1.20 PIT64B Periodic Interrupt

This application shows how to use PIT64B counter in Interrupt mode.

Description

This application toggles an LED based on the PIT64B interrupt. Every time the PIT64B counter expires the LED toggles.

Downloading and Building the Application

To clone or download this application from Github, go to the main page of this repository and then click Clone button to clone this repository or download as zip file. This content can also be downloaded using content manager by following these instructions.

Path of the application within the repository is apps/pit64b/period_change.

To build the application, refer to the following table and open the project using its IDE.

Project NameDescription
sam_a7d65_curiosity.XMPLABX project for SAMA7D65 Curiosity Board
sam_a7d65_curiosity_pro.XMPLABX project for SAMA7D65 Curiosity Pro Board

Setting Up AT91Bootstrap Loader

To load the application binary onto the target device, we need to use at91bootstrap loader. Refer to the at91bootstrap loader documentation for details on how to configure, build and run bootstrap loader project and use it to bootstrap the application binaries.

Setting Up the Hardware

The following table shows the target hardware for the application projects.

Project NameDescription
sam_a7d65_curiosity.XSAMA7D65 Curiosity Board
sam_a7d65_curiosity_pro.XSAMA7D65 Curiosity Pro Board

Setting Up SAMA7D65 Curiosity Board

Setting up the board:
  • Connect the USBA port J3 on the board to the computer using a Type-C USB cable (to power the board)

Setting Up SAMA7D65 Curiosity Pro Board

Setting up the board:
  • Connect the USBA port J1 on the board to the computer using a Type-C USB cable (to power the board)

Running the Application

  1. Build and run the application using its IDE.
  2. Press USER switch to start/stop timer.
  3. LED toggles at a fixed rate when timer is on and stops toggling when timer is off.
  4. Press RESET switch to change the timer period.
  5. When timer period is changed LED toggle rate is changed.
  6. Timer period cycles between 250 ms, 500 ms, 750 ms and 1000 ms.
Following table provides details of switch and LED names:
BoardUSER SWRESET SWLED
SAMA7D65 Curiosity BoardSW2SW4RGB_LED (Blue)
SAMA7D65 Curiosity Pro BoardSW3SW4RGB_LED (Blue)