3.5.2 Getting Started with Harmony v3 Drivers on SAM D21 MCU Using FreeRTOS

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Description

The application reads the current room temperature from the temperature sensor on the I/O1 Xplained Pro Extension Kit. The temperature reading is displayed on a serial console periodically every second. Further, the application writes the temperature readings to EEPROM. When a character is entered on the console, the last five written temperature values are read from the EEPROM and displayed on the console. The LED0 is toggled every time the temperature is displayed on the serial console

Modules/Technology Used

  • Peripheral Modules
    • PORTS
    • SERCOM(I2C)
    • SERCOM(USART)
  • Drivers
    • SERCOM(I2C)
    • USART
  • Third Party Libraries
    • FreeRTOS

Hardware Used

Software/Tools Used

This project has been verified to work with the following versions of software tools:

Refer Project Manifest present in harmony-manifest-success.yml under the project folder firmware/src/config/sam_d21_xpro.

  • Refer the Release Notes to know the MPLAB X IDE and MCC Plugin version.
  • Any Serial Terminal application, such as Tera Term terminal application.

Because Microchip regularly updates tools, occasionally issue(s) could be discovered while using the newer versions of the tools. If the project does not seem to work and version incompatibility is suspected. It is recommended to double-check and use the same versions that the project was tested with. To download original version of MPLAB Harmony v3 packages, refer to document How to Use the MPLAB Harmony v3 Project Manifest Feature (DS90003305).

Setup

  • Verify that the temperature sensor (I/O1 Xplained Pro Extension Kit) is connected to Extension Header 1 (EXT1) on the SAM D21 Xplained Pro Evaluation Kit.
  • The SAM D21 Xplained Pro Evaluation Kit allows using the Embedded Debugger (EDBG) for debugging. Connect the Type-A male to micro-B USB cable to micro-B DEBUG USB port to power and debug the SAM D21 Xplained Pro Evaluation Kit.

Programming Hex File

The pre-built hex file can be programmed by following the below steps.

Steps to program the hex file:
  • Open MPLAB X IDE
  • Close all existing projects in IDE, if any project is opened.
  • Go to File -> Import -> Hex/ELF File.
  • In the Import Image File window,
    1. Create Prebuilt Project,
      • Click the Browse button to select the prebuilt hex file.
      • Select Device as ATSAMD21J18A.
      • Ensure the proper tool is selected under Hardware Tool and click on Next button.
    2. Select Project Name and Folder,
      • Select appropriate project name and folder and click on Finish button
  • In MPLAB X IDE, click on Make and Program Device button to program the device.
  • Follow the steps in Running the Demo section below.

Programming/Debugging Application Project

  • Open the project (samd21_getting_started/firmware/drivers_freertos_sam_d21_xpro.X) in MPLAB X IDE
  • Ensure SAM D21 Xplained Pro is selected as hardware tool to program/debug the application
  • Build the code and program the device by clicking on the Make and Program Device button in MPLAB X IDE tool bar
  • Follow the steps in Running the Demo section below

Running the Demo

  • Open the Tera Term terminal application on the PC (from the Windows Start menu by pressing the Start button).
  • Change the baud rate to 115200.
  • The user should see the temperature values (in °F) being displayed on the terminal every second, as shown below.
  • Notice the LED0 blinking at one second rate.
  • The user may vary the temperature by placing the finger on the temperature sensor (for a few seconds).
  • Press any key to display the last five written temperature values from the EEPROM.

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