UART Protocol
By Dangremont JaysonAbout the author (in French)
UART framing, baud-rate generation, oversampling and VHDL implementation points.
UART sends frames without a shared clock. TX transmits and RX receives independently. On a point-to-point link, both devices must agree on baud rate and frame format.
| Signal | Description |
|---|---|
| TX | Transmit - data sent |
| RX | Receive - data received |
| GND | Common ground (required) |
Read a frame
The line is high at idle. Start holds it low for one bit period, followed by data, optional parity and a high stop level. Common formats use five to nine data bits and one or two stop bits. Data normally travels LSB first.