At-speed test access port operations

A device comprising:

• a test data in (TDI) terminal;
• a test data out (TDO) terminal;
• a test mode select (TMS) terminal;
• a test clock (TCK) terminal;
• test compression architecture including:
• a decompressor including an input coupled to the TDI terminal, wherein the decompressor further includes an output;
• parallel data registers coupled to the output of the decompressor;
• a compressor including an input coupled to the parallel data register, wherein the compressor further includes an output coupled to the TDO terminal;
• a router circuit coupled to the parallel data registers;
• a test access port (TAP) state machine coupled to the router circuit, coupled to the TMS terminal, and coupled to the TCK terminal;
• and
• a command circuit coupled to the router circuit, coupled to the TMS terminal, and coupled to the TCK terminal.

A device comprising:

• a test data in (TDI) terminal;
• a test data out (TDO) terminal;
• a test mode select (TMS) terminal;
• a test clock (TCK) terminal;
• test compression architecture including:
• a decompressor including an input coupled to the TDI terminal, wherein the decompressor further includes an output;
• parallel data registers coupled to the output of the decompressor;
• a compressor including an input coupled to the parallel data register, wherein the compressor further includes an output coupled to the TDO terminal;
• a router circuit coupled to the parallel data registers;
• a test access port (TAP) state machine coupled to the router circuit, coupled to the TMS terminal, and coupled to the TCK terminal, wherein the TAP state machine is configured to receive TMS inputs from the TMS terminal on a first edge of a TCK signal received from the TCK terminal;
• and
• a command circuit coupled to the router circuit, coupled to the TMS terminal, and coupled to the TCK terminal,
• wherein the command circuit is configured to:
• receive command inputs from the TMS terminal on a second edge of the TCK signal, wherein the first edge of the TCK signal is different from the second edge of the TCK signal;
• receive a command from the TMS terminal while the TAP state machine is operating in a shift state;
• and
• cause, in response to the received command, the parallel data registers to operate in a capture state while the TAP state machine is operating in the shift state.