Hello, deavteam. This is MANGO.
The Capacitive Touch on the nRF52 series blog post is really impressive.
I'm planning to start a haptic driver project using TI's DRV2605 driver, an LRA (Linear Resonant Actuators), and Nordic's nRF52 MCU in the 4th quarter of 2018 or 1st quarter of 2019.
The DRV2605EVM-CT evaluation board provided 6 capacitive circle buttons.
Replacing the MSP430, which is populated on the evaluation board, to the nRF52 for my custom PCB is my main objective.
Although the erratum 84 (COMP: ISOURCE not functional) sound daunting to me,
I think there might be a chance for that anomaly to be fixed and see a button sensor reference design that has
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low power consumption
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low Parasitic Capacitance (Cp)
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SNR (ratio of capacitive touch signal to noise) greater than or equal to 5:1
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Annular gap (the air gap between the sensor and ground) considering decreased noise immunity
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Hatch ground fill, connected to a ground shield, to reduce the Cp (surrounding the sensor + PCB bottom layer)
Since nRF52 supports NFC-A, a feature required for my project, choosing other Bluetooth chip vendors is not an option for me.
in short,
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Just like the GitHub nRF5 reference design, are there any plans to upload an Eagle/Altium design project on GitHub to demonstrate a reference design for capacitive touch applications?
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Is there any news about the erratum 84? If that anomaly can be fixed,
users might expect 2 reference design; RC charge timing / Relaxation oscillator application design
- If there are plans to create the reference design, can a tutorial be provided together to create the touch sensor layout using EAGLE or Altium?
EAGLE doesn't allow copper to be placed in a device footprint, except for SMD pads. If you try, DRC will complain about it.
I had difficulties handling the layout, so I was curious how the deavteam handles this problem.
-Best regards, MANGO