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Subject: 
Help! - Strange Bug.
Newsgroups: 
lugnet.robotics.handyboard
Date: 
Wed, 5 Mar 1997 18:47:40 GMT
Original-From: 
Moxey C E <cemoxe%essex.ac.uk@seralph21.SPAMLESSessex.ac.uk>
Viewed: 
2395 times
  
Hi All,
I have recently completed construction of a Handyboard which passed all
it's initial tests with the downloader, pcode and hbtest.c program,
thanks to some help from Fred Martin, and I am now enjoying writting
some programs for it. However I have now discovered that I can not read
the START switch anymore. The start_button() and start_press() library
functions from lib_hb.c are both dead. I firstly checked the switch
itself as the software appeared to suggest that the switch was welded
closed, but there is nothing wrong with it. Switches from 5V to gnd and
back - no problem. Then I checked the wiring the start switch to its
1K ohm pull-up resistor and then to the 74HC244 on pin 17. All ok! I
then doubled checked the data lines, especially D7, back to the micro,
not that there is anything wrong with any thing else in the system which
would be the case if a data line had gone down. But everything checks
out. By the way the STOP switch and all its functions work correctly.
If anyone has experienced a similar problem or can think of anything
that I might have forgotten I would appreciate your comments. Thanks,

Eddie
cemoxe@essex.ac.uk



Message has 1 Reply:
  Re: Help! - Strange Bug.
 
(...) Do you recall ever feeling a static electricity shock when you went to press the start button in the past? The bug has all of the earmarks of a static damaged part. If other programs still work then it is probably U5 (the 74HC244) try (...) (28 years ago, 5-Mar-97, to lugnet.robotics.handyboard)

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