Crossbar interface for data communication network

摘要

An interface between a host computer and a crossbar switch is provided which employs data buffering using multiple-port RAM devices. The receive and transmit data is clocked into or out of separate serial ports of the RAM, and at the same time a local processor can access the RAM by a random access port, asynchronous to the serial ports, to execute the protocol. The order of storing bursts of data in the multiple-port RAM is defined by a free buffer manager which keeps account of which locations are free. The addresses of these locations are moved to a received list after being used for incoming packets. After the protocol processor has finished with its tasks, these addresses, referred to as burst data descriptors, are moved to a transmit list to await loading of burst data back to the serial registers for clocking out, then when transmitted the descriptors are again entered into the free buffer manager.