Subject:
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important update to Handy Board standard libraries.
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Wed, 20 May 1998 00:18:12 GMT
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Original-From:
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Fred G. Martin <FREDM@stopspammersMEDIA.MIT.EDU>
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Viewed:
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1205 times
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Hi all,
There has been a bug lurking in the Handy Board standard library files
since the dawn of time (well, 1996, when the HB got started).
The bug can happen when you are using multi-tasking, and more than one
IC task is performing analog sensor readings, or if you have loaded
drivers that may perform analog conversions (e.g., the shaft encoder
utilities).
In the subroutine in lib_hb.c which performs analog readings
(_raw_analog), it is possible for another process (either an IC
process or an assembly language driver) to interrupt the analog
conversion, in between the time when the analog channel is selected
and the result is read back. If the interrupting process performs an
analog conversion of its own, when the interrupted subroutine gets
control back, it reports the later reading rather than the one it
started.
I've posted an updated version of the libraries that fix this problem.
A short assembly language driver performs the basic analog read
function. Interrupts are disabled during the span between the
selecting the analog channel and reading the result.
I recommend that everyone download and install these new drivers.
Aside from fixing this intermittent bug, the new driver is faster and
smaller.
To download, please see the Handy Board home page:
http://el.www.media.mit.edu/projects/handy-board/
Let me know if you have any questions or concerns.
Fred
P.S. Thanks to Ericson Mar and Rick Freuler for noticing and
reporting this problem.
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Message has 3 Replies:
 | | Question about Sharp IR demodulators
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| Hi everyone, First, sorry for the blank message just now -- hit the send button instead of the cancel. I'm working on a project where I've got robots hunting targets equipped with a 40 kHz oscillator circuit which is continuously pulsing an IR LED. (...) (26 years ago, 10-Jun-98, to lugnet.robotics.handyboard)
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