8N1

8N1 stands for 8 data bits, No parity, 1 stop bit. It describes an asynchronous serial data frame used by UARTs and many legacy communication interfaces such as RS-232, RS-422, and RS-485. In an 8N1 frame, the transmitter sends a start bit (logic 0) to signal the beginning of a frame, followed by eight data bits sent least-significant bit first, no parity bit, and a single stop bit (logic 1) to mark the end. The frame occupies ten bit times, which determines the timing at a given baud rate.

8N1 is a widely used default configuration because it provides a straightforward and widely compatible data path. Its simplicity makes it common in personal computers, embedded systems, and microcontroller communications. Since there is no parity bit, error detection relies on higher-layer protocols or higher-level checksums rather than hardware parity.

The 8N1 configuration can be contrasted with other common frames, such as 7E1 (7 data bits, even parity, 1 stop) or 8O1 (8 data bits, odd parity, 1 stop), and 8N2 (8 data bits, no parity, 2 stop bits). The presence or absence of parity and the number of stop bits affect error detection and timing but not the fundamental start/data/stop structure.

In practice, configuring a serial port or UART to 8N1 ensures broad compatibility with modern devices, PC software, bootloaders, and many embedded peripherals that expect a standard asynchronous frame. Proper operation depends on matching baud rate and frame format on both ends of the communication link.