SAMA7G54-EK – Configure and Build at91bootstrap to Load an MPLAB® Harmony v3 Application from SD Memory Card

Last modified by Microchip on 2024/06/24 06:29


This training topic describes how to download, configure, and build at91bootstrap to load an MPLAB® Harmony v3 Software Framework application binary image (harmony.bin) from an SD Memory Card to DDR3L SDRAM on the SAMA7G54-EK Evaluation Kit using MPLAB® X Integrated Development Environment (IDE).

Once at91bootstrap has been built, the resulting binary image (boot.bin) can be copied to the SD Memory Card.

at91bootstrap is a second-stage bootloader for Microchip Technology, Arm®-based microprocessors (MPU). For more information, see the "at91bootstrap: A Second Stage Bootloader for Microchip Microprocessors" page.


​This training topic was developed with MPLAB X IDE v6.15 and XC32 v4.30.

Secure Digital Multimedia Card (SDMMC)

The SAMA7G54-EK has a Secure Digital (SD) or MultiMediaCard (MMC) Memory Card slot (J4). It is connected to the Secure Digital MultiMediaCard port 1 (SDMMC1) of the SAMA7G54.

Download at91bootstrap

Create a Project Directory.

For the purposes of this training topic, we’ll name our project directory at91bootstrap. 

Download or clone at91bootstrap version 4.

Download or clone from the Linux4sam GitHub repository.

This training topic was developed with at91bootstrap version 4.0.6 

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Open Project at91bootstrap

From MPLAB X IDE, select File > Open Project… An Open Project dialog is displayed.

Find and select the at91bootstrap project directory.

Click on the Open Project button.  

The at91bootstrap project will be displayed in the Projects pane (upper left) and the at91bootstrap – Dashboard pane (bottom left). 

Open Project

You may receive a Configuration Loading Error. This is due to an older version of the Device Family Pack (DFP) at the time of creating the at91bootstrap project. You will update the DFP to the latest version in the next steps. 

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Configure at91bootstrap Project Properties

Open at91bootstrap Project Properties. 

Open the at91bootstrap Project Properties using one of the following methods: 

  1. In the Projects pane, highlight at91bootstrap and click on the wrench icon in the at91bootstrap - Dashboard
  2. In the Projects pane, right-click on at91bootstrap and select Properties from the menu. 

The Projects Properties – at91bootstrap dialog box opens. 

If you received a Configuration Loading Error in the previous step, you may see a [Resolve] link next to a version of the Device Family Pack (DFP). Highlight the latest DFP and click on the Apply button. This will update the configuration to the latest DFP.  

Project Properties: Conf default

DFP: The Device Family Pack (DFP) contains device-specific support software. The 32-bit MCU and MPU DFPs are maintained by Microchip Technology and are available on GitHub. 

Ensure the Device selected is the SAMA7G54.

Configure the XC32 Compiler.

In the Categories pane, select Makefile

Enter the following text in the Build command and Debug build command boxes: 

make CROSS_COMPILE="C:/Program Files/Microchip/xc32/v4.30/bin/bin/pic32c-" 

Enter the following text in the Clean command box: 

make mplabclean CROSS_COMPILE="C:/Program Files/Microchip/xc32/v4.30/bin/bin/pic32c-" 

Type the version number of the XC32 compiler on your host computer. In this step we are using version 4.30. 

The installation location of the XC compiler versions can be found by selecting from the MPLAB X IDE tool bar: Tools > Options. An Options dialog box will open. Select Embedded from the toolbar and select the Build Tools tab. 

When cutting and pasting, beware of hidden formatting characters. 

Project Properties: makefile

Click on the Apply button.

Configure at91bootstrap to load harmony.bin from the SD Memory Card.
In the Categories pane, select Kconfig and click on the Load button. 

Find the at91bootstrap project directory and select configs directory and then select sama7g5eksd_uboot_defconfig and click on the Open button. 

Project Properties: kconfig

Make the following changes: 

In this step you are taking an existing default configuration and altering it to load the MPLAB Harmony v3 application (harmony.bin) from the SD Memory Card. This makes configuration a little bit easier than starting from scratch. 

Expand Next Software Type and select the Load 4 MB into start of SDRAM radio button.

Project Properties: Next Software Type

Expand Demo Application Image Storage Setup
Set Next Software Image File Name to harmony.bin

Observe the address to load the application 0x66f00000 to The External Ram Address to Load Demo-App Image.  

This value should match the .text load address in the applications linker script (ddram.ld). This value is shown below for the pio_led_on_off_interrupt application. 

Linker for Production: ddram

Click on the Apply and OK buttons.

 This completes the configuration of the at91bootstrap project properties. 

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Build at91bootstrap

Build at91bootstrap. 

Build the at91bootstrap project using one of the following methods: 

  1. In the Projects pane, right-click on at91bootstrap and select Build from the menu 
  2. Click on the Build icon (hammer) in the tool ribbon. 

Observe the build is successful.

Build Successful

Note the location of boot.bin


The boot.bin file is the binary image of at91bootstrap. The boot.bin image can be copied to an SD Memory Card.

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The at91bootstrap has been configured and built to load an MPLAB Harmony v3 Software Framework application from SD Memory Card on the SAMA7G54-EK.

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