In-line SCSI bus circuit for providing isolation and bi-directional communication between two portions of a SCSI bus
First Claim
1. A system for communicating data bidirectionally over a data bus within a data bus specification and for isolating said bus, said system comprising,a first means for communicating said data,a second means for communicating said data,bus means having a first portion connected to said first means and a second portion connected to said second means, both of said portions of said bus means for bidirectional transparent communication of said data between said first means for communicating said data and said second means for communicating said data within said data bus specification, andan isolation means connected in-line between said first and second portions of said bus means for isolating said first and second portions of said bus means from each other and for communicating said data between said first and second portions of said bus means, said isolation means comprising first set of line drivers connected to said first portion of said bus means, comprising second set of line drivers connected to said second portion of said bus means, and comprising a control means physically disposed in-line between said first and second portions of said bus means for disabling said first and second sets of line drivers for isolation of said first and second portions of said bus means from each other, said control means also for sensing said bus means and determining direction of said bidirectional transparent communication of said data and for then enabling at least a portion of said first set of line drivers and disabling at least a respective portion of said second set of line drivers and by disabling at least another portion of said first set of line drivers and enabling at least another respective portion of said second set of line drivers so as to enable said bidirectional transparent bus communication through first and second sets of line drivers.
1 Assignment
0 Petitions
Accused Products
Abstract
An in-line SCSI bus isolation circuit includes two ports for transparently communicating bidirectional data and controls signals therebetween during normal operation using respective dedicated sets of line drivers which may be data bit-by-bit and control signal-by-signal selectively enabled and disabled to permit the bidirectional transparent SCSI communications, and which may be completely disabled to electrically isolate a connected SCSI device on a first SCSI port from the other remaining connected SCSI components on the second SCSI port, so that that device may be removed or inserted onto the SCSI bus at the first port when the line drivers are disabled to prevent the voltage transient signals generated on the first SCSI port from being propagated to the second SCSI port connected to the other SCSI components prior to enabling the line drivers and bidirectional SCSI communications between the two SCSI ports.
-
Citations
18 Claims
-
1. A system for communicating data bidirectionally over a data bus within a data bus specification and for isolating said bus, said system comprising,
a first means for communicating said data, a second means for communicating said data, bus means having a first portion connected to said first means and a second portion connected to said second means, both of said portions of said bus means for bidirectional transparent communication of said data between said first means for communicating said data and said second means for communicating said data within said data bus specification, and an isolation means connected in-line between said first and second portions of said bus means for isolating said first and second portions of said bus means from each other and for communicating said data between said first and second portions of said bus means, said isolation means comprising first set of line drivers connected to said first portion of said bus means, comprising second set of line drivers connected to said second portion of said bus means, and comprising a control means physically disposed in-line between said first and second portions of said bus means for disabling said first and second sets of line drivers for isolation of said first and second portions of said bus means from each other, said control means also for sensing said bus means and determining direction of said bidirectional transparent communication of said data and for then enabling at least a portion of said first set of line drivers and disabling at least a respective portion of said second set of line drivers and by disabling at least another portion of said first set of line drivers and enabling at least another respective portion of said second set of line drivers so as to enable said bidirectional transparent bus communication through first and second sets of line drivers.
-
6. An in-line isolation circuit for isolating a first device connected on a first portion of a data bus from a second device connected on a second portion of said data bus, said in-line isolation circuit also for bidirectional transparent communication of said data between said first and second devices through said data bus, said in-line isolation circuit comprising
a first set of line drivers connected to said first portion of said data bus for communicating said data to said first device, a second set of line drivers connected to a second portion of said data bus for communicating said data to said second device, and a control means physically disposed in-line between said first and second portions of said data bus for disabling said first and second sets of line drivers for isolation of said first and second portions of said data bus from each other, said control means also for sensing said data bus and determining direction of said bidirectional transparent communication of said data and for then enabling at least a portion of said first set of line drivers and disabling at least a respective portion of said second set of line drivers and by disabling at least another portion of said first set of line drivers and enabling at least another respective portion of said second set of line drivers so as to enable said bidirectional transparent bus communication through first and second sets of line drivers.
-
11. A method of isolating a first device from a second device connected together through a data bus bidirectionally communicating data signals and control signals, said data bus separated into a first portion and a second portion by an in-line isolation circuit having a first port connected to said first portion of said data bus connected to said first device and a second port connected to said second portion of said data bus connected to said second device, said in-line isolation circuit having a first set of data line drivers and a first set of control line drivers for said first port and having a second set of data line drivers and a second set of control line drivers for said second port, said in-line isolation circuit having a control means physically disposed in-line between said first and second portions of said data bus to disable for isolation and enable for transparent bidirectional communication both first and second sets of said data line drivers and said control line drivers, each data line driver of said first and second sets of data line drivers are selectively enabled and disabled, at least two control line drivers of each of said first and second sets of control line drivers are selectively enabled and disabled, communication through said data bus is provided by enabling line drivers of said first set of line drivers and disabling respective line drivers of said second sets of data line drivers and by enabling line drivers said second set line drivers and disabling respective line drivers of said first set of line drivers, said method comprising the steps of,
data disabling said first and second sets of data line drivers, control disabling said first and second sets of control line drivers, the disabling of said first and second sets of data line drivers and said first and second sets of control line drivers electrically isolating said first and second devices from each other through said data bus, sensing said data signals and said control signals for determining direction of said bidirectional transparent communication, data enabling by enabling at least one of said first set of data line drivers and disabling a respective one of said second set of data line drivers for one communication direction or by enabling at least one of said second set of data line drivers and disabling a respective one of said first set of data line drivers for another communication direction to enable the communication of a respective at least one data signal of said data signals between said first and second devices, and control enabling by enabling at least one of said first set of control line drivers and disabling a respective one of said second set of control line drivers for one communication direction or by enabling at least one of said second set of control line drivers and disabling a respective one of said first set of control line drivers for another communication direction to enable communication of a respective at least one control signal of said control signals between said first and second devices.
Specification