UART Serial Communication

Two wires, no clock, and an agreed speed.

UART sends bytes one bit at a time over a transmit line and a receive line. Both ends must use the same baud rate, such as 9600 or 115200 bits per second.

Each byte is framed by a start bit, usually eight data bits, and a stop bit. Connect TX of one device to RX of the other and share a ground.

Mixing 3.3 V and 5 V devices can damage the lower-voltage chip, so check logic levels first.