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# 1.15 Generic Timer Periodic Interrupt

This application shows how to use Generic timer counter in interrupt mode.

## Description

This application toggles an LED based off the Generic Timer interrupt. Every time the Generic Timer counter expires the LED toggles. You can start, stop and change period of the timer counter using push button switches.

## 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/generic_timer/start_stop_period_change.

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

Project Name | Description
--- | ---
sam_a7d65_curiosity.X | MPLABX project for SAMA7D65 Curiosity Board
sam_a7d65_curiosity_pro.X | MPLABX 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 Name | Description
--- | ---
sam_a7d65_curiosity.X | SAMA7D65 Curiosity Board
sam_a7d65_curiosity_pro.X | SAMA7D65 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)

## Running the Application

1. Build and run the application using its IDE.
2. Press SW2 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 SW4 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:

Board | USER | RESET | LED Name
--- | --- | --- | ---
SAMA7D65 Curiosity Board | SW2 | SW4 | RGB_LED (Blue)
SAMA7D65 Curiosity Pro Board | SW3 | SW4 | RGB_LED (Blue)

Rev: C