# 2. Hardware Overview

SMHUB is a **Linux-based modular hub** designed to unify connectivity, automation, and control across multiple smart home and IoT standards. Its hardware architecture combines **high-performance networking, multiple radios, built-in peripherals, and modular power options**.

## 2.1 Core System

- **Processor:** 2 separate cores: C906@1GHz (for Linux) + C906@700MHz (for RTOS).  
    *C906 is an ultra-high-efficiency processor compatible with the RV64IMA\[F\]C\[V\] instruction set. It is one of the industry's first mass-produced processors supporting the RISC-V vector extension.*
- **NPU (Neural Processing Unit):** 0.5 TOPS@INT8.
- **Memory:** 512 MB RAM.
- **Storage:** Onboard eMMC storage plus **microSD slot** for expansion.
- **Operating System:** Embedded Linux with Node.js runtime, supporting smart applications such as Zigbee2MQTT, Matterbridge, Node-RED, and custom Node.js/Python services.

## 2.2 Networking

- **Ethernet:** Integrated RJ-45 port for wired backbone connectivity.
- **Wi-Fi:**
    
    
    - Dual-band **2.4 GHz and 5 GHz** support.
    - Can operate in **Access Point** mode or **Client** mode.
    - CLI setup available, with web UI configuration in development.
- **Bluetooth:**
    
    
    - **Bluetooth 5.0** compliant.
    - Supports **Bluetooth Low Energy (BLE)** for pairing, sensors, and beacons.
    - Available for integrations and custom applications.

## 2.3 Radios

- **Zigbee (CC26xx)** → dedicated radio for Zigbee networks, fully compatible with Zigbee2MQTT.
- **Thread (EFR32MG series)** → native support for Thread and OpenThread Border Router (OTBR).
- **EFR32ZG23 Expansion Module** → provides **Sub-GHz communications including Z-Wave**, integrated via UART3 with dedicated reset, flash, and LED lines.

## 2.4 Expansion Modules

- **UPS Module (SM-HUB UPS)**
    
    
    - Powered by **18650 Li-ion battery cells**.
    - Charging via TP5100.
    - Step-up/step-down converters deliver **5 V, 3.3 V, and 1.8 V rails**.
    - **INA226 sensor** monitors voltage and current for telemetry.
    - Solar/DC charging input supported.
- **PoE Module (SM-HUB PoE)**
    
    
    - 802.3af compliant (Power over Ethernet).
    - Converts Ethernet-supplied power to regulated 5 V.
    - Surge and ESD protection integrated.
    - “Power-check” signals exposed for system monitoring.
- **4G/LTE Module (SM-HUB 4G)**
    
    
    - Based on **SIM7672G modem** with **GNSS (GPS/GLONASS)**.
    - NanoSIM slot with SIM detect.
    - Interfaces: main UART, USB, debug UART.
    - LTE and GNSS antenna connectors.
    - Power and network LED indicators.

## 2.5 Built-in Peripherals

- **LEDs:**
    
    
    - **12 × WS2812B addressable RGB LEDs** – configurable for system visualization, animations, or Ambilight effects.
    - **4 × service LEDs** – indicating power, network, and radio activity.
- **Buttons:**
    
    
    - **Reset button**.
    - **Pairing/Function button**.
    - **User-configurable button**.
- **Audio Output:**
    
    
    - **3.5 mm audio jack**.
    - Supports system notifications, alerts, or media playback.
- **Buzzer:**
    
    
    - Integrated piezoelectric buzzer.
    - Usable for system alerts, notifications, or user automation rules.
- **IR Modules:**
    
    
    - **IR transmitter** for controlling TVs, AC units, and other IR devices.
    - **IR receiver** for capturing signals from existing remotes.

## 2.6 Power Architecture

- **Primary Power:** USB-C PD input.
- **Optional Power Sources:**
    
    
    - PoE (via PoE module).
    - UPS battery module.
    - Solar/DC input (through UPS module).
- **Smart USB Power Switching:** Automatic host/device detection on USB-C CC lines with integrated FET switching. Prevents reverse powering and ensures safe operation whether SMHUB is supplying power to peripherals or being powered itself.

## 2.7 Expansion & DIY Interfaces

For developers and hardware enthusiasts, SMHUB exposes additional interfaces:

- **GPIO headers** with UART, SPI, and I²C.
- **DIY pinouts** for custom modules, sensors, or experimental expansions.