xwhatsit trouble

[megahertzcoil]

Hi all,

I am hoping someone can help me out with a couple strange issues I am having with my Model F AT with xwhatsit controller. 

The first issue I am having is that I have mapped the caps lock (same location as right ctrl on a 104-key board) key to fn1 in both the base layer and layer1.  I have fn1 mapped to trigger layer1.  The problem is that when I tap the caps lock key, the keyboard seems to get stuck on layer1.  Tapping caps lock again doesn't seem to help.  I have to disconnect the USB from the PC and reconnect to recover from the state.  It seems that the keyboard gets stuck in layer1 and there is no way for me to get it out.

The second issue is likely noise related.  The controller is grounded with just the one screw point on the base plate, no connection on the other side.  I believe that all connections on the ribbon cable are good.  Anyway, when typing quickly, I often get phantom keys.  I had to manually set the calibration to 123 since the auto calibration was choosing 120 and that was making things worse.  The manual calibration helped, but didn't completely remove the issue.  Any ideas on how to fix the issue?  Have others installed additional grounding or shielding?  I want to get this working since I love using the keyboard, but the key press errors are terribly disruptive!

[vivalarevolución]

I have not programmed any of the my Model F's in awhile, but I believe you will need to provide a different key that will allow to you go back to the base layer.

First of all, you are aware of the differences between the Fn keys and the Select keys, correct?  Any chance that you could take a screenshot of your layer conditions page?  For now, perhaps you could add the "Select Base" key code to layer1, so you can return to your Base layer when the keyboard is stuck on layer1 (if you haven't tried that already).

I've had the issue with phantom keys, and I'm thinking that might be a bad controller or bad PCB, because nothing I do seems to solve issue.  Perhaps it would be a good idea to add extra shielding or grounding to the controller and see what happens.  Also, make sure that all your dead keys were identified when you were finding the correct voltage threshold.  You need to find all the dead keys BEFORE using auto calibrate.

[vivalarevolución]

Also, if nobody else responds to help and I forget to respond, send me a PM, I don't venture into the main keyboard forum often.

[megahertzcoil]

Well, I got some help from ellipse.  He pointed me at the modified version of the xwhatsit controller firmware with alternative debounce filtering over at DT: http://deskthority.net/f-o-r-s-a-l-e-f58/xwhatsit-s-grand-unified-ibm-capsense-usb-controller-thread-t7993-900.html?hilit=debounce#p209360.  I wasn't able to reproduce the issue at home with the 0.9.0 firmware but I went ahead and installed the alternative version anyway.  I will see if the problem persists at work this week.  If the problem persists, I will crack the thing open and scope the board and look for sources of noise.

vivalarevolución, thanks for your input.  I actually hadn't realized that there was the select functionality.  Anyway, the issue turned out to be stupid user error.  I thought I had selected the fn1 key to be the same on all layers, but it turns out I assigned the fn1 on layer1 to be the phantom pressed location used for auto-calibration.  Thus, whenever I entered layer1, the fn1 key was always being registered as pressed and the keyboard would get stuck in layer1.  Doh.  It's all working now.

[Melvang]

For what its worth guys, when everytime I setup the threshold on my AT, I never once used the auto calibrate.  Read the info for the software.  It explains how to set that up.  If you still have issues, I asked about some phantom key presses on mine I was getting.  Very intermittent but there.  I only have a range of about 2 that mine works fine.  The ground strap from the bottom plate is much different since my controller is not screwed to the plate like normal. 

My controller is screwed to a steel plate that is screwed to the bottom of my keyboard tray.  To connect the two, I have a jumper wire with a ring connector on both ends.  Just goes to the mount screw on the controller and on the back plate, I silver soldered a motherboard screw and attach with a nut.  If I go two high, I get one key that gives phantom presses not related to any other keyboard activity I can detect, if I go two low, one key doesn't register properly.

[megahertzcoil]

Thanks Melvang.  I was excited about autocalibrate but soon realized that it was setting the threshold too low.  I have the threshold set manually at 122 and it worked flawlessly today, along with the updated firmware.  I will give the rest of the week before making any more adjustments.

Out of curiosity, does the threshold tend to stay steady over time for a particular keyboard?  Is the threshold more a function of the controller or the capacitive pad PCB?  Just wondering what cases autocalibration is needed or helpful.

[Melvang]

Thanks Melvang.  I was excited about autocalibrate but soon realized that it was setting the threshold too low.  I have the threshold set manually at 122 and it worked flawlessly today, along with the updated firmware.  I will give the rest of the week before making any more adjustments.

Out of curiosity, does the threshold tend to stay steady over time for a particular keyboard?  Is the threshold more a function of the controller or the capacitive pad PCB?  Just wondering what cases autocalibration is needed or helpful.

Glad to hear it worked.  I do believe it is a function relating very minor manufacturing differences in trace width, length, thickness and the same with the pads as well.  This coupled with other requirements of capacitive sensing, is why one can't just cut an F pcb down to a different form factor.

[0100010]

Thanks Melvang.  I was excited about autocalibrate but soon realized that it was setting the threshold too low.  I have the threshold set manually at 122 and it worked flawlessly today, along with the updated firmware.  I will give the rest of the week before making any more adjustments.

Out of curiosity, does the threshold tend to stay steady over time for a particular keyboard?  Is the threshold more a function of the controller or the capacitive pad PCB?  Just wondering what cases autocalibration is needed or helpful.

I never used auto-calibration on my F107.  I did have some ghosting issues during the first couple days, cleaned up by raising the threshold a couple points.  From memory it is at 123 or so - haven't touched it in months, no need.

[Melvang]

Thanks Melvang.  I was excited about autocalibrate but soon realized that it was setting the threshold too low.  I have the threshold set manually at 122 and it worked flawlessly today, along with the updated firmware.  I will give the rest of the week before making any more adjustments.

Out of curiosity, does the threshold tend to stay steady over time for a particular keyboard?  Is the threshold more a function of the controller or the capacitive pad PCB?  Just wondering what cases autocalibration is needed or helpful.

I never used auto-calibration on my F107.  I did have some ghosting issues during the first couple days, cleaned up by raising the threshold a couple points.  From memory it is at 123 or so - haven't touched it in months, no need.

My AT is set to 122 iirc. 

[megahertzcoil]

I am happy to report that after installing the modified firmware, I no longer have ghost keys.  So I think I will just leave things alone for the time being.

Thanks everyone for the input.