please see the embedded comments below.
Dick
-----Original Message-----
From: Tony Duell <ard_at_p850ug1.demon.co.uk>
To: Discussion re-collecting of classic computers
<classiccmp_at_u.washington.edu>
Date: Sunday, April 18, 1999 2:05 PM
Subject: Re: z80 timing... 6502 timing
>>
>> If one were going to put an FDC in place, the easiest probably would be
the
>> WD3765, since it has built in cable-drivers and receivers as well as
>
>Sure. Or one of the similar, but incompatibly pinned-out UMC disk
>controller chips.
>
>Heck, it wouldn't be hard to add one of the multi-I/O chips from a PC I/O
>card and have FDC, 2 serial ports and a printer port. Most of them only
>need an 8-bit data bus for those functions.
>
>> clock/data processing hardware. You connect it directly to the cable, as
I
>> recall. It otherwise behaves as a uPD765 (i8272).
>
>Absolutely. The point I was making (not very clearly) is that WD FDC
>chips are getting hard to find, but there's no reason not to use an 8272
>(or one of the later chips based on this, but with more things integrated
>into the device).
>
>But if you insist on 'classic' hardware (meaning all the chips you use
>were in production at least 10 years ago), you probably won't be allowed
>to use some of these more integrated devices.
That's exactly the reason I'd prefer to use the WD1002 boards I have around.
They handle both the FDC and HDC functions with a minimum of extraneous
hardware and would, at least in the case of the Z-80 lead to a productive
OS. That's not as likely in the case of the 6502, since there wasn't much
of use around for it. Nonetheless, a nonvolatile storage medium of some
sort would be convenient, and if I make the board in question home to both
processors there'll be no doubt about whether one or the other has more or
better resources. I got these boards in 1982. When they were brand new
products and, in the case of the 1002's, before they were released
commecially.
>-tony
Received on Sun Apr 18 1999 - 23:55:31 BST