22-02-2023, 01:54 AM
(This post was last modified: 22-02-2023, 01:54 AM by RedskullDC.)
Hi John,
That sounds really cool.
I'd recommend a WD1772 (or 1773) FDC, it will be the easiest to use in a 28pin DIP package, with on-board digital data separator.
Will limit you to using double density only, and make you incompatible with all the single density operating systems though.
May need to tweak the boot code in the ROM too(?).
Most of the Double Density Model 1 DOSes out there all had a single density track #0, as the DD adapters all (well mostly all) had
both the 1771 and 1791 chips on board, each of which was selected by a soft switch. Normally, the 1771 was selected on power-up or reset.
Not too difficult to create an *all* double density disk though.
Example: Newdos/80 V2 has support for either a single or double density track #0 through it's PDRIVE commands.
1771 isn't too hard to find, as there were a few alternate manufacturers apart from WD (National Semi for example: https://www.ebay.com.au/itm/224738121982).
Cheers,
Leslie
That sounds really cool.
I'd recommend a WD1772 (or 1773) FDC, it will be the easiest to use in a 28pin DIP package, with on-board digital data separator.
Will limit you to using double density only, and make you incompatible with all the single density operating systems though.
May need to tweak the boot code in the ROM too(?).
Most of the Double Density Model 1 DOSes out there all had a single density track #0, as the DD adapters all (well mostly all) had
both the 1771 and 1791 chips on board, each of which was selected by a soft switch. Normally, the 1771 was selected on power-up or reset.
Not too difficult to create an *all* double density disk though.
Example: Newdos/80 V2 has support for either a single or double density track #0 through it's PDRIVE commands.
1771 isn't too hard to find, as there were a few alternate manufacturers apart from WD (National Semi for example: https://www.ebay.com.au/itm/224738121982).
Cheers,
Leslie