S0 Base Board

The S0 Base Board is a modular expansion board designed to power and extend the functionality of the S0 compute module. It integrates critical components for industrial IoT and smart metering applications, making it ideal for professional deployments.

Overview

The Base Board transforms the S0 module into a complete gateway solution by adding:

• Wired Ethernet connectivity
• M-Bus transceiver for utility metering
• SD card for local data logging
• Robust power management with backup
• Industrial-grade mounting options

Hardware Specifications

Core Components

W5500 Ethernet Controller

• SPI-based Ethernet connectivity
• Reliable wired network for industrial environments
• Suitable for installations without wireless coverage
• Low-power operation

TSS721A M-Bus Transceiver

• UART-based interface for M-Bus communication
• Smart metering and utility integration
• Compatible with standard M-Bus devices
• Screw terminal wiring

SD Card Slot

• Local data logging for offline applications
• Edge data buffering
• Historical data storage
• FAT filesystem support

Power Management

Power Input

• 24V DC input via screw terminal
• Wide input voltage range
• Overcurrent protection
• Reverse polarity protection

Battery Backup

• JST connector for battery
• Onboard charging circuit
• Automatic switchover
• Power outage resilience

Physical Specifications

• Standard pin headers for S0 module
• DIN-rail mountable
• Compact form factor
• Industrial-grade PCB

Enhanced Capabilities

When S0 is connected to the Base Board, the gateway gains:

Wired Connectivity

• Ethernet: Reliable SPI-based networking via W5500
• M-Bus: Direct connection to wired utility meters
• Redundancy: Multiple backhaul options (WiFi, Ethernet, Cellular)

Data Persistence

• SD Card Logging: Store sensor readings locally
• Offline Operation: Continue logging without cloud connectivity
• Data Buffering: Upload when connection is restored
• Historical Data: Access past measurements

Industrial Features

• 24V Power: Standard industrial voltage
• Battery Backup: Uninterrupted operation during power outages
• DIN-Rail Mount: Easy installation in control cabinets
• Robust Connectors: Screw terminals for field wiring

Use Cases

Smart Metering Installations

Perfect for utility monitoring deployments:

• Mount in apartment block electrical cabinets
• Read legacy wired M-Bus meters
• Collect wireless M-Bus data simultaneously
• Log readings to SD card for redundancy
• Backhaul via Ethernet or cellular

Industrial IoT Gateway

Ideal for factory and industrial environments:

• DIN-rail mount in control panels
• Wired Ethernet for reliability
• Battery backup for critical monitoring
• Local logging for compliance

Remote Monitoring Stations

Suitable for off-grid installations:

• 24V power from solar systems
• Battery backup for night operation
• SD card for offline data collection
• Multiple connectivity options

Building Automation

Deploy in commercial buildings:

• M-Bus for HVAC and utility meters
• Ethernet backbone connectivity
• Local data aggregation
• Centralized cloud reporting

Technical Integration

S0 Connection

The Base Board provides:

• Standard pin headers matching S0 pinout
• Power delivery to S0 module
• SPI bus for Ethernet (W5500)
• UART for M-Bus transceiver (TSS721A)
• SPI for SD card
• GPIO for control signals

Communication Interfaces

Ethernet (W5500)

• SPI interface to S0
• 10/100 Mbps
• Auto-negotiation
• Hardware TCP/IP stack

M-Bus (TSS721A)

• UART interface to S0
• Master and slave modes
• Standard M-Bus timing
• Isolated communication

SD Card

• SPI interface
• SDHC support
• FAT32 filesystem
• Hot-swappable

Power Architecture

Input Stage

• 24V DC nominal input
• 18V - 36V operating range
• Screw terminal connection
• Fuse protection

Battery Stage

• JST connector for Li-Ion/LiPo
• Automatic charging
• Charge management IC
• Voltage monitoring

Output Stage

• Regulated 3.3V for S0
• Regulated 5V for peripherals
• Power sequencing
• Brownout protection

Mechanical Specifications

Dimensions

• PCB Size: TBD
• Height with S0: TBD
• DIN-rail compatible: 35mm standard

Connectors

• S0 Module: Pin headers
• Power Input: 2-pin screw terminal
• M-Bus: 2-pin screw terminal
• Battery: JST connector
• Ethernet: RJ45 jack
• SD Card: Push-push socket

Mounting

• DIN-rail clip
• Screw mounting holes
• Enclosure compatible