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📘 S0 BaseBoard#

S0 BASEBOARD

🔧 Features#

  • Onboard W5500 Ethernet controller for wired Ethernet connectivity
  • TSS721A transceiver for M-Bus communication
  • Wired M-Bus connection via Screw Terminal (J1)
  • SD Card slot for data logging
  • Dual 2×23-pin vertical pin sockets (J5, J6) for connecting the S0 board
  • 24V maximum input via Screw Terminal (J2)
  • Battery input and onboard charging circuit via JST connector (J3)
  • SPI and UART routed through J5/J6 to communicate with the S0 board
  • Protection components: diodes, inductors, capacitors for power and signal integrity
  • Modular and expandable design with solder jumpers for configuration

🔌 Connector Overview#

Reference Type Description
J2 JST Connector 24V DC Power Input
J3 JST Connector Battery Input and Charging
J5 2×23 Pin Female Header (2.54 mm) Main S0 interface (SPI, UART)
J6 2×23 Pin Female Header (2.54 mm) Secondary interface to S0
JP2 Solder Jumper Config option for W5500
JP3 Solder Jumper Config option for W5500

⚡ Power System#

  • Primary Power Input: 24V via J2
  • Battery Backup: Via J3 with charger IC circuit
  • Protection: Diodes for reverse polarity, inductors for EMI
  • Power Output: Supplies the connected S0 board through headers

🌐 Communication Interfaces#

  • W5500 Ethernet Controller:
  • Provides wired network connectivity
  • Communicates with the S0 via SPI
  • TSS721A Transceiver:
  • M-Bus driver for utility metering
  • Communicates with the S0 via UART
  • Header Connections:
  • All SPI and UART pins routed to J5 and J6

🧠 Architecture#

The S0 BaseBoard serves as a cape that powers and extends the S0 module by offering:

  • Ethernet via W5500
  • Wired M-Bus via TSS721A
  • Power management and regulation
  • Standard pin headers for seamless plug-on support

📐 PCB Layout#

  • 4-layer board with copper on F.Cu and B.Cu
  • Board thickness: ~1.6 mm (standard FR-4)
  • Modular footprint with JST and pin headers

🧩 Applications#

  • Smart grid and smart metering infrastructure
  • Industrial IoT gateway
  • Prototyping platform for M-Bus over Ethernet
  • Expansion base for S0 compute module

🔄 Interface Map to S0#

Interface Direction Connected To
SPI S0 ↔ W5500 Network Comm
UART S0 ↔ TSS721A M-Bus Comm
Power BaseBoard → S0 5V or Battery