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Old 2nd Aug 2021, 9:05 pm   #67
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 7,539
Default Re: MK14 Programming Interface

As a first step, do you know the 'key14' test utility which comes with the uploader 'software' package - if you run that up and use the Pi's keyboard (actual or remote, via SSH) to 'press' MK14 keys, do they ever bounce in the same way as your keys do when you are using the physical keys?

Connect any other momentary contact switch across the 'Mem' row and column on the edge connector and use that to step through the memory locations - does it bounce - skip locations sometimes - if you do that?

Does the extent to which this happens change when the interface is / is not connected? I have only ever used the TLP185 optos in my own interfaces so I can't say whether your PC817s will completely let go of the keypad lines when turned off. However, I think you originally had this problem before you even built the uploader.

As far as I know I'm using the exact same hardware in my issue VI -except- that I am using Omron branded low Newton force tact switches which were bought through Farnell. I can't say I have ever experienced problems with switch bounce.

Didn't Mark have something similar until he replaced ...mmmm... the 7445? Are you using a 'plain' 7445?
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