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Author Topic: Pokeys57CNC Problem with Matrix Keyboard  (Read 1072 times)

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Pokeys57CNC Problem with Matrix Keyboard
« on: March 17, 2018, 08:20:23 AM »
Hi All,

I have Mach3 running with a Pokeys57CNC board. It has 3 axis motor controlling 3 servo motors, PWM 10V analogue driving the spindle, and all the limit, home and E-Stop switches are all working fine. So far so good, the 57CNC has been a great board and rather straight forward to configure.

However, I recently added a small matrix keyboard 3x4 and this is giving me significant trouble to get up and running.

It works, but VERY badly. If I press a key, it registers after about 2-3 seconds. If I hold the button down, then it works maybe 3 times every 10 seconds and very unreliably. I've followed the setup description in the manual, there are no external components (so no external pull up resistors for example) just the buttons wired in a matrix for the keyboard. I also implemented the trivial 1x1 matrix and it shows the same behaviour.

To see the operation of a button, I used both Mach3 and directly with the Pokeys configuration tool. Both show the same behaviour, so I doubt it's directly a Mach3 related issue, apart from the configuration mentioned above.

Any help with this would be appreciated.

Re: Pokeys57CNC Problem with Matrix Keyboard
« Reply #1 on: March 17, 2018, 02:08:41 PM »
Hi All,

Just a further comment about what I've found.
I set the 4x3 matrix with rows using pins: 29, 30, 25, 23
And Columns 3, 4, 26

The buttons which use pin 26 as column work reliably.
The buttons which use pins 3 or 4 are terribly unreliable.

Am I missing something here. Are pin 3 and 4 special in some way. Should I avoid using them. What pins can I use for the keyboard matrix and which ones should I avoid.

Thanks in advance.

Re: Pokeys57CNC Problem with Matrix Keyboard
« Reply #2 on: March 17, 2018, 05:30:39 PM »
Hi All,

OK, it's now resolved. I replaced input pins 3,4 with 18 and 28. It's a shame because I had 18 ,28 marked for something else.
So what's the difference between these pins?

Pins 3 and 4 are type DI33P and pins 18 and 28 are type DI033. Both are input pins but the DI33P are filtered and I suspect the filtered inputs were making the keyboard scanning reading unreliable.

What I'm surprised about is there seems to very little about this issue on the net - not that I could find anyway.

Hope this helps anybody else with a similar problem.