Cisco Technology, Inc.

Cisco Systems Inc.

Crosswell C Collins

Kevin J Rowett

Eric R Buell

Eric Youngman

Kenneth B Finch

A router is integrated onto a single silicon chip and includes an internal bus that couples multiple data receive and transmit channels to a central processing unit. The channels each have an external interface for connecting to different LAN or WAN networks. The serial channels are convertible into one or more time division multiplexed (TDM) channels. A time slot assigner (TSA) assembles and disassembles data packets transferred in TDM formats, such as ISDN. The serial channels are used for separately processing data packets in each TDM time slot. The TSA is programmable to operate with different TDM formats. A single direct memory access controller (DMAC) is coupled to each serial channel and an Ethernet channel and conducts data transfers on the internal router bus through a common port. The DMAC uses a novel bus protocol that provides selectable bandwidth allocation for each channel. The router architecture includes different interface circuitry which is also integrated onto the silicon chip. The interface circuitry includes user definable input/output (I/O) pins with programmable pulse width detection. The user definable I/O provides synchronous and asynchronous interfacing to peripheral devices with different timing constraints. The interface circuitry also includes a DRAM controller having a programmable timing control circuit that operates with memory devices having different timing and memory block sizes.

Network router integrated onto a silicon chip

A memory controller and system for providing access to PCMCIA standard memory cards and non-standard memory cards. Non-standard memory cards are memory cards that are compliant with PCMCIA standards for sockets and are non-compliant in other respects. The memory controller has a register for storing a code that indicates whether a memory card is a PCMCIA card or a non-standard memory card. An access control circuit in the memory controller activates and deactivates memory card control signals at times required by the memory card and as indicated by the memory card type. An acknowledge control circuit generates an acknowledge signal to a requesting processor at a time prescribed by the type of memory card.

Mode selectable memory controller for PCMCIA standard memory cards and

Apparatus and method for a network router

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Oakland, CA, United States of America

Crosswell C Collins