Enumeration Members

Enumeration Members

CANCEL

Terminates a frame in progress.

A Cancel Byte causes all data received since the previous Flag Byte to be ignored. Note that as a special case, RST and RSTACK frames are preceded by Cancel Bytes to ignore any link startup noise.

ESCAPE

Indicates that the following byte is escaped.

If the byte after the Escape Byte is not a reserved byte, bit 5 of the byte is complemented to restore its original value. If the byte after the Escape Byte is a reserved value, the Escape Byte has no effect.

FLAG

Marks the end of a frame.

When a Flag Byte is received, the data received since the last Flag Byte or Cancel Byte is tested to see whether it is a valid frame.

SUBSTITUTE

Replaces a byte received with a low-level communication error (e.g., framing error) from the UART.

When a Substitute Byte is processed, the data between the previous and the next Flag Bytes is ignored.

XOFF

Stop transmission.

Used in XON/XOFF flow control. Always ignored if received by the NCP

XON

Resume transmission.

Used in XON/XOFF flow control. Always ignored if received by the NCP.