Re: 6809 on C64 Development

From: Jim Brain <brain_at_jbrain.com>
Date: Tue, 10 Jul 2018 12:43:51 -0500
Message-ID: <01e39cb6-f558-a107-7097-9c87e916603a@jbrain.com>
On 7/10/2018 1:01 AM, Baltissen, GJPAA (Ruud) wrote:
>
> Hallo Jim,
>
> How is the development of the card going?
>
Phase I of development/design is done.
Phase 2 requires I focus on REU functionality
Phase 3 will allow the card an option to operate in parallel with the 
6510 or operate as a replacement CPU for the 6510.

Right now, I am learning the specifics of REU functionality (basically, 
being able to coordinate with VIC-II for the local bus to share memory.

Specifically, one way or another I am going to implement a CPU 
accelerator for hte 64.  Mostly to prove to myself I can do it. Right 
now, the big hurdle is sharing the 64 bus.  I decided to implement REU 
functionality because it's a good place to learn, and I figured the 
outcome might be a working REU Verilog core.  Writing data from 64 to 
external RAM is working fine, with the expected REU registers and such, 
but reading is not (for some reason, all 64 RAM locations get the value 
of the first external RAM location, and I can tell I am incrementing the 
counters).  Once I can overcome that, then I can move to Phase 3a, which 
is running the 6808 as main CPU on 64 at 1MHz, and then Phase 3b would 
be to accelerate it and add in the code to halt the CPU if a memory 
value needs to be stored in main RAM.



> The reason why I ask is that I finished the 6809 part of my assembler 
> yesterday. So if you need a tester, I could be of help.
>
I can share now, as an IPC mechanism (for parallel 6809 execution) is 
needed for operation.  Are you aware of FLEX or OS/9 OS?

Jim
Received on 2018-07-10 20:00:04

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