Abstract: A communication device configured to communicate according to a data protocol in which data is carried in packets over a serial data link and the communication device is arranged: to form packets for transmission over the link in such a way that every packet commences with a first bit value; and between transmitting successive packets to continuously transmit a second bit value opposite to the first bit value over the link.

Abstract: A method of tracing transactions on an integrated circuit chip. The method comprises, for each transaction: extracting the transaction from interconnect circuitry of the integrated circuit chip, the transaction comprising an address signal and a data signal; applying a filtering condition to the address signal; only if the address signal does not fail the filtering condition, storing the address signal in an address trace buffer; storing the data signal in a data trace buffer; applying a triggering condition to the stored transaction; and outputting the stored transaction if the stored transaction matches the triggering condition.

Abstract: A communication device configured to communicate according to a data protocol in which data is carried in packets over a serial data link and the communication device is arranged: to form packets for transmission over the link in such a way that every packet commences with a first bit value; and between transmitting successive packets to continuously transmit a second bit value opposite to the first bit value over the link.

Abstract: A communication device configured to communicate according to a data protocol in which data is carried in packets over a serial data link and the communication device is arranged: to form packets for transmission over the link in such a way that every packet commences with a first bit value; and between transmitting successive packets to continuously transmit a second bit value opposite to the first bit value over the link.

Abstract: A method of profiling transactions on an integrated circuit chip. The method comprises, for each transaction: extracting the transaction from interconnect circuitry of the integrated circuit chip; and filtering the transaction at a filtering circuit to determine which passband a parameter of the transaction lies within; sending an increment signal to a counter of a bank of counters, the counter having a counter value indicative of a number of transactions having the parameter lying within the passband; and outputting the counter values of the bank of counters.

Abstract: A method of functionality testing system circuitry on an integrated circuit chip, the system circuitry comprising a plurality of sub-circuits and the integrated circuit chip further comprising debugging circuitry, the debugging circuitry comprising variability circuitry. The method comprises: at the system circuitry, performing a function by the sub-circuits performing concurrent actions; at the variability circuitry, altering relative timing of the concurrent actions so as to increase the likelihood of one or more errors in the system circuitry's performance of the function; and at the debugging circuitry, recording one or more errors in the system circuitry's performance of the function.

Abstract: A communication device configured to communicate according to a data protocol in which data is carried in packets over a serial data link and the communication device is arranged: to form packets for transmission over the link in such a way that every packet commences with a first bit value; and between transmitting successive packets to continuously transmit a second bit value opposite to the first bit value over the link.

Abstract: A method of tracing transactions on an integrated circuit chip. The method comprises, for each transaction: extracting the transaction from interconnect circuitry of the integrated circuit chip, the transaction comprising an address signal and a data signal; applying a filtering condition to the address signal; only if the address signal does not fail the filtering condition, storing the address signal in an address trace buffer; storing the data signal in a data trace buffer; applying a triggering condition to the stored transaction; and outputting the stored transaction if the stored transaction matches the triggering condition.

Abstract: A method of profiling transactions on an integrated circuit chip. The method comprises, for each transaction: extracting the transaction from interconnect circuitry of the integrated circuit chip; and filtering the transaction at a filtering circuit to determine which passband a parameter of the transaction lies within; sending an increment signal to a counter of a bank of counters, the counter having a counter value indicative of a number of transactions having the parameter lying within the passband; and outputting the counter values of the bank of counters.

Abstract: An integrated circuit chip device comprising: system circuitry; debugging circuitry configured to debug the system circuitry, the debugging circuitry being segmented into zones; wherein the debugging circuitry comprises an interconnect fabric configured to route debug messages through a zone from a zone entry node of the interconnect fabric to a zone exit node of the interconnect fabric; and wherein the debugging circuitry is configured to, on receiving a debug message at a zone entry node that is shorter than a specified length, modify the debug message to form a modified debug message by increasing the length of the debug message to the specified length.

Abstract: A method of functionality testing system circuitry on an integrated circuit chip, the system circuitry comprising a plurality of sub-circuits and the integrated circuit chip further comprising debugging circuitry, the debugging circuitry comprising variability circuitry. The method comprises: at the system circuitry, performing a function by the sub-circuits performing concurrent actions; at the variability circuitry, altering relative timing of the concurrent actions so as to increase the likelihood of one or more errors in the system circuitry's performance of the function; and at the debugging circuitry, recording one or more errors in the system circuitry's performance of the function.

Abstract: A method of functionality testing system circuitry on an integrated circuit chip, the system circuitry comprising a plurality of sub-circuits and the integrated circuit chip further comprising debugging circuitry, the debugging circuitry comprising variability circuitry. The method comprises: at the system circuitry, performing a function by the sub-circuits performing concurrent actions; at the variability circuitry, altering relative timing of the concurrent actions so as to increase the likelihood of one or more errors in the system circuitry's performance of the function; and at the debugging circuitry, recording one or more errors in the system circuitry's performance of the function.

Abstract: An integrated circuit chip device comprising: system circuitry; debugging circuitry configured to debug the system circuitry, the debugging circuitry being segmented into zones; wherein the debugging circuitry comprises an interconnect fabric configured to route debug messages through a zone from a zone entry node of the interconnect fabric to a zone exit node of the interconnect fabric; and wherein the debugging circuitry is configured to, on receiving a debug message at a zone entry node that is shorter than a specified length, modify the debug message to form a modified debug message by increasing the length of the debug message to the specified length.

Abstract: A method of validating functional testing of system circuitry on an integrated circuit chip, the system circuitry configured to perform a plurality of functions, the integrated circuit chip further comprising debugging circuitry under the control of a debug controller, the debugging circuitry comprising at least one debug unit. The method comprises: at the system circuitry, performing one of the plurality of functions; applying a debug configuration to the at least one debug unit; and at the at least one debug unit, monitoring for a characteristic in the system circuitry's performance of the one of the plurality of functions according to that debug configuration, and reporting to the debug controller.

Abstract: A method of validating functional testing of system circuitry on an integrated circuit chip, the system circuitry configured to perform a plurality of functions, the integrated circuit chip further comprising debugging circuitry under the control of a debug controller, the debugging circuitry comprising at least one debug unit. The method comprises: at the system circuitry, performing one of the plurality of functions; applying a debug configuration to the at least one debug unit; and at the at least one debug unit, monitoring for a characteristic in the system circuitry's performance of the one of the plurality of functions according to that debug configuration, and reporting to the debug controller.

Abstract: A method of functionality testing system circuitry on an integrated circuit chip, the system circuitry comprising a plurality of sub-circuits and the integrated circuit chip further comprising debugging circuitry, the debugging circuitry comprising variability circuitry. The method comprises: at the system circuitry, performing a function by the sub-circuits performing concurrent actions; at the variability circuitry, altering relative timing of the concurrent actions so as to increase the likelihood of one or more errors in the system circuitry's performance of the function; and at the debugging circuitry, recording one or more errors in the system circuitry's performance of the function.