Capsense Key sense problem for device CY8C24994

[anandkalode]

Dear All,
I am using Cypress device CY8C24994 for sensing 39 keys. I am facing problem to sense all 39 keys.

when i configure device for 27 keys using CSD method. then i can sense 27 keys properly with 3 mm thick acrylic material. As soon as i increase the no of keys form 27 to 28, i can't sense 28th key. i have total 39 keys on my keyboard. when i configure another 27 keys then i can sense another 27 keys without any problem with 3 mm thick resistive material. means my hardware is ok. no issue in hardware.

Another thing is that, when i write a code for 39 keys. without the 3 mm thick resistive material, then i can sense all 39 keys properly.But this dont work with acrylic.

But as soon as i use 3 mm thick resistive material on the keyboard. then i can sense first 27 keys only.

Can anybody please help me. to resolve this problem, and scan all 39 keys with 3 mm thick resistive (acrylic) material.
waiting for reply.

Thanks
Anand kalode.

[graaja]

This will need some debugging of the capsense data. If you have the I2C-USB bridge, you can easily analyze the raw counts using the charting tool. In case, you do not have the I2C-USB bridge, then I would suggest you use a TX8SW user module and transmit the data like Raw Counts, Difference Counts etc and observe on Hyperterminal.