The recommended layout and routing for the MPR121QR2 involves keeping the sensor traces as short as possible, using a solid ground plane, and avoiding routing signals under the sensor electrodes. A 4-layer PCB with a dedicated ground plane is recommended.
Calibration involves setting the sensitivity and threshold values for each electrode. This can be done using the MPR121QR2's built-in auto-calibration feature or by manually adjusting the values based on the specific application requirements.
The MPR121QR2 can support up to 12 electrodes, but the maximum number of electrodes that can be connected depends on the specific application and the desired level of sensitivity and accuracy.
Noise and interference can be minimized by using proper shielding, grounding, and filtering techniques. Additionally, the MPR121QR2 has built-in noise filtering and debouncing features that can be enabled to improve performance.
Yes, the MPR121QR2 can be used in a multi-touch application, but it requires additional processing and algorithms to detect and track multiple touch points. The MPR121QR2 provides raw data that can be used to implement multi-touch functionality.
MPR121QR2 datasheet
by Freescale Semiconductor
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