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- Path: sparky!uunet!spool.mu.edu!wupost!cs.utexas.edu!rutgers!cbmvax!grr
- From: grr@cbmvax.commodore.com (George Robbins)
- Newsgroups: comp.sys.amiga.hardware
- Subject: Re: How to access individual bits of a CIA
- Message-ID: <37056@cbmvax.commodore.com>
- Date: 16 Nov 92 06:26:45 GMT
- References: <Bxo42p.AGu@usenet.ucs.indiana.edu> <69502@cup.portal.com> <BxqxLu.682@usenet.ucs.indiana.edu>
- Reply-To: grr@cbmvax.commodore.com (George Robbins)
- Organization: Commodore, West Chester, PA
- Lines: 24
-
- In article <BxqxLu.682@usenet.ucs.indiana.edu> graham@venus.iucf.indiana.edu writes:
- > In article <69502@cup.portal.com>, Dan_E_Babcock@cup.portal.com writes...
- > >Why don't you buy a copy of the Hardware Reference Manual?
- >
- > I have the manual. It doesn't tell me what I need to know, and neither
- > does the RKM.
- >
- > Specifically, I want to know how to directly access DRDY* and ACK*.
-
- Well, it doesn't tell you, because you can't. 8-)
-
- Assuming you're talking about the "strobe" and "acknowledge" pins on the
- parallel port, strobe is tied to the "PC" pin on the 8520, which pulses
- each time that Port-B is accessed, while acknowledge is tied to the "Flag"
- pin, which can be enabled to cause an interrupt.
-
- So, there is not much in the way of explict control or sensing of these
- signals, the 8520 stems from the days where "simplicity" of microcontroller
- chips was valued over regularity or generality of function.
-
- --
- George Robbins - now working for, work: to be avoided at all costs...
- but no way officially representing: uucp: {uunet|pyramid|rutgers}!cbmvax!grr
- Commodore, Engineering Department domain: grr@cbmvax.commodore.com
-