Minimal Board Design

Expansion Board Minimum Requirements:

  1. Method for connecting Intel® Joule™ module to expansion board:
    The module must be securely mounted to an expansion board in a method that maintains full engagement of the board-to-board interface connectors. See Module Retention for more details.
  2. Method to provide +VSYS power to the module:
    The module requires a +VSYS source routed through 12 pins, 6 on each board-to-board connector, which must all be connected in common to balance the current path.
    Connect +VSYS to VDCIN_SENSE or USB +VBUS to VBUS_SENSE to trigger a module boot.
    Voltage minimum: 3.6 V, typical: 4.2 V, maximum: 5.25 V, with a current capability of 4 A
  3. Required strapping of module pins:
    The module pin strappings in Required Straps must be implemented for boot during the rising edge of PMIC_PWRGOOD (J6, pin 33). See also Boot Strap Signal Isolation for a recommended isolation circuit.
    Module strap pins can be left unconnected if not used.

Expansion Board Recommendations:

  1. Power button (recommended, preferred on all designs):
    Connect an active, low-power button to J6 pin 9 to trigger a reset or to power cycle the board.
  2. DnX button (high importance, include if BIOS flashing support is needed. Add a test point for access if the DnX button is not included.):
    Connect an active, high (+VDD1) signal to J6, pin 78, to initiate a download and execute a routine that updates the BIOS through the USB 2.0, port 0. This DnX button signal is the only way to initiate the download and execute the update process.
  3. USB 2.0 device connector routed to port 0 to enable DnX BIOS updates.
  4. UART debugging (critical, preferred on all designs):
    Include a method to access UART port 2 on the module during boot, to collect debug information. This is the only way to access debug messages generated during the power on and boot sequences.
  5. External EEPROM to hold board identification and manufacturing data.
  6. USB 3.0 host connector for general purpose device use; recommend implementing USB host support.
  7. Real-Time Clock (RTC) backup power source (optional, implement if RTC support needed):
    A backup power source is required for the RTC to operate robustly; this prevents RTC data losses during unexpected power loss. The most common solution is a non-rechargeable, coin-cell battery connected to +VRTC at module connector J6, pin 11. +VRTC voltage range is from 2.05 V to 3.3 V.
  8. HDMI display connector with proper level conditioning appropriate for module.

 

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