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# 1.5 Clock Configuration

This example application shows how to configure the clock system to run the device at maximum frequency. It also outputs a prescaled clock signal on a GPIO pin for measurement and verification.

## Description

Clock system generates and distributes the clock for the processor and peripherals. This example application shows how to use the clock manager to configure the device to run at the max possible speed. A prescaled clock signal is routed to GPIO pin to measure the frequency and accuracy of the internal device clock.

## 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/clock/clock_config.

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)
- Connect an oscilloscope to clock output Pin 31 of RPi connector

### 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)
- Connect an oscilloscope to clock output Pin 31 of RPi connector

## Running the Application

1. Build and run the application using its IDE.
2. Observe the clock of ~2 MHz on clock output pin.
3. LED should be blinking continuously.

Refer to the following table for clock output pin and LED name for different boards:

Board | Clock Output Pin | LED Name
--- | --- | ---
SAMA7D65 Curiosity Board | Pin 31 (RPi connector) | RGB_LED (Green)
SAMA7D65 Curiosity Pro Board | Pin 31 (RPi connector) | RGB_LED (Green)

Rev: C