10 Dec
1998
10 Dec
'98
9:13 a.m.
"Sean 'Captain Napalm' Conner" <spc(a)armigeron.com> wrote:
-spc (Wants to know why IBM forgot pull up resistors
on the IRQ
controller ... )
Because they stupidly decided to make them
1) edge-triggered instead of level-sensitive
2) rising-edge-triggered instead of falling-edge-triggered
Thus, if they had pullup resistors they would tend to trigger by themselves.
Of course, this doesn't explain why they didn't have pullDOWN resistors,
or why they made those two stupid decisions in the first place.
Ugh! That's yet another reason why even though the IBM PC is technically
within the charter for this mailing list, I still refuse to consider it
a Classic.
Eric