1.2 Functional Description

The block diagram below illustrates the major connections of the CryptoAuth Trust Platform. For additional details, refer to the board schematics referenced in Hardware Documentation.

Figure 1-2. Block Diagram

Main Board Components

  • ATSAMD21E18A: The Microchip SAM D21 is an ARM® Cortex M0+ based microcontroller. The MCU connects to the secure element via I2C. The mikroBUS header has I2C, SPI, UART, GPIO and analog connections to the microcontroller. This enables the possibility of using the CryptoAuth Trust Platform with many types of MikroElektronika Click boards™.
  • Secure Elements:

    The CryptoAuth Trust Platform contains three security ICs, as listed in the table below. Refer to the specific data sheets associated with each of these devices for more details.

    DeviceDefault 7-bit I2C Address8-bit Programmed I2C Address Value(1)
    ATECC608B-TNGTLS0x350x6A
    ATECC608B-TFLXTLS0x360x6C
    ATECC608B-MAHDA0x600xC0
    Note:
    1. This is the I2C_Address byte value programmed into the secure element device.
  • mikroBUS Header: The mikroBUS header is a pre-defined header connection for all the MikroElektronika boards. This lets the user connect many types of Click sensors and add-on boards to the Trust Platform. The Trust Platform supports the following interfaces:
    1. Serial Peripheral Interface (SPI) – Needed to support the TA100 and TA101 cryptography devices but can also support any mikroBUS board with a SPI interface.
    2. I2C – Supports any mikroBUS or click board with an I2C Interface. Boards that are often combined with the Trust Manager are other Microchip mikroBUS cryptography boards, socket boards from mikroElektronica and Microchip and sensor boards used for IoT devices.
    3. SWI - UART – Supports the proprietary Single Wire Interface (SWI) for devices such as the ATECC608 family of devices and the ATSHA204A.
    4. SWI-PWM – Supports the SWI Interface with the Pulse Width Modulated signaling for the Microchip Authentication ICs for the SHA104, SHA105, SHA106, ECC204, ECC206, TA010
  • GPIO Signals: GPIO signals not used for any other purpose can be used as appropriate.
  • DIP Switch: The switch is used to select between the on-board Trust Platform devices and the mikroBUS header. The switches disconnect the SDA lines of the I2C interface to prevent conflict in case two I2C addresses are the same. Both switches can be enabled if all I2C addresses are unique on all devices connected to the board.
    Switch SettingsWhat is Enabled
    SW2_1SW2_2mikroBUS HeaderOn-Board Devices
    ONONYesYes
    OFFONNoYes
    ONOFFYesNo
    OFFOFFNoNo
  • nEDBG Debugger: The debugger is used to program and flash the host MCU. Debug information can also be read back from the host MCU through the debugger interface. When plugged into the system and opened with MPLAB® X IDE, the nEDBG debugger will display with a serial number of MCHP3311xxxxxxxx.
  • USB Hub: The Microchip USB2422 is a dual-port USB hub. The hub passes data between the upstream port and the downstream devices. The downstream devices are the debugger and the host MCU.