Abstract: A method and apparatus for congestion and fault management with time-to-live (TTL) have been disclosed. Each time a packet is transferred into an Egress Port's Final Buffer, an associated TTL Timeout Counter will be loaded with a value. If the packet cannot be transferred out of the Egress Port before TTL timeout, it will be purged by removing a memory buffer pointer from the corresponding Virtual Output Queue (VOQ) entry.

Abstract: In accordance with the invention, time slot interchange switches (“TSIS”) with bit error rate testing are described. The bit error rate testing includes creating a channel of data appropriate for bit error rate testing and monitoring the bit error rate testing on that channel.

Abstract: Multi-Q FIFO memory systems include a plurality of multi-Q first-in first-out (FIFO) memory chips electrically coupled to a data output bus. The plurality of multi-Q FIFO memory chips, which are responsive to respective identification codes ID and respective read chip select signals (/RCS), are configured to support an enhanced multi-chip expansion mode of operation. This expansion mode of operation uses the read chip select signals to control one-at-a-time access of at least two selected multi-Q FIFO memory chips receiving equivalent ID codes and equivalent read addresses to the output data bus during read operations.

Abstract: A flag logic circuit includes a first comparator configured to generate a first flag value associated with an active read queue of a multi-queue memory device, and a second comparator configured to generate a second flag value associated with an active write queue of the multi-queue memory device. A dual-port memory is adapted to store a flag value for each queue of the multi-queue memory device. The dual-port memory has a first write port configured to receive the first flag value and a second write port configured to receive the second flag value. A first stage storage element is configured to latch each of the flag values stored in the dual-port memory in response to a first clock signal, such that the flag values are synchronized on an active status bus and flag status bus.

Abstract: A multi-queue memory system is configured to operate in a packet mode. Each packet includes a SOP (start of packet) marker and an EOP (end of packet) marker. A packet status bit (PSB), is used to implement the packet mode. The packet status bit enables partial packet write and partial packet read operations, such that a queue switch can be performed in the middle of packet write or packet read operations. The packet status bit also enables data filtering to be performed between an activated EOP marker and a subsequently received SOP marker (i.e., between the end of one packet and the start of the next packet). Packet mark and re-write and packet mark and re-read operations are also enabled.

Abstract: In a multi-queue memory system, a plurality of read count pointers (one for each queue) are stored in a read address file, and used to generate empty flags. A read count pointer associated with a first queue is retrieved from the read address file, and it is determined whether the first queue should be available for a re-read operation. If so, the retrieved read count pointer is stored as a first read mark value. The read count pointer is incremented in response to each read operation performed from the first queue, thereby creating an adjusted read count pointer. If a re-read operation is to be performed from the first queue, the first read mark value is stored in the read address file. Otherwise, the adjusted first read count pointer is stored in the read address file. Similar operations are performed on the write side of the multi-queue memory system.

Abstract: A multi-queue memory system includes first and second memory blocks. The first memory block includes a first array of memory cells, a first sense amplifier circuit and a second sense amplifier circuit. The second memory block includes a second array of memory cells, a third sense amplifier circuit and a fourth sense amplifier circuit. Each of the sense amplifier circuits is independently controlled. Each queue of the multi-queue system has entries in both the first and second memory blocks. A first queue is accessed by alternately accessing the first and second arrays via the first and third sense amplifier circuits. A second queue is subsequently accessed by alternately accessing the first and second arrays via the second and fourth sense amplifier circuits.

Abstract: A write counter provides a write count value synchronized with a write clock signal. A read counter provides a read count value synchronized with a read clock signal. The read and write count values are routed through logic, which introduces noise to these values. A first delay circuit generates a first blanking signal, which has a duration corresponding with the duration of the noise introduced to the write count value, in response to the write clock signal. A second delay circuit generates a second blanking signal, which has a duration corresponding with the duration of the noise introduced to the read count value, in response to the second clock signal. The read and write count values are latched into read and write blanking registers, respectively, in response to the first and second blanking signals, respectively, effectively filtering the introduced noise prior to a subsequently performed comparison operation.

Abstract: A method of operating a multi-queue device, including: (1) storing a plurality of read (write) count pointers, wherein each of the read (write) count pointers is associated with a corresponding queue of the multi-queue device, (2) providing a read (write) count pointer associated with a present queue to read (write) flag logic, (3) adjusting the read (write) count pointer associated with the present queue in response to each read (write) operation performed by the present queue, (4) indicating a read (write) queue switch from the present queue to a next queue, (5) retrieving a read (write) count pointer associated with the next queue; and then (6) simultaneously providing the read (write) count pointer associated with the present queue and the read (write) count pointer associated with the next queue to the read (write) flag logic.

Abstract: A multi-queue FIFO memory device that uses existing pins of the device to load a desired number of queues (N) into a queue number register is provided. The queue number register is coupled to a queue size look-up table (LUT), which provides a queue size value in response to the contents of the queue number register. The queue size value indicates the amount of memory (e.g., the number of memory blocks) to be included in each of the N queues. The queue size value is provided to a queue start/end address generator, which automatically generates the start and end address associated with each queue in response to the queue size value. These start and end addresses are stored in queue address register files, which enable proper memory read/write and flag counter operations.

Abstract: A flag logic circuit is provided for use in a multi-queue memory device having a plurality of queues. A first stage memory stores a flag value for each of the queues in the multi-queue memory device. Flag values are routed from the first stage memory to a flag status bus having a width N in the manner described below. A status bus control circuit receives a signal that identifies the number of queues M actually used by the multi-queue memory device, and in response, generates a repeating pattern of X control values, wherein X is equal to (M?(M mod N))/N+1. A selector circuit sequentially routes X sets of N flag values from the first stage memory to the flag status bus in response to the repeating pattern of X control values. The X sets of N flag values include the flag values associated with the queues actually used.

Abstract: In accordance with the invention, time slot interchange switches (“TSIS”) with bit error rate testing are described. The bit error rate testing includes creating a channel of data appropriate for bit error rate testing and monitoring the bit error rate testing on that channel.