Patent ID: 8078927

Claim:
An integrated circuit comprising: A. a test access port having:\ i. a TDI lead, a TDO lead, a TMS lead, and a TCK lead; ii. a test access port controller having inputs connected to the TMS and TCK leads and having an instruction register and data register control bus output; iii. a test access port instruction register having a TDI input connected to the TDI lead, control inputs connected to the instruction register and data register control bus output of the test access port controller, a first gating control lead, and a second gating control lead; iv. a data register having a TDI input connected to the TDI lead, control inputs coupled to the instruction register and data register control bus output of the test access port controller, and a TDO output selectively coupled to the TDO lead; and v. first gating circuitry having first inputs connected with the instruction register and data register control bus output, having second inputs, outputs connected with the control inputs of the data register, and a control input connected with the first gating control lead; B. an auxiliary test control bus of leads separate from the TDI lead, the TDO lead, the TMS lead, and the TCK lead; and C. second gating circuitry having a first set of inputs connected with at least part of the instruction register and data register control bus output, a second set of inputs connected with the auxiliary test control bus of leads, outputs connected to the second inputs of the first gating circuitry, and a control input connected with the second gating control lead.