The Godils are no longer made so a new FPGA board was needed to continue the project.
The XC6SLX9 Mini Board can be obtained from the ebay vendor eepizza for ~£25.
Overview of the XC6SLX9 Mini Board
XC6SLX9 Mini Board is an easy-to-use FPGA platform based on Xilinx Spartan 6 series FPGA. It was initially designed for low cost with a everyone affordable price. Up to 72 I/O breakout makes it suitable in high pin count applications. You can connect the I/Os to your peripheral module with several flying wires to quickly build a prototype project. Also, one USB to UART bridge is integrated on board, only a USB cable is needed for power supply and data communication. Because of its compact size and abundant I/Os, it can be easily embedded in your design as a core.
Features :
- Based on Xilinx Spartan 6 FPGA-XC6SLX9 (9,152 logic cells).
- On-board USB to UART converter (Genuine FTDI FT232RL) with LED indicator for RXD and TXD activity
- On-board 50M Hz oscillator
- +3.3V LDO for IO supply
- Eight LEDs for general LED experiments
- Two tact switches
- Two groups of 40-Pin header,with +5V,+3.3V and 72 GPIOs breakout
- 14-pin 2.54 pitch JTAG configuration interface
- Non-volatile configuration device : W25Q32BV
- One reset button for device reconfiguration
- +5V Power could be sourced from USB or external supply
- PCB Size : 50mm*75mm
Passive Level Shifter (obsolete)
The first application of this board was with a passive (FET based) level shifter designed by Jason Flynn. There are some photo here.
Jason did a limited run of these board, and they are no longer available.
They also used the same type of level shifter as the GODIL, which uses strong (1.5K) pullups which cause compatibility issues in many system.
Active Level Shifters (new in October 2019)
To improve system compatibility, a new family of CPU adapters using active level shifers is being designed.
There are currently three varients of this:
- a 6502/65C02 CPU adapter
- a Z80 CPU adapter
- a 6809E CPU adapter
You can see some pictures of the 6502 adapter here.
You can see some pictures of the Z80 adapter here.
The 6809E adapter is still in development.
As of writing in October 2019, these are currently being tested by a few people, but already the results look good.
An update on the testing of the Z80 can be found here.
An update on the testing of the 6502 can be found here.
The new design uses a multiboot firmware image that reads the ID links on the adapter board and boots to the appropriate processor. So all that's needed to reconfigure from one CPU to another is to switch over the adapter board.
For more information on these board, contact hoglet via the stardot forums.
GODIL Hardware (now obsolete)
XC6SLX9 Mini Board (eepizza)
Tutorials:
User Manual
Hardware design notes
Software design notes