Lattice Semiconductor Corporation

Kuang Chi

Om P Agrawal

Jinghui Zhu

Chienkuang Chen

Ju Shen

Ji Zhao

Jock F Tomlinson

Ling Wang

Bai Yen Nguyen

Giap H Tran

Brad Sharpe-Geisler

Jayson Giai Trinh

Antony Davies

Mark Becker

In one embodiment of the invention, a programmable integrated circuit includes a plurality of SERDES circuits; a plurality of input/output (I/O) circuits; and a routing structure configurable to provide one or more of the following connections over routing paths having deterministic routing delays: coupling a SERDES circuit to another SERDES circuit; coupling a SERDES circuit to an I/O circuit; coupling an I/O circuit to a SERDES circuit; and coupling an I/O circuit to another I/O circuit.

SERDES with programmable I/O architecture

In one embodiment, a programmable interconnect includes SERDES circuits dedicated to communicating high-speed data and input/output (I/O) circuits dedicated to communicating low-speed data. A routing structure is configurable to couple a SERDES circuit to another SERDES circuit, a SERDES circuit to an I/O circuit, an I/O circuit to a SERDES circuit, and an I/O circuit to another I/O circuit over routing paths having deterministic routing delays. In another embodiment, the routing structure includes a high-speed routing structure for communicating high-speed data to and from a SERDES circuit and a low-speed routing structure for communicating low-speed data to and from an I/O circuit.

Systems and methods are disclosed to provide programmable input/output functionality for a programmable logic device. For example, in accordance with one embodiment of the present invention, a programmable interface selectively employs a scalable serializer-deserializer and clock and data recovery circuit. The programmable interface further includes programmable input/output buffers and embedded memory to allow the programmable logic device to support a wide range of input/output interface standards.

Scalable serializer-deserializer architecture and programmable interface

In a CDR (clock data recovery) deserializer, a clock divider receives a recovered clock signal (SCLK) and generates a divided clock signal (RPCLK). The frequency of the divided clock signal is lowered with each cycle of the divided clock signal being generated for each count of cycles of the recovered clock signal up to a predetermined ratio number. A serial-to-parallel shift register shifts in recovered serial data bits with each cycle of the recovered clock signal and outputs the predetermined ratio number of the shifted recovered serial data bits at a predetermined transition of every cycle of the divided clock signal. A SYNC (synchronization) detect logic asserts a VRS (diVider ReSet) signal coupled to the clock divider for controlling the clock divider to generate the predetermined transition for a cycle of the divided clock signal when the VRS signal is asserted. The SYNC detect logic includes a plurality of reloadable register portions for storing a plurality of synchronization bit patterns for a plurality of communications protocol. Each of a plurality of bit pattern comparators inputs an intermediate parallel data output (IPDO) from the shift register with each cycle of the recovered clock signal and compares for every cycle of the recovered clock signal the shifted recovered serial data bits to each of the synchronization bit patterns. A multiplexer selects one of the outputs of the bit pattern comparators as the VRS signal depending on the communications protocol of the recovered serial data bits.

Clock data recovery deserializer with programmable SYNC detect logic

In a digital filter of a DPLL (digital phase locked loop) for minimizing the bit error rate for multiple communications protocols, a first reloadable register portion stores a TBW (total bandwidth) value programmed into the first reloadable register portion through a first port, and a second reloadable register portion stores a DBW (differential bandwidth) value programmed into the second reloadable register portion through a second port. An upcounter generates an UPCNT value by counting up each UP signal pulse generated by a phase transition detector when a first phase of a SDIN (serial data input) signal leads a second phase of a current ACLK (recovered clock) signal. A downcounter generates a DOWNCNT value by counting up each DOWN signal pulse generated by the phase transition detector when the first phase of the SDIN (serial data input) signal lags the second phase of the current ACLK (recovered clock) signal. One of a FWD (forward) signal or a BWD (backward) signal are asserted or are both not asserted depending on the UPCNT value and the DNCNT value in comparison to the TBW value and the DBW value. Another clock signal having a leading phase from the current ACLK signal is selected as a new ACLK (recovered clock) signal when the FWD signal is asserted. Or, another clock signal having a lagging phase from the current ACLK signal is selected as the new ACLK (recovered clock) signal when the BWD signal is asserted. Or, the current ACLK signal remains as the new ACLK (recovered clock) signal if neither the FWD signal nor the BWD signal is asserted.

Digital phase locked loop with programmable digital filter

A programmable semiconductor device comprising a plurality of I/O circuits arranged into blocks includes a routing structure for each block, wherein each routing structure may programmably route signals between its block's I/O circuits and the I/O circuits within the remaining blocks. Each I/O circuit associates with a pin such that each block has a set of pins. A SERDES and a FIFO buffer associate with each block. Each block's SERDES couples between the block's I/O circuits and the block's set of pins. Each FIFO buffer couples between the SERDES and its block's I/O circuits.

High speed interface for a programmable interconnect circuit

A programmable interconnect circuit includes a phase-locked loop configured to provide an internal clock signal to I/O cells in the programmable interconnect circuit such that registers in the I/O cells may all be clocked in phase. In addition, the phase-locked loop may provide an external clock signal to the programmable interconnect circuit's routing structure such that external devices may clocked in phase with the external clock signal.

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San Jose, CA, United States of America

Kuang Chi