Abstract: A dual-master controller includes a plurality of JTAG data registers including a controller-mode register that stores information indicating a standard JTAG or a processor-controlled mode of operation. A JTAG TAP controller receives control signals over a standard test access port and a processor controller receives processor control signals over an external processor bus. A selection multiplexer outputs either signals on the standard JTAG access port or the external processor bus responsive to a JTAG mode selection signal. A logic circuit activates the JTAG mode selection signal responsive to the force JTAG signal being active or information in the controller-mode register indicating the standard JTAG mode, and deactivates the JTAG mode selection signal responsive to the force JTAG signal being deactivated or the information in the controller-mode register indicating the processor-controller mode.

Abstract: A dual-master controller includes a plurality of JTAG data registers including a controller-mode register that stores information indicating a standard JTAG or a processor-controlled mode of operation. A JTAG TAP controller receives control signals over a standard test access port and a processor controller receives processor control signals over an external processor bus. A selection multiplexer outputs either signals on the standard JTAG access port or the external processor bus responsive to a JTAG mode selection signal. A logic circuit activates the JTAG mode selection signal responsive to the force JTAG signal being active or information in the controller-mode register indicating the standard JTAG mode, and deactivates the JTAG mode selection signal responsive to the force JTAG signal being deactivated or the information in the controller-mode register indicating the processor-controller mode.

Abstract: A variable latency interface and method for managing variable latency. An apparatus includes a storage device controller and a read/write channel coupled to the storage device controller by a variable latency interface. The variable latency interface includes a media control component configured for read and write operations. The variable latency interface also includes a data transfer component configured for read and write operations. A read or write operation in the media control component is offset from a respective read or write operation in the data transfer component by a latency period.

Abstract: A variable latency interface and method for managing variable latency. An apparatus includes a storage device controller and a read/write channel coupled to the storage device controller by a variable latency interface. The variable latency interface includes a media control component configured for read and write operations. The variable latency interface also includes a data transfer component configured for read and write operations. A read or write operation in the media control component is offset from a respective read or write operation in the data transfer component by a latency period.