[Coco] Learning CPU Architecture and Digital Design

[Kip Koon]

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

-----Original Message-----
From: coco-bounces at maltedmedia.com [mailto:coco-bounces at maltedmedia.com] On
Behalf Of Mark McDougall
Sent: Sunday, February 17, 2013 6:36 AM
To: CoCoList for Color Computer Enthusiasts
Subject: Re: [Coco] Learning CPU Architecture and Digital Design

On 17/02/2013 8:30 PM, Kip Koon wrote:

> because there are two versions of the 6x09 processor core in existence 
> ready to burn into an FPGA chip.

I only know of one version, John Kent's CPU09, which is the core that Gary
Becker is using in his Coco3FPGA project.

If you say there's another one, I'd be *very* interested, but I suspect
you're mistaken!?! Hoping not though! :)

> I'd like to expand the
> 6x09 core (not sure which one to pick yet) into a core with a 24-bit 
> address bus and keep the same 8-bit data bus while at the same time 
> preserving the complete instruction set, if possible.  Has anyone else
ever had this idea?

IIRC John himself was looking at enhancing his CPU09 core, though I can't
recall the exact details of what he was planning. I'm guessing you're
looking at some sort of 'segment' (for lack of a better word) register(s)?!?

> I'd also like to study this subject in detail.  In order to facilitate 
> my studies, which book(s) would you all suggest I look into getting?  
> Thank you all for your help.

There was a book on CPU design in VHDL but I can't recall the title (never
used it). A quick google search brought up a PDF from opencores on the
subject, for example.

I think if you have some sort of grounding in CPU architecture you best bet
would be to dive in and study the CPU09 core itself. I've personally studied
a few of the cores (6502 & Z80 primarily) and briefly perused John CPU09
core (to track down an issue) and it's not that difficult to grasp how they
work if you spend enough time with them. Of course, you still need a
grounding in CPU architecture first.

Regards,

-- 
|              Mark McDougall                | "Electrical Engineers do it
|  <http://members.iinet.net.au/~msmcdoug>   |   with less resistance!"

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