1.47 TrustZone Data Flash Scrambling and RTC Tamper Detection - PIC32CMLS00

This example application displays the Data Flash content on a console which is refreshed every seconds. The Data Flash Scrambling and Tamper Erase security features of the Data Flash are enabled.

Description

This demonstrates TrustZone feature and uses two projects viz., Secure and Non-Secure Project that work together on the same MCU and offering security isolation between the Trusted and the Non-trusted resources in the device.

  • Secure project configures the RTC peripheral for tamper detection and SERCOM3 peripheral to display content on console through UART pins.
  • Secure project configures the Secure Data Flash security features (Data Flash Scrambling - Tamper Erase).
  • Non-secure project uses veneers to request from Secure project, to erase Secure Data Flash, fill it with 0xCAFEDECA pattern and display its content on console every seconds. When a Tamper is detected, Non-Secure application is halted and Secure Data Flash content is fully erased.

Components Used

  • Data Flash - Configured in Secure APPLICATION region
  • RTC - Configured as Secure mode
  • PA08 - Configured as Secure pin (RTC Tamper Pin)
  • SERCOM3 - Configured as Secure mode (USART mode)

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 as shown below:
TypePath
Project Groupapps/trustZone/nvmctrl/secure_dataflash_DS_TE_ls00
Secure Projectapps/trustZone/nvmctrl/secure_dataflash_DS_TE_ls00/Secure/firmware
Non-Secure Projectapps/trustZone/nvmctrl/secure_dataflash_DS_TE_ls00/NonSecure/firmware
To build the application, refer to the following table and open the project using its IDE.
Project NameDescription
pic32cm_ls00_cpro_Secure.X

pic32cm_ls00_cpro_NonSecure.X

Secure and Non-secure MPLABX project for PIC32CM LS00 Curiosity Pro Evaluation Kit

Setting Up the Hardware

The following table shows the target hardware for the application projects.

Project NameBoard
pic32cm_ls00_cpro_Secure.X

pic32cm_ls00_cpro_NonSecure.X

PIC32CM LS00 Curiosity Pro Evaluation Kit

Setting Up PIC32CM LS00 Curiosity Pro Evaluation Kit

  • Connect the Debug USB port on the board to the computer using a micro USB cable
  • Short PA08 pin (EXT3, PIN 3) to VCC

Running the Application

  1. Open the Terminal application (Ex.: Tera term) on the computer
  2. Connect to the EDBG Virtual COM port and configure the serial settings as follows:
    • Baud : 115200
    • Data : 8 Bits
    • Parity : None
    • Stop : 1 Bit
    • Flow Control : None
  3. Open the project group in the MPLAB X IDE and set the non-secure project as main project
  4. Build and program the application
  5. The console should display the following Secure Data Flash content:
  1. Tied down the PA08 pin with a jumper (Remove short from VCC and connect it to GND to create a falling edge)
  2. The following Secure Data Flash content should be observed on console, meaning the Secure Data Flash Tamper Erase Row 0 was performed because of RTC Tamper Detection: