2 Nov
1999
2 Nov
'99
10:28 a.m.
<> So My Compupro RAM16 (64k static) in the NS* (system A) has all banks
<> enabled and if we hit e800H the FDC forces phantom/ and the ram16 is
<> deselected for that address.
<
<Ah... I see... Now, the 4FDC does not have any connection to
<pin 67, so it is not using phantom. But it should be easy to
<implement... Can I just take the /CS (-NOT- chip select) pin
<from the 2708 and wire it to 67? Maybe I need to -NOT- it first?
You could but it would be bad juju. the normal drive for phantom/
is either an open collector driver (7406, 7438) or maybe a driver
like 74126, 241, 244... to be active only when active low.
Also you don't want that phantom/ going low from some other card from
asserting CS/ on the 4fdc.
Allison