I'm working on a mechanical keypad replacement to get a USB capacitive keypad.
My mechanical keypad controler is CY7C63413C (keyboard controler)
I'm using CY8CMBR2016 to interface the capacitive keypad with the keyboard controler and get lines/columns (READ / SCAN)
I adapted the controler software and it works.
But, when i keep pressing the sensor, I get autorepeat in key (it is normal) and sometimes it sends the wrong key (while I keep pressing the sensor).
I used a logic analyzer (in attachment you will find printscreen)
- normal_scan_MBR2016.jpg :
A normal scan : SCAN go low one after the other and READ is low according on which sensor is touched.
- READ_problem_scan_MBR2016.jpg :
The problem wrote above : SCAN go low one after the other but the READ keep staying low for two cycles. So it is low during two SCAN and my controler reads this as a second key pressed.
- miss_READ_scan_MBR2016.jpg : it is an other problem, when i keep pressing a sensor, sometimes it miss it (so the READ line doesn't go low).
I hope it is clear enough, if not, please, feel free to say,
Many thanks in advance for your feedback !
Solved! Go to Solution.
1. Can you measure the difference counts of each of your buttons and verify that if one button is touched, the other button doesn't have a difference count more than the finger threshold. If this is the case, try increasing the finger threshold.
2. This could also be due to high sensitivity. Try reducing the sensitivity of the buttons.
3. Try using Flanking sensor suppression feature.
4. Check if you have enabled the Button auto reset feature.
Thank you for your reply !
I tried to modify the 3 last points (sensitivity, FSS, ARST) and nothing change.
I will measure the difference count, but what software can I use to debug this chip ?
(The kit has a RS232 interface for debugging)
How should I increase the finger threshold on this chip ?
Many thanks in advance,