SAM9X60-EK – Configure and Build at91bootstrap to Load an MPLAB® Harmony 3 Application from SD Memory Card

Last modified by Microchip on 2023/11/10 10:58


This training topic describes how to download, configure, and build at91bootstrap to load a MPLAB® Harmony 3 Software Framework application binary image (harmony.bin) from SD memory card to DDR2 SDRAM on the SAM9X60-EK Evaluation Kit using the 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 v6.05 and XC32 v4.21.

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 4.0.5.

Open Project at91bootstrap

From MPLAB X IDE, select File > Open Project…

An Open Project dialog is displayed.

Find and select the at91bootstrap project directory.

Open Project

Click on the Open Project button.

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

​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.
Configuration Error

Back to Top

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 DFP. Highlight the latest DFP and click on the Apply button. This will update the configuration to the latest DFP.

Project Properties: Resolve

DFP contains device-specific support software. The 32-bit MCU and MPU DFPs are maintained by Microchip Technology and are available on GitHub.

Back to Top

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/v4.21/bin/bin/pic32c-"

Enter the following text in the Clean command box:

make mplabclean CROSS_COMPILE="C:/Program Files/Microchip/xc32/v4.21/bin/bin/pic32c-"

Project Properties: xc32

Click on the Apply button.

​In the cross-compiler path entered above, type the version number of the XC32 compiler on your host computer. In this step, we are using version 4.21.

​The installation location of the XC compiler versions can be found by selecting from the MPLAB X IDE toolbar: 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.

Back to Top

Configure at91bootstrap to load harmony.bin from SD memory card

In the Categories pane, select Kconfig and click on the Load button.

Find the at91boostrap project directory and select configs directory and then select sam9x60eksd_linux_image_dt_defconfig and click on the Open button.

Project Properties: kconfig

Back to Top

Make the following changes:

In this step you are taking an existing default configuration and altering it to load the MPLAB Harmony 3 application (harmony.bin) from 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: kconfig

Expand Demo Application Image Storage Setup.

Enter the address to load the application 0x23f00000 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 in the accompanying image for the rtt_periodic_timeout application.

Linker for Production: ddram

Enter "harmony.bin" to Next Software Image File Name
Click on the Apply and OK buttons.

This completes the configuration of the at91bootstrap project properties.

Back to Top

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.

Back to Top

Observe the build is successful.

Build Successful

Back to Top

Note the location of boot.bin:


The boot.bin file is the binary image of at91bootstrap. The boot.bin image can now be copied to an SD memory card with a FAT formatted partition. 

Back to Top


The at91bootstrap has been configured and built to load an MPLAB Harmony 3 Software Framework application from SD memory card on the SAM9X60-EK.

Back to Top

What's Next?

Back to Top