Cyboard is a Symbiface II clone with embedded Ethernet controller for the Amstrad CPC range of computers.
Its Ethernet controller is supported by SymbOS (download the network daemon here) and by KCNet utilities for CP/M.
- Compact Flash Card mass storage device
- PS/2 compatible USB Mouse controller
- Real Time Clock
- Ethernet controller with embedded TCP/IP stack
- Reset button
Unlike Symbiface II, Cyboard doesn't integrate RAM or ROM expansion for the CPC.
All the integrated devices are fully compatible with the original Symbiface II thus using the same I/O port addresses.
The interface uses a full 16-bit address decoding. A dual 4-input AND gate 74HCT21 and a GAL20V8 PLD is used for this purpose. All the GAL's outputs are programmed as combinational outputs.
The interface has a Mother X4 compatible connector.
The CF card works in memory mode so it can be directly addressed as an 8-bit device and has no need for initialization via software.
The mouse controller is a Microchip PIC16F84A programmed in assembly and it is clocked by the CPCs 4MHz clock. It supports mice with 5 buttons and scroll wheel.
The RTC module is the famous DS12887 which is also used in the original Symbiface II.(variants DS12887A, DS12C887, DS12C887A can also be used)
The network module is based on the WIZnet's W5100S embedded ethernet controller and works in indirect parallel bus mode.
In this mode it needs 4 I/O ports:
- #FD20: MR - Common Register MR
- #FD21: IDM_ARH - Upper 8 bits Offset Address Register
- #FD22: IDM_ARL - Lower 8 bits Offset Address Register
- #FD23: IDM_DR - 8 Bits Data Register
A detailed description on how to program the module, with flow diagrams and programming examples, can be found at the WIZnet's official site:
W5100S TCP Function
W5100S UDP Function
SOCKET-less Command
The module that's been used in this implementation is one with an integrated 3.3V regulator but also the original WIZnet's W5100S and W6100 modules can be used instead, with small changes in the design.
The schematic and layout were generated with Autodesk EAGLE 9.6.2 free edition
The GAL20V8B files were generated with Atmel WinCupl 5.30.4
The PIC16F84A files were generated with Microchip MPLAB IDE 8.83