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TROPIC01 Firmware

TROPIC01 contains the following FW execution engines:

  • RISC-V CPU,
  • ECC engine or SPECT (these two terms are used interchangeably).

There are multiple kinds of FW running in TROPIC01:

  1. Immutable FW (bootloader). Located in ROM, runs on RISC-V CPU from ROM after power-up, updates or boots the mutable FWs.
  2. RISC-V Mutable FW (CPU FW). Updatable, located in R-memory, runs on RISC-V CPU from RAM, processes L2/L3 communication.
  3. ECC engine mutable FW (ECC engine FW). Updatable, located in R-memory, runs on ECC engine from RAM, helps the RISC-V CPU FW with processing ECC commands (ECC_Key_*, ECDSA/EDDSA_Sign).

Tip

For more detailed information about each FW, refer to the FW Update Application Note.

TROPIC01 Firmware in Libtropic

Libtropic provides not only implementation of the FW update L2 commands, but also the necessary files for updating both the RISC-V and SPECT FW. Refer to:

  1. Firmware Update Files section for more information about the TROPIC01_fw_update_files/ directory.
  2. lt_ex_fw_update.c section (in the Irreversible Examples documentation page) for a practical example, showing how to update TROPIC01's FW using Libtropic.

Firmware Update Files

The TROPIC01_fw_update_files/ directory provides TROPIC01 FW update files in two formats:

  1. C header files (*.h). These are designed to be included and compiled directly into the Host MCU's firmware/application. See Compiling into Libtropic section for more information.
  2. Binary files (*.bin). These can be stored in the Host MCU, loaded at runtime and used to update TROPIC01's FW.

The general structure of the TROPIC01_fw_update_files/ directory is the following: 

TROPIC01_fw_update_files/
├── boot_v_<X_Y_Z>/
│   └── fw_v_<A_B_C>/
│       ├── fw_CPU.h
│       ├── fw_SPECT.h
│       ├── fw_v<A_B_C>.hex32_signed_chunks.bin
│       └── spect_app-v<D_E_F>_signed_chunks.bin
└── convert.py

  • boot_v_<X_Y_Z>/: directories of available FW update files for a given bootloader version <X_Y_Z>.
  • fw_v_<A_B_C>/: directory with RISC-V CPU and SPECT FW update files (in both formats) for a given FW version <A_B_C>. Note that the RISC-V CPU FW and SPECT FW versions can be different.
  • convert.py: Python script for converting firmware binary files into C header files.

Compiling into Libtropic

To select which FW version will be compiled together with Libtropic, the user has to set the following CMake variables (both have a default value):

  1. LT_SILICON_REV: Defines the TROPIC01 silicon revision (e.g. "ACAB"), based on which the correct bootloader version is selected. Refer to the Available Parts section (in the TROPIC01 GitHub repository) to find out the silicon revision of your TROPIC01 chip.
  2. LT_CPU_FW_VERSION: Defines the TROPIC01 FW version (e.g. "1_0_1"), based on which the correct FW update files for both RISC-V CPU and SPECT are selected.