Preamble Transmission

Each LON frame begins with a preamble of variable length which consists of a bit-sync field and a byte-sync field. The LONPL field of the USART LON Preamble register (FLEX_US_LONPR) defines the preamble length. Note that a preamble length of ‘0’ is not allowed.

The LON implementation allows two different preamble patterns ALL_ONE and ALL_ZERO which can be configured through the TX_PL field of the USART Manchester Configuration register (FLEX_US_MAN). The following figure illustrates and defines the valid patterns.

Other preamble patterns are not supported.