57.7.9.5.3 Preamble Reception

LON received frames begin with a preamble of variable length. The receiving algorithm does not check the preamble length, although a minimum of length of 4 bits is required for the receiving algorithm to consider the received preamble as valid.

As is the case with LON preamble transmission, two preamble patterns (ALL_ONE and ALL_ZERO) are allowed and can be configured through the RX_PL field of the USART Manchester Configuration register (FLEX_US_MAN). The above figure illustrates and defines the valid patterns.

Other preamble patterns are not supported.