Fwd: C64 GRAPHICS CARD

From: Christopher Phillips (shrydar_at_jaruth.com)
Date: 2005-02-03 12:39:52

I think this was meant to go to the list rather than just me :)

Begin forwarded message:

> From: "Hatch" <hatch@in.com.au>
> Date: 3 February 2005 19:09:34 GMT+08:00
> To: "Christopher Phillips" <shrydar@jaruth.com>
> Subject: Re: C64 GRAPHICS CARD
>
> Fixed up that problem with the static ram.  I took a look at how 
> Nicholas
> Coplin interfaced the static ram on his Auto-RAMDOS project (Haven't 
> seen
> him post on here for a while, anyone know what he's doing?), anyway I 
> hope
> he doesn't mind me getting ideas from his design.  I was using either 
> phi 1
> or /phi 2 for /WE and Nicholas used /RW (I know this was the most 
> obvious
> way to do it but I actually didn't think the holding /WE low for the 
> entire
> write cycle would be valid).  Nicholas used /phi2 for /CS1 and I was 
> using
> RW.  So after rewiring the control signals to the RAM using the same 
> control
> lines as Nicholas had used I was ready to do another test.  It still 
> had the
> same problem (but less often, now only about every 4000 writes).  I 
> ended up
> fixing it by delaying the /CS1 signal to the RAM by sending the signal
> through a couple of NAND gates and now the cct works fine, Nicholas 
> used a
> 74HC139 in his project, maybe that delayed the /CS1 signal enough?  I 
> wonder
> if Nicholas had a similar problem when he designed his project?
>
> By the way there where only two examples I could find of a 6510 
> connected to
> static ram, one was Auto-RAMDOS and the other was the UltiMax designed 
> by
> Commodore.

John West and I built a 128k ram expansion once, but never found the 
time to work out why it completely failed to work..

>
> I guess the next step for me is to decide on what features will go 
> into the
> redesign of the video cct.

trapezoid fill ;)

(a slice of a triangle with horizontal top and bottom edges)


>
> ----- Original Message -----
> From: "Christopher Phillips" <shrydar@jaruth.com>
> To: "Hatch" <hatch@in.com.au>
> Sent: Thursday, February 03, 2005 3:38 AM
> Subject: Re: C64 GRAPHICS CARD
>
>
>>
>> On 2 Feb 2005, at 21:41, Hatch wrote:
>>
>>> I've been on holidays the last few days so I finally interfaced my
>>> graphics cct to my 64, now my C64 has a brand new graphics mode :)
>>
>> Awesome :)
>>
>>
>


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