From: adam@microware.com (Adam Goldberg) Subject: Re: keyboard problems - v.99 Date: 18 Dec 1992 15:03:06 GMT
erc@unislc.uucp (Ed Carp) writes:
>Dean Troyer (troyer@saifr00.cfsat.honeywell.com) wrote:
>: Port 61 is listed in my BIOS reference as being the PS/2 System Port B, although
>: it's not unique to PS/2s. It's uses include the speaker hardware & timer
>: control bits. Check out the Mach sources kd.h. The bummer is that I can't
>: find the purpose of bit 7 documented anywhere! I suspect it controls one
>: of the keyboard controller's input pins.
>Bit 7: input - 1=IRQ 0 reset (timer 0 output latch)
> output- Parity check state (1=parity check occurred)
>This is from "The Programmer's PC Sourcebook" by Thom Hogan. An absolute
>*must* if you're going to be mucking about with the hardware. :)
I hate to be contrary, but "The Programmer's PC Sourcebook" is good if
and only if you need to look up something simple. For example, if you
wanted to directly read from the keyboard controller:
You'd look to page 7-22 & 7-23 (TPPS, 2nd ed). There it says in
section 7.018 "Command value 0x20 - read keyboard controller".
What the h*ll does that mean? How do you use it? What does the
returned value mean?
There are many better books. For example, "IBM Microcomputers: A
programmer's handbook" by Sanchez.
Though I guess I can't fault Hogan too much. The PC architecture is a
friggin mess, with very little standard anything. Everybody does
everything just a tiny bit different. Just enough to screw things up.
Adam
-- Adam G. adamg@microware.com, or ...!uunet!mcrware!adamg The above is not to be construed in any way as the official or unofficial statements of Microware, or any Microware employees.