[Coco] Learning CPU Architecture and Digital Design

[jdaggett at gate.net]

On 17 Feb 2013 at 18:09, Kip Koon wrote:

> Hi All,
> Thanks for the answers!  Whew! There certainly is a lot to consider.  As you
> might have guessed, I was thinking of John Kent's System09 and Gary Becker's
> Coco3FPGA cores.  I didn't know both of them used the same CPU09 core.  I
> stand corrected. Thank you guys.  I've been trying to look at System09 with
> Xilinx ISE and when it tries to migrate to the current version, an error
> message says "Source files in the project cannot be found (2)" and the file
> "sys09s3s.vhd" is listed twice.  The full pathname is
> "E:/Emulators/Coco/System09/System09/trunk/src/sys09bug/sys09s3s.vhd".  Any
> ideas John?
> Kip
> 


Kip 

The last time I checked about 2 yrs ago Gary used John's CPU09 core and did a Verilog 
version of the GIME chip all in a Xilinx Spartan3. Allthat work has also been ported over to 
Altera DE1 board. 

There were two commercial available cores about three years ago. I am not sure those are 
still available and/or how much they wanted for it. The 6809 is a neat processor especially for 
its time. The idea of four pointer registers was nice. The 6809 and the 6309 with its four 
pointer registers make running Forth a lot easier and quicker I think than many of the 8 bit 
processors of that era. It also makes for some interesting programing in that you can have a 
program stack and a data stack. 

I have at times thought of taking Karl Lundt's SBASIC Compiler for the HC11 and see if it 
could be ported over to the 6809. Since that basic has a stack pointer and data pointer, that 
plays very well with the S pointer register and the U pointer register. 

james