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Board Bring-Up: Hardware

This document covers the steps needed to source, assemble, and set up the required hardware for connecting FujiNet to a new or unsupported platform. Since FujiNet is based on the ESP32, most hardware bring-up revolves around the ESP32 DevKit-C and attaching it to the target serial or parallel interface.

For the software side of board bring-up, see the Board Bring-Up Software documentation. For questions and community support, visit the FujiNet Discord.

Terminology

TermDefinition
PlatformA specific set of hardware from a manufacturer with common I/O characteristics (e.g., Atari 8-bit with SIO, Apple II with SmartPort, ADAM with ADAMnet, Commodore 64 with IEC)
FujiNetA hardware peripheral using the ESP32 and various I/O connectors to attach to different platforms
ESP32The system-on-chip (SoC) that runs the firmware and connects platforms to the Internet
BOBBreak-Out Box – an add-on device that connects to an Atari FujiNet v1.0 and provides pins for connecting to other devices
PlatformIOThe development environment used to program the ESP32 firmware, available as CLI tools or as a Visual Studio Code extension

The ESP32

The ESP32 is the heart of the FujiNet ecosystem. See the ESP32 Platform Details page for in-depth specifications. FujiNet always uses the WROVER variant, which has more RAM and Flash than the WROOM version. Using a WROOM module will cause issues due to insufficient memory.

graph TD
    A[ESP32-WROVER Module] --> B[WiFi / Bluetooth]
    A --> C[GPIO Pins]
    A --> D[SPI - SD Card]
    A --> E[UART - USB Bridge]
    C --> F[Platform Bus Interface]
    F --> G[Atari SIO]
    F --> H[Apple SmartPort]
    F --> I[ADAM ADAMnet]
    F --> J[Commodore IEC]
    F --> K[Other Platforms]

Platforms with Retail Hardware

These platforms have fully assembled, plug-and-play retail FujiNet devices available for purchase.

Atari 8-Bit

Fully supported with tested hardware, a CONFIG app for the Atari, and a web interface for all FujiNet functions.

See Official Hardware Versions for the full Atari hardware revision history.

Coleco ADAM

Fully supported with tested hardware, a CONFIG app for the ADAM, and a web interface for most FujiNet functions.

Apple II

Fully supported with tested hardware, a CONFIG app for the Apple II, and a web interface for most FujiNet functions.

Commodore 64

The Apple II prototype board can boot a C64 with the addition of an IEC cable connected to the proto board pins. A special MeatLoaf build of FujiNet firmware is required. Visit the FujiNet Discord for assistance with this configuration.

Building a DevKit

For platforms that do not yet have a dedicated retail FujiNet device, a development kit is required. The DevKit is built around the ESP32-DevKitC board on a solderless breadboard.

Required Purchases

ComponentSource
ESP32-DevKitC (WROVER)Mouser
ComponentPurpose
Breadboard jumpersShort connections on the breadboard
Dupont wiresConnections between the DevKit and target platform
Solderless breadboardsBase for mounting the DevKit and wiring

Using a FujiNet v1.0 as a DevKit

The original FujiNet v1.0 board (and only the v1.0 board) can serve as a DevKit with the addition of a Break-Out Box (BOB), available from the FujiNet Online Store. The BOB provides the same GPIO access as a breadboard-based DevKit.

Platform-Specific Wiring

Apple II

The Apple II port uses the SmartPort protocol. The target Apple II must have a SmartPort DB19 interface:

  • Apple IIc, IIc+, IIGS – SmartPort built in
  • Apple II+, IIe – Requires SmartPort ROMs in a Disk II controller, or a BMOW Yellowstone SmartPort card

Required Hardware

ComponentSource
BMOW Yellowstone (II+/IIe only)Big Mess o’ Wires
DB-19 Male Adapter (IIc/IIc+/GS)FujiNet Online
IDC20 cablesStandard IDC20 ribbon cables

GPIO Wiring

Wire the ribbon header from the DB19 adapter to the GPIO pins on the ESP32-DevKitC. The SmartPort signals map to specific GPIO pins as defined in the firmware source code, which also documents the correspondence between Apple SmartPort signals and Atari SIO signals.

Commodore 64

The C64 uses the IEC bus protocol. An IEC connector from Moz connects directly to the pin-outs on the Apple FujiNet Rev 0 and 00 boards. See the demonstration video for a working example.

Other Platforms

Additional platforms are awaiting community contributions. If you are interested in bringing FujiNet to a new platform, join the FujiNet Discord to coordinate with the development team.

Logic Analyzers

A logic analyzer is the best tool for diagnosing communication between FujiNet and a target platform. Many FujiNet developers use inexpensive USB logic analyzers based on the Saleae clone design.

The HiLetgo USB Logic Analyzer (24MHz, 8 channels) is available for approximately $13:

These are Saleae clones and are compatible with multiple software packages.

Software

SoftwareDescriptionLink
PulseViewOpen source logic analyzer GUI (sigrok project)sigrok.org
Saleae LogicOfficial Saleae software (also works with clones)saleae.com

Channel Mapping for Apple II

For FujiNet Apple Rev 0 and 00 boards, use the following logic analyzer channel mapping:

ChannelSignal
CH0RDDATA
CH1WREQ
CH2WPROT
CH3PHI 0
CH4PHI 1
CH5PHI 2
CH6PHI 3

Other platforms will have their own standard channel mappings. Consult the platform-specific documentation or the FujiNet Discord for guidance.

Testing Connectivity

After assembling your DevKit and wiring it to the target platform:

  1. Power up the ESP32 via USB and verify the serial console is accessible
  2. Flash the firmware using PlatformIO with the correct platform target selected
  3. Check WiFi – the FujiNet should broadcast an access point for initial configuration
  4. Monitor the serial console for bus activity when the target platform is powered on
  5. Use a logic analyzer to verify signal integrity and timing on the bus interface
  6. Test with the web UI – connect to the FujiNet’s IP address to access the configuration interface