Re: C64 MMU POC

From: Jim Brain <brain_at_jbrain.com>
Date: Wed, 9 Oct 2019 19:00:32 -0500
Message-ID: <b5a5d583-3faa-ff4b-7b8d-8dc6a81d49a4_at_jbrain.com>
On 10/9/2019 4:29 PM, Istvan Hegedus wrote:
> Hi,
>
>     I assume you refer to VIC-II (and in general the 4k I/O block on a
>     C64). I haven't done any testing myself but I would be really
>     surprised
>     if writes bleed through.
>
>
> I have done measurements on TED and in the I/O block area CAS is not 
> activated thus the write does not bleed through to ram.
> Most probably VIC-II behaves the same
>
> Istvan

Which is why I am hesitant to put it in the VIC-II (yes, not VIC-20) 
address space.  It has to be something that will get written as RAM in 
the address space.

But, I like the earlier idea of using the "unlock" sequence to signify 
where to show the registers.  So, I will see if I can work that in.

Jim


-- 
Jim Brain
brain_at_jbrain.com
www.jbrain.com
Received on 2020-05-29 23:03:21

Archive generated by hypermail 2.3.0.