[Coco] FPGA 63x09

[jdaggett at gate.net]

Stephan 

That has been looked into. 

There are a few issues yet to be resolved, one being my time primarily. Fortunately the busy 
season of my line work is almost over and I should get more time to devote around the 
middle of May. Of the other issues are which FPGA, which development board and which 
design to modify or start from scratch. 

In the case of which design to use: 

There are four approaches that one can take

1) Modify John Kent's 6809 IP code .

2) Modify one of two 68HC11 IP codes

3) start from scratch

4) start with Fint Wheeler's code and modify it. 

I started with approach #3 until I closely looked at the freely available code from Green 
Mountain on their version of the 68HC11. I lean to the GM HC11 modification as I am a 
hardware engineer as opposed to software engineers. My HDL coding style lends more to 
me thinking in terms of hardware rather that more abstract levels. So for some my HDL 
coding style may very well be primitive. I personally don't care as it is easier for me to 
comprehend what is going on. I do not like long( ten and fifteen page) processes or entities. 
To me it is easier to break them up into smaller sections if need be. The GM HC11 is rather 
easy for me to read and maybe off an easier route to mdoify. The HC11 archetecture is not 
all the dissimilar to the 6809 since both are offshoots of the 6800.  

In the case of which FPGA to use

1) Alterra

2) Xilinx

3) Lattice

4) others

I choose #2 simply because that is the brand I am familiar with and the tools are already 
loaded. I am flexible if there is need for another set of tools as long as they are windows 
based. 

In the case of development board:

There are several out there with many functions added. If XILINX is the choice, then a 
Spartan 3E would be the better choice. There are plenty of already boards that range in cost 
from about $150 to over $500. My choice is the Digilent Inc Nexsys2 board at $149. It has 8 
bit color and has plenty of ram and flash. XESS has a setup that runs about $300 and 
includes Networking capabilities. The onboard flash is pretty much dedicated for FPGA 
configuration. 

The ideal board would be the Nanoboard. But bundled with Altium's software at $4300 is out 
of reach for most. The Nanoboard is very flexible. Then there is the route that theC-ONE 
group took that has their own dedicated PCB. The could be even more expensive than a 
moderately priced development board. 

I hope I have not been to long winded in my reply even though I have. It probably has not 
been due to the lack of ability to do a 6309 IP for an FPGA. Instead what to do with it once 
one has been developed. 

just my thoughts 

james

On 27 Mar 2009 at 8:48, Stephen Adolph wrote:

> I notice that there is a VHDL core for a 6809.  Would we know enough
> about 6309 to be able to extend this properly?
> 
> Might be a way to a much faster 6309 capability, not sure if the
> machine could benefit from it though.
> 
> ..Steve
> 
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