Re: How does ]['s video work?

[shoppa@altair.krl.caltech.edu (Tim Shoppa)]

In article <44kfn4$65d@terpsichore.src.honeywell.com>,
Dave Lowry <lowry@src.honeywell.com> wrote:
>Could someone give me a pointer to a reference on how the Apple ]['s video
>works?  Specifically, how does the logic develop the sync, blank, etc.
>signals.  I'm familiar with CRT controllers like the 6845, but can't
>figure out how the Apple did this with just a few chips.  Thanks.
>
>-Dave
>lowry@src.honeywell.com
>
Depends, of course, on which Apple ][ you're talking about.  The ][ and
][+ have a rather ingenious concoction of MSI and SSI TTL wired together
to do the job.  The //e, //c, and GS have custom LSI chips doing
the work.  Which implementation are you interested in?  

If you were referring to the ][ or ][+, I'm sure Woz would be gratified
to hear your comment about "just a few chips".  Woz is quite proud of
his ability to shrink one-hundred-chip designs to just a few!  I'll
find a reference in BYTE ('77 or '78, I believe) where he discusses
his design in a followup, as soon as I find it...

Tim. (shoppa@altair.krl.caltech.edu)