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From: lgardi@uwovax.uwo.ca
Subject: Re: Problem with Pulse Accumulator on 68HC11F1FN...
Organization: University of Western Ont, London
Date: Mon, 26 Apr 1993 14:15:52 GMT
Message-ID: <1993Apr26.101552.1@uwovax.uwo.ca>
References: <1reoniINNgi3@darkstar.UCSC.EDU>
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In article <1reoniINNgi3@darkstar.UCSC.EDU>, smythe@cats.ucsc.edu (Brian Matthew Aljian) writes:
> 
> I posted this same message to the mc68hc11 mailing list
> (mc68hc11-request@hipp.etsu.edu) but thought I might
> be able to get some help here, as well.
> 
> Hello all,
> 
> 	We're using an HC11F1FN to make a robotic mouse, and we
> 	want to use the Pulse Accumulator to give us timely
> 	interrupts to drive our motors.  We've divided the E clock
> 	down in an Altera EPM5032 and that generates a nice
> 	5V divided clock (when tested seperately).
> 
> 	Here's the problem:
> 
> 	When we hook up our Altera Pulse Accumulator signal
> 	to the PAI pin on the HC11 and check it with an oscilloscope,
> 	the Altera Pulse Accumulator signal is somehow pulled down
> 	to around 1.5V (and its fairly noisy).

Do you have a pull up resistor on this pin. I use the pulse accumulator
in a device I built to do some pretty fast counting and have had no
problem.
Good Skill.
LORI


> 
> 	Note that the PAI pin is also the OC1 and the PA7 pins.
> 
> 	We are not outputting anything to Port A.  We've tried
> 	configuring Port A as an input (default) and an output
> 	but the situation remains the same.  This shouldn't
> 	matter anyway, right?
> 
> 	Could the OC1 pin be outputting anything?  If so, why
> 	would it be outputting anything?  Aren't the OC functions
> 	disabled at startup by default?
> 
> 	Any suggestions, comments, or information would be
> 	*GREATLY* appreciated!  We're in a rush to get this
> 	thing done by next week!  :-)
> 
> 	Thanks in advance.
> 
> -Brian, Aaron, Adam, Dan
> (Please respond to smythe@cats.ucsc.edu)
> -- 
> ------------------------------------------------------------------------------
> Brian M. Aljian                                                 // Only Amiga
> smythe@cats.ucsc.edu                                           // makes it
> "Procrastinators do it tomorrow."                           \\// possible...
> ------------------------------------------------------------------------------
-- 
<<<RED FISHY WINS>>>
Lori Gardi				(519) 661-2111 ext 8695
Dept. of Astronomy,			lgardi@uwovax.uwo.ca
University of Western Ontario
London, ON, CANADA, N6A 3K7
