System09, a 6809-based complete system-on-FPGA, does defeat 6809 Obsolescence !

What is System09 ?

Based on the excellent work of John Kent, in Australia, we have built in 2007 a fully synchronous (rising_edge) and cleaned up version of his 6809 processor.

We have also updated his System09 platform, which is now target-independent and verified by test benches and behavioral models, and has been tested on several Altera boards.

We have used this port in an industrial design.

The 6809 CPU fits in 2200 Logic Elements. As a consequence, a complete CPU board with many (obsolete) peripherals and even some memory can fit in a single and small FPGA.
This has applications beyond the nostalgic hobbyists !

How can I try it ?

You can download the bitstream of this System that runs on the old and cheap Terasic DE1 kit (Cyclone II) and you can test it very easily :

  • Program the DE1 with the DE1_System09_bitstream (.sof file).
  • Plug a PS/2 keyboard (QWERTY !)
  • Connect a screen to the VGA connector
  • Optionally : connect an RS232 cable on the serial port with a PC as terminal. Configure the terminal program (PuTTY or Hyperterminal eg) for 57600 bauds, N81, and no handshake.

That’s it ! LEDr9 should “beat”, indicating that our design is loaded, and you should see the message “K_BUGS9S V1.0” followed by a prompt on the screen.

  • You can now enter 6809 Monitor commands using the Keyboard.
    Note that the LEDs (LEDr0..8) monitor a part of the CPU address bus.
  • Try entering the following command (UPPERcase, spaces optional):
    E FE00 FFFF.

The serial (RS232) port is operational and you can debug and load compiled code using a PC as a terminal (with the “L” command).
With the serial port, you don’t even need the keyboard nor the VGA display.

Interested ?

If you need to convert an obsolete system that used a 6809 FPGA, ALSE can do this for you ! We will analyze your board, and see what other components beyond the CPU we can convert into an FPGA. Most of the time, we can convert the external SRams, the old E2Prom memories, some CPU peripherals (UART, Timers, PIOs etc).

Please contact us if you want to evaluate the opportunity to redesign an obsolete board.

You can also read our small article about Obsolescence.