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System Architecture

The Modular Mechanica system is built around two complementary standards that work together to create a flexible and modular robotics platform.

Moducard - The Central Unit​

Moducard serves as the "brain" of the robot, consisting of:

  • Backplane - Main PCB where all cards are inserted
  • Cards - Various functional boards inserted into the backplane

Backplane Features​

The backplane connects and distributes power to all components:

  • DIN41612 connectors for inserting cards
  • Power distribution - 12V standby and Vbat (12-48V)
  • Communication buses - CAN, GPIO, USB
  • Built-in USB hub for each card
  • GPIO lines - GPIO Center (shared), GPIO Left/Right (sibling cards)

Card Types​

The Moducard system includes several types of cards:

  1. CPU Cards - Main computing units (Raspberry Pi CM5, NVIDIA Jetson)
  2. Power Supply Units (PSU) - DC/DC converters with protection
  3. Microcontroller Cards - For control, data acquisition, and specialized functions

MiniModucard System (MMS) - The Peripheral Modules​

MMS serves as the "nerves" and "muscles" of the robot, consisting of:

  • MMS Modules - Main microcontroller boards
  • Hat Modules - Small boards inserted into MMS modules for specific functions

MMS Architecture​

Each MMS module contains a single main microcontroller that manages multiple hat modules connected in towers:

  • Microcontroller: STM32F405 (168 MHz)
  • Power supply: Integrated VIN → 5V converter with wide input voltage range
  • Programming: Built-in ST-Link programmer

Hat Modules​

Hat modules are small boards inserted into MMS modules that contain the actual peripheral electronics:

  • Function-specific - Drivers, sensors, displays, buttons
  • Addressable - Each hat has a unique ID and type
  • Modular - Easy to add/remove functionality

MMS-Link - System Backbone​

MMS-Link is the communication backbone that connects all components:

Physical Connection​

  • RJ45 connector with 8-pin configuration
  • Pin mapping:
    • Pins 1,2: CAN2 Low/High
    • Pins 3: GND
    • Pins 4,5: CAN1 Low/High
    • Pins 6: 12V standby
    • Pins 7,8: USB D-/D+

Communication Protocols​

  • 2× CAN buses (CAN1 + CAN2) - for main communication
  • USB bus - for debugging and programming
  • 12V standby - auxiliary power supply
  • Ground - common reference

Integration Between Moducard and MMS​

The two systems work together through the MMS-Link protocol:

  1. Moducard cards communicate with MMS modules via MMS-Link
  2. MMS modules connect to cards using CAN buses
  3. Communication flows through the backplane to the central unit