From: Jack Rubin (jack.rubin_at_ameritech.net)
Date: 2007-12-11 22:08:26
Moving just mildly OT, what would it take to interface this to a CBM/PET
system?
Jack
> -----Original Message-----
> From: owner-cbm-hackers@ling.gu.se
> [mailto:owner-cbm-hackers@ling.gu.se] On Behalf Of Jim Brain
> Sent: Tuesday, December 11, 2007 2:57 PM
> To: cbm-hackers@ling.gu.se
> Subject: Re: (Fwd) RE: 1541IDE and 1541IDE-S
>
>
> silverdr@inet.com.pl wrote:
> >
> > On 2007-12-10, at 23:54, Jim Brain wrote:
> >
> >> Ruud sent me his schematics, and I am fiddling with them.
> >>
> >> However, I didn't get any emails on my offer to design and buy some
> >> etched boards.
> >> Just thought I'd check.
> >
> > I could do it myself but if you're going to have some
> available - I'll
> > buy from you.
> >
> >> If no one is interested, I thought I might see if I could extend
> >> the design to do 16 bit transfers without too many more ICs.
> >
> > Sure! That's a very natural (and good) extension of Ruud's idea.
> >
> I believe I have a design that retains source compatibility
> with Ruud's
> project, but it'd be nice if others could look the logic over
> and verify
> it, since I don't do 6502 interfacing projects a lot.
>
> The changes I made were:
>
> * I mapped the IDE to A4,A3,A2,A1 (instead of Ruud's A3,A2,A1,A0)
> leaving A0 as the hi/lo byte select
> * I added another '139, half of which is used to further constrain
> the onboard CS line so that the IDE lines are only
> active when A0
> is low.
> * I added 2 '573s, in both directions, used as a staging area for
> the hi byte of the IDE databus
> * The other half of the '139 is used to select one of 4 operations
> for the '573s:
> o During Read and A0 is low, we are reading from
> IDE, so store
> hi byte in 573
> o During Write and A0 is low, we are sending to
> IDE, so output
> hi byte on IDE bus
> o During Read and A0 high, we are reading from 573,
> so output
> 573 on 6502 bus
> o During Write and A0 high, we are writing to 573, so store
> data into 573
> * I used a 74LS02 to constrain CLK lines into the 573s with Phi2.
> * Due to this design, order of access is very important.
> Reads must
> always start with low byte, writes must always start
> with hi byte.
> * Finished board fits on 2.6" by 3.6". and 9 will fit on
> an 8x11 panel.
> * If additional '139, '02, and '573s are not populated, circuit
> approximates Ruud's original (addresses being shifted)
>
> Total circuit takes 7 ICs (244,245,139,139,573,573,02), an IDE
> connector, and a half dozen passives.
>
> As always, comments and help appreciated. If people can
> either verify
> my design would work, (or verify that it won't, so I'll need to use
> Ruud's original design), I can probably spin the boards this week.
> Christmas presents for folks.
>
> Jim
>
>
> Message was sent through the cbm-hackers mailing list
>
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.503 / Virus Database: 269.17.0/1180 - Release
> Date: 12/10/2007 2:51 PM
>
>
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.503 / Virus Database: 269.17.0/1180 - Release Date:
12/10/2007 2:51 PM
Message was sent through the cbm-hackers mailing list
Archive generated by hypermail pre-2.1.8.