Browse Prior Art Database

Smart Network Controller

IP.com Disclosure Number: IPCOM000037078D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 3 page(s) / 44K

Publishing Venue

IBM

Related People

Kulesza, JD: AUTHOR

Abstract

Disclosed is a method for high speed serial communication between a computer host and multiple networks of microprocessors using a smart network controller.

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Smart Network Controller

Disclosed is a method for high speed serial communication between a computer host and multiple networks of microprocessors using a smart network controller.

The method employs a smart, microprocessor-based network controller-to- manager parallel communications with the host and a network of slave microprocessors all on a multi-drop serial link. The smart controller is based on an Intel RUPI* single-chip microprocessor that has on chip both a serial controller and 8051 processing unit. The serial controller uses the SDLC protocol and can achieve 3.4 Mbaud in the clocked mode. The network interface uses the RS485 multi-drop format which limits the number of slaves in a network to 44. The network controller communicates to the host through a parallel DI/DO interface to the 8051. The 8051 communicates with the on-chip serial controller through a shared RAM interface which is also on chip.

The slave units in the network must also use the Intel 8744 to convert the serial messages back to parallel and pass them to the 8051 for execution. The function of the slave processor is not restricted.

The host will only communicate with the network controller; however, the host can select a slave in the network with a software address that the network recognizes and uses to pass the message. Only the host can initiate communications; however, once established, communication is two ways and the operation of the network controller is transparent. Other functions, such as network broadcast and active slave addresses, can be performed by the network controller on command from the host. The type of host processor is not restricted.

Multiple network controllers can be used to expand the total number of slaves. Refer to the Figure. Up to 255 network controllers can be addressed by the Host. If each network has the maximum of 44 slaves, then 11,...