there are two 1553 bus drivers implemented the B1553BRM and the GR1553B.
The B1553BRM core is based on a previous ACTEL core that was adapted to the Leon architecture while GR1553B was developed from scratch by Gaisler Research. Both operate in similar manner and can be in three distinct modes: Remote Terminal (RT), Bus Controller (BC) or Bus Monitor (BM).
Similarly to the other cores already detailed, these devices are configured by a set of registers mapped into I/O memory space and transfer data packets directly into and from main memory. The B1553BRM core is only capable of addressing a contiguous memory are of 128Kb; therefore the size and number of buffers used for DMA is limited.
Communication in a MIL-STD-1553B bus occurs between the Bus ontroller and/or Remote Terminals. Each remote terminal occupies one address on the bus and has 31 sub addresses. Sub addresses occupy a similar role to UDP ports and are regularly used for routing inside a remote terminal system. The MIL-STD-1553B standard also defines a special class of commands, named mode codes, that are issued to special sub addresses and which result in special actions like connecting the redundant bus or receiving the onboard time.