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Date:      Sun, 5 Oct 1997 11:25:58 -0700 (PDT)
From:      mdean <mdean@best.com>
To:        Mike Smith <mike@smith.net.au>
Cc:        freebsd-hackers@FreeBSD.ORG
Subject:   Re: A world of unexplored pain. 
Message-ID:  <Pine.SGI.3.95.971005111430.2752A-100000@shellx.best.com>
In-Reply-To: <199710050846.SAA00411@word.smith.net.au>

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The fastest I can run a KA series is at Crystal Freq = 16Mhz, EClk = 4Mhz,
so if you look on page 10-12 of the hc11 reference manual you see that a
divisor of rtr1=0 and rtr0=0 does E/2^13 netting a 2.05ms period between
interrupts (this is only half of what I need) 

Ever seen a stepper motor controller that can be retargeted as it moves?

> Uh, excuse me.  A 1kHz interrupt gives you 2000 machine cycles between 

> You should re-read the HC11 reference, particularly the section where 
> they discuss interrupt priority.

Yes, you can make any single interrupt the highest priority.

Thats just it, I wouldn't be using an interrupt it have to be a tight loop
running in the busy wait state monitoring the system clock reg that
increments with every.

>From what I've seen, not gates with outputs that go to a shared bus have a
single input and a tristate enable? input, if the enable is off the output
becomes a very high impedance input. Makes it so that the output has no
effect on that line.  Now I'm not really sure about wired-or, but I get the
idea that it allows you to hook a whole bunch of stuff to the same
interrupt line without using or gates, if any one output goes high the
others don't interfere.





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