Uart; Usb; Touch Sensor - Espressif Systems ESP32-S2 Hardware Design Manuallines

3. PCB Layout Design
Figure 17: ESP32­S2 Flash and PSRAM Layout

3.7 UART

The series resistor on the U0TXD line needs to be placed as close to the chip and far from the crystal oscillator as
possible. The U0TXD and U0RXD traces on the top layer should be as short as possible. Employ vias around the
traces for isolation.

3.8 USB

Place the RC circuit reserved on the USB lines close to the chip. Route the USB traces on the inner layer (third
layer) whenever possible. Please use differential routing and make each trace the same length. Make sure there is
a complete reference ground plane. Note to surround the USB traces with ground copper.

3.9 Touch Sensor

ESP32-S2 offers up to 14 capacitive IOs that detect changes in capacitance on touch sensors due to finger contact
or proximity. The chip's internal capacitance detection circuit features low noise and high sensitivity. It allows users
to use touch pads with smaller area to implement the touch detection function. Users can also use the touch panel
array to detect a larger area or more test points. Figure 18 depicts a typical touch sensor application.
Espressif Systems 16 ESP32-S2 Hardware Design Guidelines V1.1
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