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/firmware.

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

Project NameDescription
sam_a7g5_ek.XMPLABX project for SAMA7G54 Evaluation Kit

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_a7g5_ek.XSAMA7G54 Evaluation Kit

Setting Up SAMA7G5 Evaluation Kit

SETTING UP THE BOARD
  • Connect the Debug USB port on the board to the computer using a micro USB cable
  • Connect an oscilloscope to clock output pin

Running the Application

  1. Build and run the application using its IDE
  2. Observe the clock of ~10 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:
BoardClock Output PinLED Name
SAMA7G54 Evaluation KitPin PB5 (SCK pin on Mikrobus1 connector)RGB_LED (Blue)