US20030128621A1 - Auto-disable receive control for ddr receive strobes - Google Patents
Auto-disable receive control for ddr receive strobes Download PDFInfo
- Publication number
- US20030128621A1 US20030128621A1 US10/114,408 US11440802A US2003128621A1 US 20030128621 A1 US20030128621 A1 US 20030128621A1 US 11440802 A US11440802 A US 11440802A US 2003128621 A1 US2003128621 A1 US 2003128621A1
- Authority
- US
- United States
- Prior art keywords
- latch
- receive
- gate
- data
- strobe
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C7/00—Arrangements for writing information into, or reading information out from, a digital store
- G11C7/10—Input/output [I/O] data interface arrangements, e.g. I/O data control circuits, I/O data buffers
- G11C7/1078—Data input circuits, e.g. write amplifiers, data input buffers, data input registers, data input level conversion circuits
- G11C7/109—Control signal input circuits
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C7/00—Arrangements for writing information into, or reading information out from, a digital store
- G11C7/10—Input/output [I/O] data interface arrangements, e.g. I/O data control circuits, I/O data buffers
- G11C7/1078—Data input circuits, e.g. write amplifiers, data input buffers, data input registers, data input level conversion circuits
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C7/00—Arrangements for writing information into, or reading information out from, a digital store
- G11C7/10—Input/output [I/O] data interface arrangements, e.g. I/O data control circuits, I/O data buffers
- G11C7/1078—Data input circuits, e.g. write amplifiers, data input buffers, data input registers, data input level conversion circuits
- G11C7/1087—Data input latches
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C2207/00—Indexing scheme relating to arrangements for writing information into, or reading information out from, a digital store
- G11C2207/10—Aspects relating to interfaces of memory device to external buses
- G11C2207/107—Serial-parallel conversion of data or prefetch
Definitions
- the present invention generally relates to computer systems. More specifically, the present invention relates to the control of a receive strobe in a computer circuit.
- Speed has always been an important factor in measuring the performance of a computer system, and speed depends, among other factors, how fast a central processing unit (CPU) can perform mathematical calculations, and how fast can data be retrieved from and stored into data registers.
- CPU central processing unit
- DDR-SDRAM Double-Data-Rate Synchronous Dynamic Random Access Memory
- SDRAM standard DRAM
- DDR Double-Data-Rate Synchronous Dynamic Random Access Memory
- DDR differs from standard DRAM (SDRAM) in that it uses a separate strobe signal by which some or all of its data timing is referenced, and both the rising and the falling edges of the strobe signal are used to clock data into its destination.
- SDRAM standard DRAM
- Using both edges of the strobe signal to transfer data thus doubles the amount of data transferred in a given time interval.
- This technique also allows higher data rates than standard single-data-rate SDRAM because the explicit strobe signal by which data is referenced can be used to remove some of the timing uncertainty present in the data receive path.
- the strobe is a bi-directional signal, which is driven along with the data, and can be driven by either a controller or the DDR. If the controller wants to store (write) a data into the DDR, the controller drives the strobe to indicate the availability of the data on the data bus. If the controller is retrieving (reading) data from the DDR, the DDR controls the strobe to indicate the data is available on the data bus. This implies that neither the controller nor the DDR drives the strobe during time intervals between reads and writes. This results in the strobe signal being in a high-impedance state, usually at an indeterminate logic level, when not driven by either the controller or the DDR. Since the edges of the strobe are used to clock in receive data during reads, the propagation of this indeterminate level is troublesome. At this indeterminate level, the strobe may lead to an unintended edge at the receiving end which will latch an unexpected data.
- the present invention discloses a circuit and method for using the last falling edge of a receive strobe to block further reception of additional signals from the receive strobe.
- a dedicated circuit that uses a phase signal, a receive enable strobe, a 2X clock signal, and a receive strobe from an I/O receiver to generate a new receive strobe for use by a data latch.
- the phase signal is a late clock signal
- the 2X clock signal is twice as fast as the system clock.
- the receive enable strobe is synchronous with the system clock.
- the circuit includes several latches and ensures the last latch is gated asynchronously from the receive strobe and is clocked at the falling edge of the receive strobe.
- the output of this last latch is ANDed with the receive strobe and generates the new strobe for the DDR-SDRAM. This ensures the new strobe remains at a logic level that is unknown instead of undetermined, thus eliminating the unwanted latching at the receiving end.
- the circuit according to the present invention changes the way the receive strobe is connected between a received data latch and the DDR-SDRAM.
- the receive strobe connection between the received data latch and the DDR-SDRAM is replaced by the circuit according to the present invention.
- the circuit receives the receive strobe from a bi-directional I/O buffer and generates a new receive strobe to a data latch delay system.
- the new receive strobe is used as a clock in the received data latch to clock the data from the DDR-SDRAM.
- the circuit according to the present invention can be integrated inside of an application specific integrated circuit (ASIC) or inside of the DDR-SDRAM.
- ASIC application specific integrated circuit
- DDR-SDRAM DDR-SDRAM
- FIG. 1 is a schematic diagram for one embodiment of the present invention.
- FIG. 2 is a timing diagram for one embodiment of the present invention.
- FIG. 3 is a schematic diagram of a read access circuit inside an ASIC employing an auto-disable circuit according to the present invention.
- FIG. 1 is a schematic diagram for one circuit 10 that generates a new strobe 12 , which remains in a known digital state while not in use, according to the present invention.
- the operation of the circuit 10 is controlled by a receive enable signal 14 that is synchronous to a common clock.
- a 2X clock 16 and a phase signal 18 are also used in this design. Note that all signals transmitted to the DDR-SDRAM, including its differential clock, also known as the phase signal, are also referenced to the 2X clock.
- Multiplex latch (A) 20 aligns the receive enable signal 14 with the 2X clock 16 .
- the output of this latch 20 is fed to multiplex latch (B) 22 and latch (E) 24 .
- the output of latch (B) 22 is fed to latch (C) 26 and to a NAND gate 28 .
- Latches (B), (C), and (D) are gated by 2X clock 16 .
- the output from the NAND gate 28 and the inverted output from latch (C) are fed to latch (D) 30 , which is clocked by 2X clock 16 .
- the inverted output from latch (D) 30 is a one-2X-clock-long pulse that asynchronously sets gate latch (F) 32 .
- the output of latch (A) 20 also is delayed at latch (E) 24 , and then applies to the data port of gate latch (F) 32 . Since gate latch (F) 32 is set asynchronously, subsequent strobe transitions are observable at the clock port on gate latch (F) 32 . Gate latch (F) 32 is then clocked at the falling edge of the receive strobe.
- FIG. 2 illustrates a timing diagram for the circuit in FIG. 1.
- the set pulse is the output from latch (D) 30 after the inverter.
- the circuit ensures the set pulse is generated after the receive strobe 34 is driven by DDR-SDRAM or a controller.
- the set pulse sets gate latch (F) 32 and the output of gate latch (F) 32 enables AND gate 36 to let the receive strobe to pass through. When this happens, the AND gate 36 is open.
- the AND gate is closed when the receive enable 14 is negated and propagates through latch (E) 24 and gated to gate latch (F) 32 by the last falling edge of the receive strobe 34 .
- the output of gate latch (F) 32 immediately feeds to the AND gate 36 , thus closing it. After the AND gate is closed, the new strobe 12 is immune from the state of the receive strobe 34 .
- FIG. 3 is an illustration of an ASIC 50 reading data from a DDR-SDRAM device 52 .
- the receive strobe (DDR strobe) 54 is received at the I/O receiver 56 .
- the DDR-SDRAM 52 puts data onto the data path 60 , and activates receive strobe 54 .
- the receive strobe 54 passes through the bi-directional I/O receiver 56 and feeds to an auto-disable circuit 62 .
- the auto-disable circuit 62 generates a new strobe signal 64 that feeds through a data latch delay system 66 , then to the received data latch 68 .
- the received data latch 68 uses this new strobe signal to clock the data.
- a similar circuit can be built into the DDR-SDRAM to ensure that DDR-SDRAM will not latch wrong data during a store operation.
- gate latch (F) 32 will remain high while being clocked.
- the controller or the DDR-SDRAM will negate the receive enable 14 at the appropriate time to ensure that the data port on gate latch (F) 32 goes low between the second-to-last and last falling edges of the strobe 34 .
- gate latch (F) 32 goes low, subsequently closing the AND gate 36 and rendering circuitry downstream insensitive to further transitions of the receive strobe 34 .
- the controller must assert its receive enable 14 such that gate latch (F) is asynchronously set after the receive strobe 34 is driven low by the DDR-SDRAM that is being read.
- the controller must deassert its receive enable 14 such that the data port to gate latch (F) 32 is deasserted after the second-to-last falling edge and before the last falling edge of the receive strobe 34 .
- the clock path to gate latch (F) 32 must be faster than the falling-edge-to-float time from the DDR-SDRAM that is being read.
Abstract
Description
- This invention claims priority to the provisional application, AUTO-DISABLE RECEIVE CONTROL FOR DDR RECEIVE STROBES, Serial No. 60/346,504, filed on Jan. 08, 2002.
- 1. Field of the Invention
- The present invention generally relates to computer systems. More specifically, the present invention relates to the control of a receive strobe in a computer circuit.
- 2. Description of the Related Art
- Speed has always been an important factor in measuring the performance of a computer system, and speed depends, among other factors, how fast a central processing unit (CPU) can perform mathematical calculations, and how fast can data be retrieved from and stored into data registers.
- Data are stored into the data registers or memory locations with help of a strobe signal. The data can be latched to their location by either the rising edge or the falling edge of a strobe signal. To achieve a high data rate, a Double-Data-Rate Synchronous Dynamic Random Access Memory (DDR-SDRAM or DDR) has been used. DDR differs from standard DRAM (SDRAM) in that it uses a separate strobe signal by which some or all of its data timing is referenced, and both the rising and the falling edges of the strobe signal are used to clock data into its destination. Using both edges of the strobe signal to transfer data thus doubles the amount of data transferred in a given time interval. This technique also allows higher data rates than standard single-data-rate SDRAM because the explicit strobe signal by which data is referenced can be used to remove some of the timing uncertainty present in the data receive path.
- The strobe is a bi-directional signal, which is driven along with the data, and can be driven by either a controller or the DDR. If the controller wants to store (write) a data into the DDR, the controller drives the strobe to indicate the availability of the data on the data bus. If the controller is retrieving (reading) data from the DDR, the DDR controls the strobe to indicate the data is available on the data bus. This implies that neither the controller nor the DDR drives the strobe during time intervals between reads and writes. This results in the strobe signal being in a high-impedance state, usually at an indeterminate logic level, when not driven by either the controller or the DDR. Since the edges of the strobe are used to clock in receive data during reads, the propagation of this indeterminate level is troublesome. At this indeterminate level, the strobe may lead to an unintended edge at the receiving end which will latch an unexpected data.
- Thus, a more precise system of blocking the reception of the strobe signal is needed at high clock speeds. It is to such a system and method that the present invention is primarily directed.
- The present invention discloses a circuit and method for using the last falling edge of a receive strobe to block further reception of additional signals from the receive strobe.
- According to one embodiment of the present invention a dedicated circuit that uses a phase signal, a receive enable strobe, a 2X clock signal, and a receive strobe from an I/O receiver to generate a new receive strobe for use by a data latch. The phase signal is a late clock signal, and the 2X clock signal is twice as fast as the system clock. The receive enable strobe is synchronous with the system clock.
- The circuit includes several latches and ensures the last latch is gated asynchronously from the receive strobe and is clocked at the falling edge of the receive strobe. The output of this last latch is ANDed with the receive strobe and generates the new strobe for the DDR-SDRAM. This ensures the new strobe remains at a logic level that is unknown instead of undetermined, thus eliminating the unwanted latching at the receiving end.
- The circuit according to the present invention changes the way the receive strobe is connected between a received data latch and the DDR-SDRAM. The receive strobe connection between the received data latch and the DDR-SDRAM is replaced by the circuit according to the present invention. The circuit receives the receive strobe from a bi-directional I/O buffer and generates a new receive strobe to a data latch delay system. The new receive strobe is used as a clock in the received data latch to clock the data from the DDR-SDRAM.
- The circuit according to the present invention can be integrated inside of an application specific integrated circuit (ASIC) or inside of the DDR-SDRAM.
- Other objects, features, and advantages of the present invention will become apparent after review of the hereinafter set forth Brief Description of the Drawings, Detailed Description of the Invention, and Claims appended herewith.
- FIG. 1 is a schematic diagram for one embodiment of the present invention.
- FIG. 2 is a timing diagram for one embodiment of the present invention.
- FIG. 3 is a schematic diagram of a read access circuit inside an ASIC employing an auto-disable circuit according to the present invention.
- Referring now in more detail to the drawings in which like numerals refer to like elements throughout the several figures, FIG. 1 is a schematic diagram for one
circuit 10 that generates anew strobe 12, which remains in a known digital state while not in use, according to the present invention. The operation of thecircuit 10 is controlled by a receive enablesignal 14 that is synchronous to a common clock. A2X clock 16 and aphase signal 18 are also used in this design. Note that all signals transmitted to the DDR-SDRAM, including its differential clock, also known as the phase signal, are also referenced to the 2X clock. - Multiplex latch (A)20 aligns the receive enable
signal 14 with the2X clock 16. The output of thislatch 20 is fed to multiplex latch (B) 22 and latch (E) 24. The output of latch (B) 22 is fed to latch (C) 26 and to aNAND gate 28. Latches (B), (C), and (D) are gated by2X clock 16. - The output from the
NAND gate 28 and the inverted output from latch (C) are fed to latch (D) 30, which is clocked by2X clock 16. The inverted output from latch (D) 30 is a one-2X-clock-long pulse that asynchronously sets gate latch (F) 32. The output of latch (A) 20 also is delayed at latch (E) 24, and then applies to the data port of gate latch (F) 32. Since gate latch (F) 32 is set asynchronously, subsequent strobe transitions are observable at the clock port on gate latch (F) 32. Gate latch (F) 32 is then clocked at the falling edge of the receive strobe. - FIG. 2 illustrates a timing diagram for the circuit in FIG. 1. The set pulse is the output from latch (D)30 after the inverter. The circuit ensures the set pulse is generated after the receive
strobe 34 is driven by DDR-SDRAM or a controller. The set pulse sets gate latch (F) 32 and the output of gate latch (F) 32 enables ANDgate 36 to let the receive strobe to pass through. When this happens, the ANDgate 36 is open. The AND gate is closed when the receive enable 14 is negated and propagates through latch (E) 24 and gated to gate latch (F) 32 by the last falling edge of the receivestrobe 34. The output of gate latch (F) 32 immediately feeds to theAND gate 36, thus closing it. After the AND gate is closed, thenew strobe 12 is immune from the state of thereceive strobe 34. - FIG. 3 is an illustration of an
ASIC 50 reading data from a DDR-SDRAM device 52. The receive strobe (DDR strobe) 54 is received at the I/O receiver 56. When the DDR-SDRAM 52 has retrieved a data requested by the controller 528, the DDR-SDRAM 52 puts data onto thedata path 60, and activates receivestrobe 54. The receivestrobe 54 passes through the bi-directional I/O receiver 56 and feeds to an auto-disablecircuit 62. The auto-disablecircuit 62 generates anew strobe signal 64 that feeds through a datalatch delay system 66, then to the receiveddata latch 68. The received data latch 68 uses this new strobe signal to clock the data. A similar circuit can be built into the DDR-SDRAM to ensure that DDR-SDRAM will not latch wrong data during a store operation. - In the embodiment disclosed by this invention, as long as receive enable
signal 14 from the synchronous controlling logic remains active, gate latch (F) 32 will remain high while being clocked. The controller or the DDR-SDRAM will negate the receive enable 14 at the appropriate time to ensure that the data port on gate latch (F) 32 goes low between the second-to-last and last falling edges of thestrobe 34. When the last falling edge of the receivestrobe 34 is received, gate latch (F) 32 goes low, subsequently closing the ANDgate 36 and rendering circuitry downstream insensitive to further transitions of the receivestrobe 34. - The controller must assert its receive enable14 such that gate latch (F) is asynchronously set after the receive
strobe 34 is driven low by the DDR-SDRAM that is being read. The controller must deassert its receive enable 14 such that the data port to gate latch (F) 32 is deasserted after the second-to-last falling edge and before the last falling edge of the receivestrobe 34. The clock path to gate latch (F) 32 must be faster than the falling-edge-to-float time from the DDR-SDRAM that is being read. - While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various other changes in form and detail may be made without departing from the spirit and scope of the invention.
Claims (8)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/114,408 US6597628B1 (en) | 2002-01-08 | 2002-04-02 | Auto-disable receive control for DDR receive strobes |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US34650402P | 2002-01-08 | 2002-01-08 | |
US10/114,408 US6597628B1 (en) | 2002-01-08 | 2002-04-02 | Auto-disable receive control for DDR receive strobes |
Publications (2)
Publication Number | Publication Date |
---|---|
US20030128621A1 true US20030128621A1 (en) | 2003-07-10 |
US6597628B1 US6597628B1 (en) | 2003-07-22 |
Family
ID=26812150
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/114,408 Expired - Lifetime US6597628B1 (en) | 2002-01-08 | 2002-04-02 | Auto-disable receive control for DDR receive strobes |
Country Status (1)
Country | Link |
---|---|
US (1) | US6597628B1 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7404116B2 (en) * | 2002-11-13 | 2008-07-22 | Etron Technology, Inc. | Semiconductor integrated circuit with full-speed data transition scheme for DDR SDRAM at internally doubled clock testing application |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100265610B1 (en) | 1997-12-31 | 2000-10-02 | 김영환 | Ddr sdram for increasing a data transmicssion velocity |
JP2000163965A (en) | 1998-11-27 | 2000-06-16 | Mitsubishi Electric Corp | Synchronous semiconductor storage |
US6081477A (en) | 1998-12-03 | 2000-06-27 | Micron Technology, Inc. | Write scheme for a double data rate SDRAM |
US6044032A (en) | 1998-12-03 | 2000-03-28 | Micron Technology, Inc. | Addressing scheme for a double data rate SDRAM |
JP2000187981A (en) * | 1998-12-22 | 2000-07-04 | Mitsubishi Electric Corp | Synchronous semiconductor memory |
JP3266127B2 (en) * | 1999-01-25 | 2002-03-18 | 日本電気株式会社 | Synchronous semiconductor memory device |
US6240042B1 (en) * | 1999-09-02 | 2001-05-29 | Micron Technology, Inc. | Output circuit for a double data rate dynamic random access memory, double data rate dynamic random access memory, method of clocking data out from a double data rate dynamic random access memory and method of providing a data strobe signal |
US6279073B1 (en) * | 1999-09-30 | 2001-08-21 | Silicon Graphics, Inc. | Configurable synchronizer for double data rate synchronous dynamic random access memory |
US6154419A (en) | 2000-03-13 | 2000-11-28 | Ati Technologies, Inc. | Method and apparatus for providing compatibility with synchronous dynamic random access memory (SDRAM) and double data rate (DDR) memory |
-
2002
- 2002-04-02 US US10/114,408 patent/US6597628B1/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
US6597628B1 (en) | 2003-07-22 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6930932B2 (en) | Data signal reception latch control using clock aligned relative to strobe signal | |
US6108795A (en) | Method for aligning clock and data signals received from a RAM | |
US6134182A (en) | Cycle independent data to echo clock tracking circuit | |
US7509469B2 (en) | Semiconductor memory asynchronous pipeline | |
US7594088B2 (en) | System and method for an asynchronous data buffer having buffer write and read pointers | |
US6633965B2 (en) | Memory controller with 1×/M× read capability | |
US6898648B2 (en) | Memory bus polarity indicator system and method for reducing the affects of simultaneous switching outputs (SSO) on memory bus timing | |
US6338127B1 (en) | Method and apparatus for resynchronizing a plurality of clock signals used to latch respective digital signals, and memory device using same | |
EP1642297B1 (en) | Data strobe synchronization circuit and method for double data rate, multi-bit writes | |
US20020147896A1 (en) | Memory controller with 1X/MX write capability | |
US7394721B1 (en) | Method and apparatus for data synchronization to local clock on memory reads | |
US20060028905A1 (en) | Method and apparatus for initialization of read latency tracking circuit in high-speed DRAM | |
US20020172079A1 (en) | Memory controller receiver circuitry with tri-state noise immunity | |
US7408394B2 (en) | Measure control delay and method having latching circuit integral with delay circuit | |
US6918016B1 (en) | Method and apparatus for preventing data corruption during a memory access command postamble | |
US6853594B1 (en) | Double data rate (DDR) data strobe receiver | |
JP2005523536A (en) | Method for performing access to a single port memory device, memory access device, integrated circuit device, and method of using an integrated circuit device | |
US6751717B2 (en) | Method and apparatus for clock synchronization between a system clock and a burst data clock | |
US6597628B1 (en) | Auto-disable receive control for DDR receive strobes | |
US11763865B1 (en) | Signal receiver with skew-tolerant strobe gating | |
US7990783B1 (en) | Postamble timing for DDR memories | |
US10496368B1 (en) | Systems and methods for memory FIFO control | |
US6356981B1 (en) | Method and apparatus for preserving data coherency in a double data rate SRAM | |
JPH025291A (en) | Semiconductor memory | |
JPS61190647A (en) | Data processor |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: 3DLABS, BERMUDA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KERL, DANIEL L.;REEL/FRAME:013209/0905 Effective date: 20020807 |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
FEPP | Fee payment procedure |
Free format text: PAT HOLDER NO LONGER CLAIMS SMALL ENTITY STATUS, ENTITY STATUS SET TO UNDISCOUNTED (ORIGINAL EVENT CODE: STOL); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
FPAY | Fee payment |
Year of fee payment: 4 |
|
FPAY | Fee payment |
Year of fee payment: 8 |
|
AS | Assignment |
Owner name: 3DLABS INC., LTD., BERMUDA Free format text: CORRECTIVE ASSIGNMENT TO CORRECT THE COVERSHEET'S RECEIVING PARTY DATA (ASSIGNEE'S NAME CORRECTED TO 3DLABS INC., LTD.) AS PREVIOUSLY RECORDED ON REEL 013209 FRAME 0905. ASSIGNOR(S) HEREBY CONFIRMS THE ASSIGNMENT;ASSIGNOR:KERL, DANIEL L.;REEL/FRAME:030488/0444 Effective date: 20020807 |
|
AS | Assignment |
Owner name: ZIILABS INC., LTD., BERMUDA Free format text: CHANGE OF NAME;ASSIGNOR:3DLABS INC., LTD.;REEL/FRAME:032588/0125 Effective date: 20110106 |
|
FPAY | Fee payment |
Year of fee payment: 12 |
|
AS | Assignment |
Owner name: RPX CORPORATION, CALIFORNIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ZIILABS INC., LTD.;REEL/FRAME:044476/0678 Effective date: 20170809 |
|
AS | Assignment |
Owner name: RPX CORPORATION, CALIFORNIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ZIILABS INC., LTD.;REEL/FRAME:044442/0111 Effective date: 20170809 |
|
AS | Assignment |
Owner name: JEFFERIES FINANCE LLC, NEW YORK Free format text: SECURITY INTEREST;ASSIGNOR:RPX CORPORATION;REEL/FRAME:046486/0433 Effective date: 20180619 |
|
AS | Assignment |
Owner name: BARINGS FINANCE LLC, AS COLLATERAL AGENT, NORTH CAROLINA Free format text: PATENT SECURITY AGREEMENT;ASSIGNORS:RPX CLEARINGHOUSE LLC;RPX CORPORATION;REEL/FRAME:054198/0029 Effective date: 20201023 Owner name: BARINGS FINANCE LLC, AS COLLATERAL AGENT, NORTH CAROLINA Free format text: PATENT SECURITY AGREEMENT;ASSIGNORS:RPX CLEARINGHOUSE LLC;RPX CORPORATION;REEL/FRAME:054244/0566 Effective date: 20200823 |
|
AS | Assignment |
Owner name: RPX CORPORATION, CALIFORNIA Free format text: RELEASE BY SECURED PARTY;ASSIGNOR:JEFFERIES FINANCE LLC;REEL/FRAME:054486/0422 Effective date: 20201023 |