Subject:
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Re: (no subject)
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Sun, 10 Nov 1996 18:43:18 GMT
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Original-From:
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Matt Harlan <mjh10@cornell=Spamless=.edu>
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Viewed:
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2608 times
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At 10:16 AM 11/10/96, Ed Arnold wrote:
> hi all,
> I have a few questions.
> 1 > Does anyone know where I can get the voltage monitor, Dallas Semi
> 1233?
I'm pretty sure JDR microdevices carries the 1233.
check http://www.jdr.com/
> 2 > Since there are 16 address lines comming from the 6811. Could I use
> a 64k Ram instead of a 32k? Is A15 being used for something else? Also
> would it be possible to use a non-volatile Dallas Ram instaed of normal
> Ram.
The HB uses A15, along with the E clock and ~reset, as the enable line for
the ram. The 64k address space gets split up so the ram is between $8000
and $FFFF. The lower 32K is used for registers in the HC11 and external
ports, like the motor latch and the digital inputs. Check out appendix B
of the 6.270 robot builders guide. It shows how the memory is divided up.
> 3 > I am considering making my own expansion board using a serial UART
> so I can have more outputs. Does anyone have any suggestions on what
> UART to use or any design ideas. I would like to keep the PCB small.
Can't help here. sorry :(
matt
_______________________
Matthew J. Harlan
Cornell University
Electrical Engineering
mjh10@cornell.edu
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