re PLP_A Pull up not working as it should
OzStamp
Posts: 377
Has anybody experienced an issue with the PLP_A not working properly.
I have 4 inputs we want to read in on Port A and have used PLP_A = %0000
Now when checking it with a HI-Z Fluke Multimeter it tells me the pins float...
and my code does really strange things ( obviously seeing floating pins ..hi and lo's ....)
As soon as I connect resistors to the pins as pull ups ( some 4.7K even 10K type)
my code behaves as it should...
Cheers
·
I have 4 inputs we want to read in on Port A and have used PLP_A = %0000
Now when checking it with a HI-Z Fluke Multimeter it tells me the pins float...
and my code does really strange things ( obviously seeing floating pins ..hi and lo's ....)
As soon as I connect resistors to the pins as pull ups ( some 4.7K even 10K type)
my code behaves as it should...
Cheers
·
Comments
Bean.
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If what you wrote is literally as your code reads, then you are might be missing the "#" literal prefix in the pull up definition.
But in any case, I fully agree with Bean; without being able to see it, we can only guess what your code is doing, and that's not a good use of our time.
Cheers,
Peter (pjv)
I have attached my code for your perusal.Tried to add the # it is not valid code the compiler rejects it
As mentioned before my program behaves as it should but the Pull up resistor command does not work
I have external Pull UPS at the moment and I like to get rid of them.
Cheers
Ronald Nollet Australia
The pull-ups work fine with nothing connected to the RA pins. What do you have connected to them ?
The pull-ups are very weak (approx 20K) so any circuit connected to them might bring the level down.
BTW: You know you can just use "adder = 15 - RA" instead of all them IF statements...
Bean.
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Cheap 4-digit LED display with driver IC·www.hc4led.com
Low power SD Data Logger www.sddatalogger.com
"You're braver than you believe, stronger than you seem, and smarter than you think" Christopher Robin to Pooh
Post Edited (Bean (Hitt Consulting)) : 8/15/2006 11:23:45 PM GMT
I converted a BS2E program from a customer quickly so code looks accordingly.
(All done free of charge basically to get a sale)
Thanks for the pointer re code I tried something similar but had problems ..( as we are talking about)
So just adjusted the customers code to suit ..
(Omron A6C type 6 pinner device dip top adjust BCD output)
A little BCD dipswitch as above is connected to the pins A0...A3 pulling these pins low.
Or nothing at all just connecting very short jumper wire to the VSS IDC female socket to the right of them..
So no other stuff at all.
Using the SX Tech board to Proto-type it ( with the SXKEY F)
The application is very price sensitive and the PCB needs to be small
Parallax OZ disty
Ronald Nollet
If you pull the BCD switch out of the circuit, then do the pins go high ?
Bean.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Cheap 4-digit LED display with driver IC·www.hc4led.com
Low power SD Data Logger www.sddatalogger.com
"You're braver than you believe, stronger than you seem, and smarter than you think" Christopher Robin to Pooh
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With nothing connected to the pins and all pulled up on a anti static mat grounded using the Debug mode
now I can pins toggling all by themselves on port RA and also RC .
Tried another chip same thing exactly the same ...
As soon as I put my pull up resistors back in all runs as it should.
In debug mode there seems to be a pattern as to when it happens.
As to exactly when I have no idea but when it sits in the "final do nothing loop" the pins all read 1
So this is as it should be.
Cheers