Messages in this thread | | | Date | Tue, 14 Sep 1999 09:41:01 +0200 | From | "J.D. Bakker" <> | Subject | Re: Designing a keyboard controller |
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[designing a keyboard controller to work with Linux]
>Whatever hardware you need, the best is really to use something that can >be atached to the so called pcmcia bus on the SA1100. You might need some >logic to decode the address and activate a chip-enable signal if you have >more than one port to address. A GPIO, preferably between 0 and 10, can >be used as interrupt line. > >With such a setup around the SA1100, current ISA drivers can be used with >very minimal modifications as long as they aren't using DMA. The kernel >code for the SA1100 already provides access to that bus through the >in*()/out*() macros. You then have plenty of choice for an interface >chip.
That looks like a good solution. The question remains then: what does an 8042 'look like', as seen from Linux ? I want to mimic the ISA side of a regular keyboard controller (without actually cramming a 40pin DIL chip on my 7.5x10cm PCB :-P). Does anyone have pointers to documents on this ?
A semi-related question: is it possible for multiple different devices on an ISA-ish bus to share an interrupt *on the processor side* ? For example, say I have a custom PIC which multiplexes (logic OR) the interrupt output of a keyboard controller with the interrupt output of an IDE controller onto one interrupt line for the processor. Does this work, or do I break any hidden assumptions in either the keyboard or the IDE driver ?
Sincerely,
JDB.
-- Jan-Derk Bakker, bakker@mmc.et.tudelft.nl
The lazy man's proverb: 'There's no business like slow business !'
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