[comp.unix.i386] Bus Mouse and interrupts.

pauls@inco.UUCP (Paul Stygar) (08/24/90)

There was an article a few weeks ago describing the advantages of a
bus mouse using a 16-bit bus card.  For reference,  I've attached the
article in full below.  I just recently checked this out,  and the news
is much better than the "good news" reported by Jonathan Meyer,
University of Sussex,  19 Jun 90 19:52:00 GMT.

Basically the bus card available from  Mouse Systems Corp (MSC)
47505 Seabridge Drive,  Fremont,  Ca. 94538,  (415) 656-1117
is a 16 bit bus card that supports a *** SERIAL MOUSE ***  !!!!

You can buy an MSC mouse and hook it up to the MSC bus card and use
IRQ 10 and free up one of those precious IRQ 3 thru 8.  But you can hook
up your current serial mouse instead !!   Here's the blow-out news:
The MSC bus card comes in an "extended" version which supports 2
additional port addresses and 5 additional IRQ,  you can choose any
IRQ between 9 and 15.   The extended bus card is avail only from MSC
direct,  but the price is very reasonable.   You buy the extended bus
card,  hook up your current serial mouse,  and happiness is a free IRQ !

The bad news is that MicroSoft Windows 3.0 mouse driver doesn't support
the IRQ 9 thru 15.  This is good news for the I386 UNIX folks,  since
it's created a huge lack of demand for the MSC bus cards.  They're
just sitting on shelves in warehouses.  The discount mail order houses
are discounting them heavily.

The technical info above was obtained from MSC technical dept (John Vineyard),
I hope I haven't mangled it too badly.  I have no connection with MSC except
as a satisfied customer.  Below is John's original article:

In  <2921@syma.sussex.ac.uk> 19 Jun 90 19:52:00 GMT jonm@syma.sussex.ac.uk (Jonathan Meyer, University of Sussex)  wrote:
> baxter@zola.ICS.UCI.EDU (Ira Baxter) writes:
> 
> > The [MS BUS] mouse only offered interrupt levels 2-5
> 
> I just got a Mouse System optical bus mouse for the PC/AT bus (about $80 from
> softsel, called PC Mouse Bus Plus or something), and was VERY pleased to note
> that it came with a card that can be plugged into a sixteen bit slot and set
> to generate interrupts 8-16 rather than just 1-8. This isn't mentioned
> anywhere in the advertising or on the packaging, but considering the extreme
> shortage of 8 bit interrupt vectors, and the larger number of 16-bit slots on
> most 386's, I see this as being a huge advantage!
> 
> It also comes with a (DOS) program for helping you to choose the correct
> interrupt level/address. Considerate when I think how little I know
> about the interrupt levels > 8.
> 
> On the down side, the installation scripts for Interactive 2.0.2 don't tell
> you how to set up the MSC-Bus mouse correctly. For anyone out there who wants
> to know, the MSC Bus mouse interface appears to the system as a standard
> serial port, so you need to modify the kernel config file for the asy driver
> (/etc/conf/sdevice.d/asy) so that it looks something like (I use interrupt 10,
> IRQ 338):
> 
> asy     Y       1       7       1       4     3f8     3ff     0     0 #com1
> asy     Y       1       7       1       3     2f8     2ff     0     0 #com2
> asy     Y       1       7       1       10    338     33f     0     0 #mouse
> 
> Rebuild the kernel, setup the Xconfig file to include the line:
> 
> mouse           MSC-B   "3"             0       /dev/tty02
> 
> Perhaps run mknod (I did, but this may well get done for you) eg:
> 	# mknod /dev/tty02 c 3 2
> 
> and your off!
> 
> Happy mousing.
> 
> Jon.
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