A logic circuit and a technique for repairing faulty memory cells internally by employing on-chip testing and repairing circuits in an ASIC system. The test circuit detects column line faults, row faults, and data retention faults in a memory array. The repair circuit redirects the original address locations of the faulty memory lines to the mapped address locations of the redundant column or row lines. This repair scheme includes redundant column lines attached to each of the I/O arrays in the memory array and redundant row lines to replace detected memory faults. These testing and repairing procedures are performed within the chip without the aid of any external equipment.
A system includes a serial bus 330, at least a first portion of which is formed on a circuit board. A first physical layer controller 322 is coupled to the first portion of serial bus 330. This physical layer controller 322 includes a register set with a plurality of eight-bit registers addressable by four-bit addresses. In this device, at least one of the seventh or eighth bits of the 0010 register is permanently programmed with a logical "1". This physical layer controller is also backward compatible with a physical layer controller that conforms with IEEE-Std-1394-1995. The system also includes another physical layer controller 324, which may or may not be the same as physical layer controller 322, link layer controllers 314 and 316 and at least one processor (or controller) 310.
A built-in programmable self-diagnostic circuit for finding and locating faults in a static random access memory (SRAM) unit. The circuit includes a plurality of multiplexers, a demultiplexer, a test pattern generator, a fault location indicator and a controller. The circuit uses either internal test instructions or pre-programmed test instructions to test the SRAM unit so that the exact location of any fault in the SRAM unit can be found and subsequently repaired.
A repair analysis circuit for redundancy, a redundant method for repairing a redundant, and a semiconductor device that can shorten time for testing defective memory cells, that eliminate the need of failure memories having a huge capacity for storing defective bits to make the testing apparatus inexpensive, and that easily cope with increase and decrease in IO numbers. A large number of IO outputs MOUT are collectively compared with a specified expected value, and as a result resultant judgment information DOUT is outputted to an error information acquiring device 22, and an analyzing device 23 reads table information sequentially from each block to obtain replacing data, and the replacing data are outputted serially to the external tester through the external I/F circuit 24. The redundant memory cell 4a itself can be made to compare with a specified expected value in the same manner as other memory cells 4 or the like. By outputting the result of determination can also be outputted to the error information acquiring device 22 in the same manner as judgment information DOUT for other memory cells 4 or the like, repair analysis can be performed without using any defective redundant memory cells.
A built-in self-repair system includes an on-chip clock generator for triggering the repairing process to repair defective memory lines or blocks in a memory array of an ASIC chip. The on-chip clock generator enables the self-repair process to start at the power up of a computer system without a need for an external test-triggering signal. The system includes a built-in self-test circuit that tests for a defective row memory line or a defective I/O memory block. The system further includes a fault-latching-and repair-execution circuit that repairs a row memory line or an I/O memory block. Repairing an IO memory block effectively repairs faults that occur between any two adjacent column shorts within an IO memory block. The preferred repairing scheme adopts a 15N diagnosis to achieve high fault correction so that a large percentage of defective memory cells can be replaced by redundant row memory lines or redundant I/O memory blocks. The defective row memory lines and I/O memory blocks are dynamically repaired as each of the row memory lines and I/O memory blocks undergoes testing to determine if any defective memory cells exist.
A built-in programmable self-diagnostic circuit for finding and locating faults in a static random access memory (SRAM) unit. The circuit includes a plurality of multiplexers, a demultiplexer, a test pattern generator, a fault location indicator and a controller. The circuit uses either internal test instructions or pre-programmed test instructions to test the SRAM unit so that the exact location of any fault in the SRAM unit can be found and subsequently repaired.
