbox at the bottom not to display the message again, and then click on Accept
4. The firmware will be downloaded to the board and the debugger started
5. Right now we only want to load the firmware to the first board, so hit the Terminate icon to stop the debugger

Download the Thread router application demo to the 2nd board

The Hybrid board needs a Thread node to communicate with, so Thread firmware needs to be loaded onto the second board. The Router Eligible End Device project will be loaded onto board #2.

1. Unplug the first FRDM-KW41Z board and plug-in the second FRDM-KW41Z board to your PC
2. Navigate to the Router Eligible End Device project workspace (located at <install_dir>\boards\frdmkw41z\wireless_examples\thread\router_eligible_device\freertos\iar)
3. Build and flash the Router Eligible End Device demo using the same steps as before so that the 2nd FRDM-KW41Z has the thread_router firmware loaded onto it
4. Stop the debugger

Run the hybrid demo

1. Open a Terminal Emulator program and open a session to your FRDM-KW41Z COM port that has the thread_router_eligible project firmware on it (board #2). Configure the terminal with these settings:
   • 115,200 baud rate
   • No parity
   • 8 data bits
   • 1 stop bit
2. Hit the Reset button on board #2, which can be found near where the USB cable is plugged in. You should see the following on the terminal:
3. Plug-in board #1 that has the Hybrid Bluetooth Low Energy + Thread firmware loaded on it, so that both boards are now connected
4. Open the Kinetis Bluetooth Low Energy Toolbox application on your mobile device and click on the Thread Shell function
5. The Kinetis Bluetooth Low Energy Toolbox application should start scanning and find the FRDM-KW41Z board (NXP_THR). Select the NXP_THR device
6. The Kinetis Bluetooth Low Energy Toolbox should now be connected to the device. Using the keyboard on your mobile app that appears, you can type commands to the FRDM-KW41Z device. Type 'help' to see the list of possible commands. Outputs from the FRDM-KW41Z board should appear in the app as well
7. Start a new Thread network by typing 'thr create' or by selecting that command in the Shortcuts menu
8. Inside the Tera Term connection to the second board (that is just running Thread), join this new network by typing 'thr join'
9. Take note of the ML64 address listed in the terminal for R2 by typing 'ifconfig'

10. Inside the smartphone app terminal, type in the command to toggle the LED

    coap CON POST <ip_address>/led toggle

    
11. Refer to <mcuxpresso sdk directory>\docs\wireless\Thread\Kinetis Thread Stack Demo Applications User's Guide.pdf document for more information on this demo application

The following steps will guide you through creating a simple Thread network. A hybrid Bluetooth Low Energy + Thread project will be loaded onto the 1st board, so that the board can be controlled via a Bluetooth smartphone application. While a Thread-only project will be loaded onto the 2nd board and controlled via a serial terminal.

Import the MCUXpresso SDK

1. Open up the MCUXpresso IDE
2. Switch to the Installed SDKs view within the MCUXpresso IDE window
3. Open Windows Explorer, and drag and drop the FRDM-KW41Z SDK (unzipped) file into the "Installed SDKs" view
4. You will get the following pop-up. Click OK to continue the import:
5. The installed SDK will appear in the Installed SDKs view as shown below:

Build a Hybrid Bluetooth Low Energy + Thread Application

The following steps will guide you through opening the hybrid example. This project will be loaded to one board, while another project will be loaded on the 2nd board.

1. Find the Quickstart Panel in the lower left-hand corner
2. Then, click on Import SDK examples(s)
3. Click on the frdmkw41z board to select that you want to import an example that can run on that board, and then click Next
4. Use the arrow button to expand the "wireless_examples" category, and then under the 'hybrid' category expand the 'ble_thread_router_wireless_uart' project and select the 'freertos' version of the project. To use the UART for printing (instead of the default semihosting), clear the "Enable semihost" checkbox under the project options. Then, click Next
5. On the Advanced Settings wizard, clear the checkbox "Redirect SDK "PRINTF" to C library "printf"" in order to use the MCUXpresso SDK console functions for printing instead of generic C library ones. Then click Finish
6. Now, build the project by clicking on the project name and then in the Quickstart Panel click on Build
7. You can see the status of the build in the Console tab

Download the hybrid application demo to the 1st board

1. Now that the project has been compiled, you can now flash it to the board and run it
2. Make sure that the FRDM-KW41Z board is plugged in, and click in the Quickstart Panel click on "Debug "frdmkw41z_wireless_examples_hybrid_ble_thread_router_wireless_uart_freertos" [Debug]"
3. MCUXpresso IDE will probe for connected boards and should find the JLink debug probe that is part of the integrated OpenSDA circuit on the FRDM-KW41Z. Click OK to continue
4. You may see the following message if this is your first debug with JLink of the day. Click on the checkbox at the bottom not to display the message again, and then click on Accept
5. The firmware will be downloaded to the board and the debugger started
6. Right now, we only want to load the firmware to the first board, so hit the Terminate icon to stop the debugger

Download the Thread router application demo to the 2nd board

The Hybrid board needs a Thread node to communicate with, so Thread firmware needs to be loaded onto the second board. The Router Eligible End Device project will be loaded onto board #2.

1. Unplug the first FRDM-KW41Z board and plug-in the second FRDM-KW41Z board to your PC
2. Import the wireless_demos → thread → router_eligible_device → freertos demo using the same steps as you did for the hybrid demo
3. Build and load the end device demo using the same steps as before so that the 2nd FRDM-KW41Z has the thread_router firmware on it
4. Stop the debugger

Run the hybrid demo

1. Open a Terminal Emulator program and open a session to your FRDM-KW41Z COM port that has the thread_router_eligible project firmware on it (board #2). Configure the terminal with these settings:
   • 115,200 baud rate
   • No parity
   • 8 data bits
   • 1 stop bit
2. Hit the Reset button on board #2, which can be found near where the USB cable is plugged in. You should see the following on the terminal:
3. Plug-in board #1 that has the Hybrid Bluetooth Low Energy + Thread firmware loaded on it, so that both boards are now connected
4. Open the Kinetis Bluetooth Low Energy Toolbox application on your mobile device and click on the Thread Shell function
5. The Kinetis Bluetooth Low Energy Toolbox application should start scanning and find the FRDM-KW41Z board (NXP_THR). Select the NXP_THR device
6. The Kinetis Bluetooth Low Energy Toolbox should now be connected to the device. Using the keyboard on your mobile app that appears, you may type commands to the FRDM-KW41Z device. Type 'help' to see the list of possible commands. Outputs from the FRDM-KW41Z board should appear in the app as well
7. Start a new Thread network by typing 'thr create' or by selecting that command in the "Shortcuts" menu
8. Inside the Tera Term connection to the second board (that is just running Thread), join this new network by typing 'thr join'
9. Take note of the ML64 address listed in the terminal for R2 by typing 'ifconfig'

10. Inside the smartphone app terminal, type in the command to toggle the LED

    coap CON POST <ip_address>/led toggle

    
11. Refer to <mcuxpresso sdk directory>\docs\wireless\Thread\Kinetis Thread Stack Demo Applications User's Guide.pdf document for more information on this demo application

1. Open the MCUXpresso IDE
2. Click Import SDK Examples from the QuickStart Panel
3. Select the FRDM-KW41Z board in the Import Wizard. Then, select Next
4. Type "LED" into the search bar, and select the "led_output" project under the GPIO driver example. Then, select Next. This will create a new standalone copy of this LED project and put it into the MCUXpresso workspace. To use the UART for printing (instead of the default semihosting), clear the "Enable semihost" checkbox under the project options. Then, click Next
5. On the Advanced Settings wizard, clear the checkbox "Redirect SDK" "PRINTF" to C library "printf"" in order to use the MCUXpresso SDK console functions for printing instead of generic C library ones. Then click Finish
6. Click on the "led_output" project in the Project Explorer View and build, compile, and run the demo as described previously
7. You should see a red LED blinking on the board
8. Terminate the debug session

1. Open the MCUXpresso Config Tools
2. In the wizard that comes up, browse to the place where the MCUXpresso SDK was unzipped, and then select the "Clone an example project" radio button and click Next
3. Select the project to clone. For this example, we want to use the LED project. You can filter for this by typing "LED" in the filter box and then selecting the "gpio/led_output" project. Then click Next
4. Then, select the directory you want to place the cloned project, give it a name and select the IDE to use. Note that only IDEs that were selected in the online SDK builder when the SDK was built will be available. Then click Finish
5. After cloning go to the directory you selected and open up the project for your IDE. Import, compile, and run the project as done in previous sections
6. You should see a red LED blinking on the board
7. Terminate the debug session

1. Open MCUXpresso Config Tools
2. The wizard will ask if you want to start development with or without an SDK. Choose to start development with the SDK and that we want to create a new configuration. Use the "Browse" button to navigate to the location of your unzipped SDK installation
3. Select the SDK top-level folder from your file system. Select OK
4. The wizard asks to create a new configuration or clone an example project. We will Create a new configuration that will be based on the "led_output" project settings from the SDK. Select Next to continue
5. Search for the led_output example by typing "LED" in the search bar. Select the led_output example and press Finish
6. Open the Pins Tool by selecting Tools → Pins from the toolbar
7. The Pins Tool should now display the pin configuration for the led_output project
8. In the Pins view, click the "Show Routed/All Pins" checkbox to see all the routed pins. Routed pins have a check in a green box next to the pin name. The functions selected for each routed pin are highlighted in green in the table
9. In the current configuration, PTC1 is routed as a GPIO to toggle the red LED. Let's disable PTC1, and change the MUX setting of PTA18 to use its GPIO functionality to drive the blue LED
10. Disable PTC1 (red LED) as a GPIO by clicking the PTC1 field under the GPIO column. The pin will then be disabled (pin will no longer have check in box) and thus disappear from the list
11. Now, route PTA18 as a GPIO. First, deselect the "Show Routed All/Pins" so that all the pins are displayed again. Then, search PTA18 in the Pins view. Finally, click the box under the GPIO column. The box will highlight in green, and a check will appear next to the pin
12. The updated view will appear as below once you clear the filtered text. Note that PTB21 also appears in the Routed Pins tab and PTB22 has been removed. The pin_mux.c file has been updated to reflect the change as well

13. Now, export the pin_mux.c and pin_mux.h files by clicking on the Sources tab on the right side to get to the Sources view, and selecting the export icon

14. Select the directory to export the pin_mux.c and pin_mux.h files. In this example export to the "board" folder in the led_output project in the workspace that was created in the previous section (i.e. C:\nxp_workspace\frdmkw41z_driver_examples_gpio_led_output\board). Select Finish
15. Click Yes to replace the existing pin_mux.c and pin_mux.h files
16. We'll use MCUXpresso IDE for the rest of the instructions but the same steps can be done in other 3rd party IDEs. Under the "led_output" project, double-click the gpio_led_output.c file in the source folder to display the file in the editor. Notice that the macros used in the GPIO driver functions refer to the BOARD_LED (i.e. red LED)
17. Change the defines for BOARD_LED_GPIO to the "GPIOA" and the BOARD_LED_GPIO_PIN to "18"
18. Build and download the project as done in the previous section
19. Run the application. You should now see the blue LED blinking!
20. Terminate the debug session

1. Open MCUXpresso Config Tools
2. Open the Clocks Tool from the toolbar: Tools → Clocks
3. The clock configuration for the 'led_output' project will appear in the Clocks Tool:
4. Switch to the Clocks Diagram view by clicking the tab in the upper left corner, and ensure that the BOARD_BootClockRUN clock mode is being displayed by clicking the tab in the lower left corner
5. Change the core clock frequency by clicking in the Core Clock field and typing "10 MHz". You'll see all the associated clock frequencies automatically change as well then
6. Now, open the "Sources" tab and export the clock_config.c and clock_config.h files
7. Select the directory to export the pin_mux.c and pin_mux.h files. In this example export to the “board” folder in the led_output project in the workspace that was created in the previous section (i.e. C:\nxp_workspace\frdmkw41z_driver_examples_gpio_led_output\board). Select Finish
8. Press Yes to replace the existing clock_config.c and clock_config.h files
9. Now, open the LED project in your IDE, build, download, and run the project as you did before
10. The blue LED should now be blinking at a much slower rate