Boot Configurations; Generating The Image File - Enclustra Mars AX3 User Manual

4 Boot Configurations

Once a software application has been developed and tested, this can be used to build a boot image for
the module.
The boot image contains the bitstream for programming the FPGA and the software bare-metal appli-
cation.
The entire software program is written into the on-chip memory. Therefore, when the FPGA is configured
with the bitstream, the microprocessor is started and the program is automatically loaded.
For a fast test of the boot configurations, the pre-generated download.bit file may be used to program
the flash memory with the bitstream and the example project, instead of rebuilding the image. You need
to select the file corresponding to the Mars AX3 FPGA module variant. Pre-generated binaries for any
AX3 variant are released on the AX3 Reference Design Github page.
4.0.1

Generating the Image File

Step Description
1 Create the boot image from Xilinx Vitis 2022.1:
1. Right click on the application (e.g. HelloWorld) in the Project Explorer under the system
project (e.g. HelloWorld_system)
2. Select Generate Linker Script
3. Leave all settings as default (see Figure 5) and click Generate
4. Click Yes when asked if you want to overwrite the already existing file
5. Rebuild the project
6. Right click the system project of the application (e.g. HelloWorld_system) and select
Program Device
7. Under the ELF/MEM File to Initialize in Block RAM select the application .elf file to be
written into the FPGA block RAM (see Figure 6)
8. Click Generate
A bitstream file with the application ELF data will be created for example in <workspace>
\HelloWorld\_system\_ide\bootimage\download.bit.
2 Optional - Create the boot image to be written to the QSPI flash
Xilinx Vitis or Enclustra MCT support both .bit and .bin formats for the QSPI flash image, but
the Vivado Hardware Manager supports only .bin and .mcs formats.
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