Patent ID: 7711993

Claim:
A computer system, comprising: a Joint Test Action Group bus having a plurality of devices connected thereto; a cross point switch that is connected to the Joint Test Action Group (JTAG) bus, wherein the cross point switch is powered up, wherein the cross point switch responds to commands issued on the JTAG bus, wherein the cross point switch is configured by a command that is issued on the JTAG bus, wherein the cross point switch includes a JTAG input and a JTAG output, wherein the cross point switch omits all of the plurality of devices from the JTAG bus when the cross point switch is powered up, wherein the cross point switch connects all of the plurality of devices to the JTAG bus in response to a first command, wherein the cross point switch omits all of the plurality of devices from the JTAG bus in response to a second command, and wherein the cross point switch shorts the JTAG input and the JTAG output in response to all of the plurality of devices being omitted; and a bus controller that is connected to the JTAG bus, wherein the bus controller issues the first command to the cross point switch to connect all of the plurality of devices to the JTAG bus in response to the cross point switch being powered up, and wherein the bus controller issues the second command to reset all connections to omit all of the plurality of devices from the JTAG bus in response to a fault occurring in one of the plurality of devices.