CAPSENSE™ & MagSense Forum Discussions
Hi,
I made a two layer PCB using the CY8CMBR3116 touch controller. I followed all the design guidelines and in particular made the top layer hatched ground plane with 25% fill and the bottom layer hatched ground plane with 17% fill.
The board works, with one odd problem: when I place the PCB on a plastic surface (ABS) so that the bottom layer is against the plastic, then when I press one of the touch sensors, it registers many fake / ghost touches that aren't actually happening. It seems like the smallest bend in the PCB, pushing it closer to the plastic, causes these incorrect button presses to be registered.
When I put some thin packaging foam between the PCB and the plastic, then the problem goes away and the sensors are very accurate.
So I created two new versions of the PCB, with 45% and 65% hatched ground plane fill on the bottom layer - but the problem still happens.
Does anyone know why this could be happening? Could any EZ-Click firmware settings help fix this? Any help appreciated, thanks.
Show LessHi,
Please tell me about the latched_button_stat register latch mechanism in the Cy8cmbr3xxx series? When is the device
Go clear LATCHED_BUTTON_STAT? Thank you.
Show LessHello,
I use capacitive touch buttons with the CY8CMBR3116-LQXI components.
The datasheet recommends parasitic capacitances (Cp) between 5 pF and 45 pF for buttons.
I measure, with the EZ-Click 2.0 software, Cp between 2 pF and 4 pF. Is a Cp value below 5 pF a problem?
For information, I use buttons with a diameter of 9 mm and trace lengths less than 40 mm. The width of the traces is 7 mil (0.17 mm). Button-ground clearance is 2mm (because the glass thickness is 5mm). A hatched pattern is at the top and bottom (2-layer PCB) and it is connected to the SH pin.
Thank you.
Rob
Show LessHello, we are interested in extracting human signs from millimeter-wave radar. After reading the information, we purchased Infineom's BGT60TR13C and downloaded some related components. Can this radar chip currently have a demo to measure heart rate or breathing?
Show LessHi,
We have a PCB using the CY8CMBR3116 touch controller. One thing we noticed is when the customer is pressing a button on power up, the button will not work. We think this is because the IC is calibrating the sensitivity on startup, and it detects the presence of the finger and assumes it is part of the environment, and so increases the threshold.
Is there any way to prevent this? Otherwise, we need to include instructions to our customers to not touch the sensors when powering up the unit...
Also, is it possible to detect a touch is pressed on power up using the registers, and force calibration only after it is removed, using software?
Any help appreciated, thank you.
Show LessUsing CY8CKIT-041S-MAX, CSD TP example code, observe all XY capacitance values measured in measure_cp () between 9000~12000. number_sub_conversion (Nsub) =110.
The Middleware API describes cy_capsense_measurecapacitanceCap () The result is calculated as a specified capacitor capacitance value in picofarads. " "
If it is pF, 9000pF this value is not very likely... The values after Nsub are slightly more reasonable. But the description of middle ware does not mention the need for this action.
If it is FF, it is more reasonable, equivalent to 9~12pF. But the middle ware description clearly says pF...
Is the description of the middle ware API wrong, the unit should be FF? Or do the read capacitor values need to be subtracted from Nsub?
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Hello Guys,
This is İsmet, Im new for cypress, im looking for how can i control this cy8cmbre3110 or 3102 with stm32L431, i found a code with arduino wire.h library can control it with i2c protcol but i have no idea about how to control stm32 with my cy8cmbr3110 or 3102 capsense?
waiting your kind replies!
#capsens #cy8cmbr3110 #stm32 #arduino CY8CMBR3102-SX1IT
Show LessWe have a PCB with 4 capacitive touch pads, two at the top, two at the bottom; using the CY8CMBR3108-LQXIT. We originally bought these ICs ourselves, and assembled the PCBAs by hand in house, never having an issue with the capacitive touch.
However recently going to pre-production we have found 2 of out the 4 capacitive touch buttons never work - both CS6 & CS5 (per the schematic symbol). On all 10 PCBAs we have tested the same pins have failed every time. CS0 & CS1 work fine.
At first we thought this might of been a manufacturing PCB stack-up problem, however if we desolder one of the capsense chips we originally used and assembled ourselves inhouse we and place it onto the production boards, the bottom two buttons now work.
Reading the registers of the broken production PCB, the parasitic capacitance for the top two buttons are about 6pF, the bottom to read 0pF - this indicates to me that there might be a continuity electrical issue, however as mentioned when we replaced it with a known working chip these pins now read 6pF just like the top.
The reason it is concerning is all production PCBs are failing. We need would like to understand why this chip would read 0pF or why they're all damaged.
Things to note:
- Same version of PCB between our one in house and in production (albeit the stack-up is slightly different)
- Putting the production IC on the in-house PCB fails, but putting the in-house IC on the production PCB works - so we don't think its the stack-up.
- We know these are the exact same ICs (both in-house and production) as we read the registers and they report the same thing, from the same family.
- Both in-house and production PCBs use the same firmware.
- The pads denoted CS1 & CS2 work, CS3 & CS4 per the 3D PCB view.
- We attempted to re-reflow the production PCBs but this did not resolve the issue.
My only guess is either some static electricity/voltage spike issue my be damaging the bottom two capacitive touch pins, OR there is some new batch of ICs with differing tolerances and when the parasitic capacitance is too low it defaults to a 0pF reading.
Funnily enough another forum post here is the exact same situation - although it doesn't really have a resolution in the post.
Hi everyone,
I work on CY8CMBR3110 capacitive sensor and I try to write a code in STM32CubeIDE, but STM32L4 and capacitive sensor are not communicate. I think, I did something wrong in code.
Can anyone who has programmed this sensor in STM32CubeIDE help me? Are there any sample codes about it?
Thanks in advance.
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