A system comprises a plurality of components, scan chain selection logic coupled to the components, and override selection logic coupled to the scan chain selection logic. The scan chain selection logic selects various of the components to be members of a scan chain under the direction of a host computer. The override selection logic detects a change in the scan chain and, as a result, blocks the entire scan chain from progressing.

A scan chain circuit includes first through N-th flip-flops connected in series to sequentially transfer data in response to a control signal, where N is an integer greater than 1. In the first through N-th flip-flops, the data are transferred in a first direction from the first flip-flop to the N-th flip-flop. The control signal is applied to the first through N-th flip-flops in a second direction opposite to the first direction from the N-th flip-flop to the first flip-flop.

An aspect relates to an integrated circuit (IC), including: a data path; a logic gate including a first input coupled to the data path, and a second input configured to receive a second input configured to receive a test data register (TDR) signal; and a first flip-flop including a data input coupled to an output of the logic gate. Another aspect relates to integrated circuit (IC), including: a first logic gate including a first input configured to receive a test data register (TDR) signal; a first flip-flop including a data input (D) coupled to an output of the first logic gate, and a data output (Q) coupled to a second input of the first logic gate; a first data path; and a second logic gate including a first input coupled to the data output of the first flip-flop and a second input coupled to the first data path.

A stack type semiconductor apparatus may be provided. The stack type semiconductor apparatus may include a plurality of semiconductor chips stacked and configured for transferring signals through through-hole vias. Each of the plurality of stacked semiconductor chips may include an error detection circuit configured to perform a down scan for transferring a signal to a lower direction and an up scan for transferring a signal to an upper direction through through-hole vias in a column direction among the through-hole vias, and to determine whether the through-hole vias have failed according to a down scan result value and an up scan result value.

The disclosure describes a novel method and apparatus for testing different types of TSVs in a single die or different types of TSV connections in a stack of die. The testing is facilitated by test circuitry associated with each type of TSV. The test circuitry includes a scan cell adapted for testing TSVs.

Topology discovery of a target system having a plurality of components coupled with a scan topology may be performed by driving a low logic value on the data input signal and a data output signal of the scan topology. An input data value and an output data value for each of the plurality of components is sampled and recorded. A low logic value is then scanned through the scan path and recorded at each component. The scan topology may be determined based on the recorded data values and the recorded scan values.

The disclosure describes a novel method and apparatus for improving silicon interposers to include test circuitry for testing stacked die mounted on the interposer. The improvement allows for the stacked die to be selectively tested by an external tester or by the test circuitry included in the interposer.

An integrated circuit is configured to receive a test clock input and includes circuitry configured to generate test clocks from the test clock input, and test circuitry configured to use the test clocks in a test mode.

A master controller includes: an interface to a CPU, an input port configured to receive a digital signal, and an output port configured to transmit a digital signal. Slave controllers each include: an interface to a device, an input port configured to receive a digital signal, and an output port configured to transmit a digital signal. A first chain bridge includes: a first set of input and output ports that couple the first chain bridge to a first chain of nodes each coupled to neighboring nodes by conductor paths in a closed loop, where the nodes of the first chain include the master controller, and a second set of input and output ports that couple the first chain bridge to a second chain of nodes each coupled to neighboring nodes by conductor paths in a closed loop, where the nodes of the second chain include multiple slave controllers.

A system comprises a plurality of components, scan chain selection logic coupled to the components, and override selection logic coupled to the scan chain selection logic. The scan chain selection logic selects various of the components to be members of a scan chain under the direction of a host computer. The override selection logic detects a change in the scan chain and, as a result, blocks the entire scan chain from progressing.