Neoway WM620 - Level Shifting for UART; Figure 3-18 Recommended Circuit between 3.3 V MCU and UART

WM620 Hardware User Guide
Copyright © Neoway Technology Co., Ltd
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3.5.2 Level Shifting for UART
If the UART is interfacing with a MCU that has 3.3 V logic levels, a resistor should be connected in series
with the signals.
Figure 3-18 Recommended circuit between 3.3V MCU and UART
If the UART is interfaced with an MCU that has 5 V logic levels, level shifting is required for both UART
receive and transmit. Figure 3-19 shows a reference circuit.
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33 pF
33 pF
MCU_UTXD
MCU_URXD
RXD
TXD
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