An integrated circuit provides for a connection port having a serial data input pin and a serial data output pin, on-chip functional circuitry and test logic, and a test access port controller connected to effect communication of serial data across the chip boundary via said input and output pins. The test access port controller is connectable to the test logic in a first mode of operation to effect communication of serial test data under control of an incoming clock signal and is operable in a second mode of operation to communication data as a sequence of serial bits according to a predetermined protocol between the connection port and the on-chip functional circuitry. The integrated circuit includes an error detection circuit for detecting an error condition in the protocol and gating circuitry responsive to detection of the error condition to prevent communication of subsequent data until the error condition is detected as having been removed.
A system for controlling communications between a host and a target, the system having a data input for receiving a data signal, a clock input for receiving a clock signal, an oversampling circuit for sampling a received data signal and generating a control signal to control processing of the received data signal based at least in part on samples of the received data signal.
A method, apparatus and program storage device for automatically presenting status from a host bus adapter until an error is detected is provided. Data is transmitted between the host bus adapter and a host. The host performs data transmission validation and determines whether data transmission was successful. The host bus adapter automatically sends status information when data transmission was successful, else the host bus adapter waits for status type identification from the host for transmission of data.
A system and method for providing efficient block transfer operations through a test access port uses a Fastdata register. The Fastdata register, in part, emulates a pending process access bit ("PrAcc") typically found in a Control register associated with the test access port. When a Fastdata access (either a Fastdata upload or a Fastdata download) is requested by a probe coupled to the test access port, the Fastdata register is serially coupled to a data register also associated with the test access port. With these registers so coupled and through the operation of the Fastdata register, downloading and uploading data can be accomplished using a single register operation.
