Abstract: A multi-bit-per-cell memory reduces the effect of defects and data errors by scrambling data bits before writing data. The scrambling prevents storage of consecutive bits in the same memory cell. When a memory cell is defective or produces an error, the bits read from the memory cell do not create consecutive bit errors that would be noticeable or uncorrectable. An error or a defect in a multi-bit memory cell causes at most scattered bit errors. Scramblers in multi-bit-per-cell memories can include 1) hardwired lines crossing between an input port and an output port, 2) programmable wiring options, 3) a linear buffer where reads from the buffer use addresses with swapped bits, or 4) a buffer array that switches between incrementing a row address first and incrementing a column address first when accessing memory cells in the buffer array.

Abstract: A programmable logic device is presented comprising a global interconnect array whose lines are fed via programmable multiplexers to logic array blocks. The global interconnect array lines are fed to the multiplexers in a specific pattern which maximizes the user's ability to route a selected line to the output of a selected multiplexer, while at the same time maintaining higher speed and lower power consumption, and using less chip array than prior art programmable logic devices using programmable interconnect arrays based on erasable programmable read-only memories.

Abstract: A programmable logic device is presented comprising a global interconnect array whose lines are fed via programmable multiplexers to logic array blocks. The global interconnect array lines are fed to the multiplexers in a specific pattern which maximizes the user's ability to route a selected line to the output of a selected multiplexer, while at the same time maintaining higher speed and lower power consumption, and using less chip array than prior art programmable logic devices using programmable interconnect arrays based on erasable programmable read-only memories.

Abstract: A programmable logic device is presented comprising a global interconnect array whose lines are fed via programmable multiplexers to logic array blocks. The global interconnect array lines are fed to the multiplexers in a specific pattern which maximizes the user's ability to route a selected line to the output of a selected multiplexer, while at the same time maintaining higher speed and lower power consumption, and using less chip array than prior art programmable logic devices using programmable interconnect arrays based on erasable programmable read-only memories.

Abstract: A programmable logic device having a relatively small number of programmable product terms ("P-terms") feeding each fixed combinatorial logic device, and additional "expander" programmable P-terms which do not directly feed a fixed device. Relatively simple logic functions can be performed by suitably programming the P-terms feeding the fixed devices. More complex logic functions can be performed by suitably programming the required number of expander P-terms, and then combining the outputs of those P-terms by means of another P-term. In addition, a programmable interconnect array is provided to allow certain inputs to the device to be applied to any programmable portion of the device, and also to allow the outputs of at least one of the fixed devices to be also applied to any programmable portion of the device.

Abstract: A programmable logic device having a plurality of word lines and a plurality of bit lines, each of which is programmably interconnectable to at least one of the word lines for producing on each bit line a signal which is a logical function of the signal or signals on the word line or lines to which that bit line is interconnected. The logic device further includes at least one spare word line and/or bit line for use in the event that one of the regular lines of the same kind in defective. When the spare line is to be used, the device is preprogrammed to automatically redirect all signals intended for the bad line to another line, thereby putting the spare line into use. The signals thus automatically redirected include both the signals used during program mode to selectively interconnect the word lines and bit lines and the data signals subsequently processed during normal operation of the device.

Abstract: A programmable logic device having a relatively small number of programmable product terms ("P-terms") feeding each fixed combinatorial logic device, and additional "expander" programmable P-terms which do not directly feed a fixed device. Relatively simple logic functions can be performed by suitably programming the P-terms feeding the fixed devices. More complex logic functions can be performed by suitably programming the required number of expander P-terms, and then combining the outputs of those P-terms by means of another P-term. In addition, a programmable interconnect array is provided to allow certain inputs to the device to be applied to any programmable portion of the device, and also to allow the outputs of at least one of the fixed devices to be also applied to any programmable portion of the device.

Abstract: A flip-flop-type circuit capable of operating either as a conventional D flip-flop or as a device which merely passes through the data applied to it (so-called "flow-through mode"). In the flow-through mode, the circuit has the additional capability of being able to latch in the data flowing through it at any time. Thus the circuit can also operate as a level-sensitive latch.