Xilinx, Inc.

Madan Mohan Patra

Tuyet Ngoc Simmons

Matthew H Klein

Paul T Sasaki

Jian Tan

Ketan Sodha

Prasad Rau

Testing an integrated circuit (IC) having numerous terminals coupled to numerous digitally controlled impedance (DCI) modules, where the numerous DCI modules control configurable impedances of the numerous terminals. The IC further includes a control circuit having outputs coupled to enable inputs of the numerous DCI modules, where operating the IC in a test mode configures the control circuit to selectively couple a control signal to the enable terminals of the numerous DCI modules. One DCI module of the numerous DCI modules can be enabled at a time facilitating testing of the configurable impedances of the I/O terminals.

Testing an integrated circuit having configurable input/output terminals

An embodiment of a method for operation of an input/output block is disclosed. For this embodiment of the method, a first attribute is set for a first disable signal for an input driver. A first tri-state condition is removed from an output driver. In response to the removing of the first tri-state condition, the input driver is placed in a second tri-state condition.

Input/output block and operation thereof

A circuit has first portion that receives data at a first rate; a second portion that outputs data at a second rate synchronized to and different from the first rate; a third portion that transfers data from the first portion to the second portion; and a fourth portion that generates an error detected signal in response to a disruption in the synchronism between the first and second rates. A different aspect involves a method that includes: receiving data at a first rate in a first portion; transferring data from the first portion to a second portion; outputting data at a second rate from the second portion, the second rate being synchronized to and different from the first rate; and generating an error detected signal in response to detection of a disruption in the synchronism between the first and second rates.

Method and apparatus for detecting and correcting errors in a parallel to serial circuit

A method and apparatus is provided to utilize the configurability of a programmable logic device (PLD), so as to reduce the complexity of special test equipment (STE) fixtures that are required to test the PLD. The output drivers of certain I/O buffers of the PLD that are not under test may be configured to exhibit a particular impedance magnitude. The impedance magnitude of the output drivers that are not under test may then be used to supply the reference impedance that is required by the digitally controlled impedance (DCI) controllers of the I/O buffers that are under test. The DCI controllers may then correctly configure the impedance magnitude of the respective I/O buffers under test, so as to test the functionality of the controlled impedance buffers for I/O standards that require controlled impedance.

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Santa Clara, CA, United States of America

Madan Mohan Patra