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 (US_LONPR) defines the preamble length. Note that preamble length of ‘0’ is not allowed.

The LON implementation allows two different preamble patterns ALL_ONE and ALL_ZERO which can be configured via US_MAN.TX_PL. The following figure illustrates and defines the valid patterns.

Other preamble patterns are not supported.

Figure 1. Preamble Patterns