4 0 obj The DDR command bus consists of several signals that control the operation of the DDR interface. . /Parent 7 0 R There are no re strictions on how thes e signals are received, 22 0 obj <> endstream /Type /Page This interface between the PHY and memory is specified in the JEDEC standard. 21. So how are these commands issued? %%EOF For questions or comments on this article, please use the following link. When writing to a DRAM an important timing parameter that cannot be violated is tDQSS. tqX)I)B>== 9. /Parent 6 0 R 16 0 obj In most DDR generations since its inception, the timing relationship between the strobe and data signals is different for reads and writes (see Figure 3). In a device such as a network switch or router, there could be changes in Voltage and Temperature during its course of operation. /CropBox [0 0 612 792] 256x8 Bits OTP (One-Time Programmable) IP, TSMC 40G 0.9/1.8V Process, Dual Channel Digital Capacitive Sensor Interface, eMemory's Security-enhanced OTP Qualifies on TSMC N5 Process and Continues to Tackle Automotive Solutions, Cadence Demonstrates Interoperability with SK hynix's Highest Speed LPDDR5T Mobile DRAM at 9600Mbps, Arm could be on the hook for $8.5bn of Softbank debt, Applications And Operations of Video Analytics, Safeguarding the Arm Ecosystem with PSA Certified PUF-based Crypto Coprocessor, Mastering Key Technologies to Realize the Dream - M31 IP Integration Services, UFS 4.0 Explained: How the Latest Flash Storage Standard Propels Our 5G World, PCIe 6.0 - All you need to know about PCI Express Gen6, Update: GigOptix, Inc. /Kids [33 0 R 34 0 R 35 0 R 36 0 R 37 0 R 38 0 R 39 0 R 40 0 R 41 0 R 42 0 R] /MediaBox [0 0 612 792] /MediaBox [0 0 612 792] DDR Training. Functional DescriptionUniPHY 2. Features of the SDRAM Controller Subsystem, 4.2. In write-leveling mode, when the DRAM sees a DataStrobe (DQS), it uses it to sample the Clock (CK) and return the sampled value back to the controller through the DQ bus. Remember, the DQ pin is bidirectional. >> /Contents [112 0 R 113 0 R] // Performance varies by use, configuration and other factors. /Parent 9 0 R The RDA command tells the DRAM to automatically, The second write operation does not need an, Also note that the first command is a plain, The DRAM memory itself, which comprises of everything described above. << /MediaBox [0 0 612 792] /MediaBox [0 0 612 792] xb```f``e`202 +P#AQA%Ci^\% _s20h/XO@esM S AY>M}o6MYnSbQw[)&:y%_tbtRbf0;LJ$+yBD62_U.$z,vls:bx3YSaF-p`D@ digTe76,_7^#`~_Pt2Ic7#C$]xQ\9|^DZfU+`)]/{">V>H]-:::0A D8# 20p@FDBP0.Ae(QPP%n2rq(F%%W0CRL&4BCC2`:CYJ$]e@T.0S#7]RZ 9-U` ` r The DDR PHY Interface (DFI) is used in several consumer electronics devices including smart phones. Now, apart from the 4 file cabinet sizes -- if you consider each cabinet, say, the 4Gb medium size cabinet, it is offered in 3 form factors based on the size of paper it can hold. << << /Rotate 90 <>>> /Rotate 90 endobj 0000001667 00000 n endobj User Notification of ECC Errors, 4.10.1. 20 0 obj >> Because data can flow both from the controller to the DRAM (write operation) and from the DRAM to the controller (read operation, these digital lines are bi-directional in nature. /MediaBox [0 0 612 792] 20 0 obj endobj Figure 1: DDR4 Top Level Bank Group, Bank, Row, Column The top-level picture shows what a DRAM looks like on the outside. << 186 12 /Type /Page <> The protocol defines the signals, timing, and functionality required for efficient communication across the interface. x}[O@70["v{3Fc&>*Rm,;- -_w,t`>8C@JkA(^Zq`{Uh-8q8 s@IFH4P:JzlTn9 Determining the Failing Calibration Stage for a Cyclone V or Arria V HPS SDRAM Controller, 13.6.4. >> Figure 1: A representative test setup for physical-layer DDR testing. David Maliniak joined Teledyne LeCroy in 2012 after more than 30 years as a writer/editor in the electronics B2B press, most of which was spent at Electronic Design covering EDA and T&M. /Parent 6 0 R Standard DDR is designed for use in servers, cloud computing, networking, laptop, desktop, and consumer applications. The figure below zooms into one 240 leg of the DQ circuit and shows 5 p-channel devices connected to the poly-resistor. /MediaBox [0 0 612 792] The controller is responsible for initialization, data movement, conversion and bandwidth management. Demo Videos. 63 0 obj Freescale and the Freescale logo are trademarks TM . << We use cookies to provide you with a better experience. /Contents [85 0 R 86 0 R] /CropBox [0 0 612 792] endobj /CropBox [0 0 612 792] The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". /Contents [148 0 R 149 0 R] Necessary cookies are absolutely essential for the website to function properly. /Parent 8 0 R /CropBox [0 0 612 792] hwTTwz0z.0. /Parent 8 0 R uuid:af0d40d4-6f44-418e-88c9-31ea0885e9d9 Announces Acquisition of ChipX, Distributed Video Coding (DVC): Challenges in Implementation and Practical Usage, Beyond DDR2 400: Physical Implementation Challenges in Your SoC Design, Implementation basics for autonomous driving vehicles, An 800 Mpixels/s, ~260 LUTs Implementation of the QOI Lossless Image Compression Algorithm and its Improvement through Hilbert Scanning, Easing PCIe 6.0 Integration from Design to Implementation, Fmax Margin/Value Improvement for Memory Block During ECO Stage, Interlaken: the ideal high-speed chip-to-chip interface, System Verilog Macro: A Powerful Feature for Design Verification Projects, Dynamic Memory Allocation and Fragmentation in C and C++, Design Rule Checks (DRC) - A Practical View for 28nm Technology. /Resources 126 0 R /Type /Page /Parent 6 0 R /CropBox [0 0 612 792] /CropBox [0 0 612 792] /Type /Page /Rotate 90 The physical address is made up of the following fields: these individual fields are then used to identify the exact location in the memory to read-from or write-to. /Count 10 Since the Clock to Data/DataStrobe skew is different for each DRAM on the DIMM, the memory controller needs to train itself so that it can compensate for this skew and maintain tDQSS at the input of each DRAM on the DIMM. To READ from memory you provide an address and to WRITE to it you additionally provide data. /MediaBox [0 0 612 792] When you READ an address from a DDR4 DRAM the data is returned as a burst of 8 (typically called the Burst Length 8 or BL8 mode). /ModDate (D:20090708193957-07'00') /Resources 147 0 R A good place to start is to look at some of the essential IOs and understand what their functions are. /Contents [184 0 R 185 0 R] << /Type /Page Efficiency Monitor and Protocol Checker, 1.7.1.1. The Lattice Double Data Rate (DDR3) Physical Interface (PHY) IP is a general-purpose IP that provides connectivity between a DDR3 memory Controller (MC) and the DDR3 memory devices compliant with JESD79-3 specification. It requires every engineer working on SoC to be well versed with DDR protocol concepts including DDR addressing, DDR memory organization, DDR wrapper, DDR controller and DDR PHY. endobj 2 DRAM Main Memory Main memory is stored in DRAM cells that have much higher storage density DRAM cells lose their state over time -must be refreshed periodically, hence the name Dynamic endobj The industry is beginning to embrace new low-power and DDR memory technologies, including high-performance devices such as servers, storage, and networking; autonomous vehicles; and low-power handheld devices and IoT, stated John MacLaren, DFI Group chairman and Cadence design engineering architect. It is true that DDR1 and DDR2 RAM are no longer in use, and in fact, DDR1 memory is long gone. /MediaBox [0 0 612 792] /Rotate 90 >> HPC II Memory Interface Architecture, 5.2. >> << DFI is an interface protocol that defines signals, timing, and programmable parameters required to transfer control information and data to and from the DRAM devices, and between MC (Micro Controller) and PHY. /Type /Page /Rotate 90 endobj , DDR4 SDRAM - Initialization, Training and Calibration, CWL is the time delay between the column address and data at the inputs of a DRAM, Read/Write Training (a.k.a Memory Training or Initial Calibration), Runs algorithms to align clock [CK] and data strobe [DQS] at the DRAM, Runs algorithms and figures out the correct read and write delays to the DRAM, Reports errors if the signal integrity is bad and data cannot be written or read reliably. Creating a Top-Level File and Adding Constraints, 4.14.1. /Rotate 90 stream /Contents [193 0 R 194 0 R] If you're itching for more details, read on. /CropBox [0 0 612 792] /MediaBox [0 0 612 792] Stage 2: Write Calibration Part One, 1.17.6. endobj DDR4 DRAMs contain four 8-bit programmable registers called MPR registers that are used for DQ bit training (i.e., Read and Write Centering). /MediaBox [0 0 612 792] This is called the DRAM sub-system and it's made up of 3 components: There's a lot going on in the picture above, so lets break it down: Think of the controller as the brains and the PHY as the brawns. The strobe is essentially a data valid flag. /Parent 3 0 R sfo1411577352050. %PDF-1.5 MOSYS FCRAM VCDRAM $ Modifications Targeting Latency Targeting Throughput Targeting Throughput cWpn! 18 0 obj It is typically a step that is performed before Read Centering and Write Centering. You must Register or /Kids [6 0 R 7 0 R 8 0 R 9 0 R 10 0 R 11 0 R] /Resources 183 0 R DDR4 basics - Free download as PDF File (.pdf), Text File (.txt) or read online for free. The above explanation is a quick overview of ZQ calibration. >> /CropBox [0 0 612 792] Ck!@VY@0GT,iY Gc7ie8NrIucYB6(%,L\G Available as a product optimized solution for specific applications such as DDR5, DDR4, DDR3 with many configuration options to select desired features and . /Rotate 90 /Type /Page endobj endobj endobj endobj /Resources 120 0 R The specification, available for download at DDR is being developed by expert contributors from recognized leaders in the semiconductor, IP and electronic design automation (EDA) industries, including: ARM, Denali, Intel, Rambus,Samsung, and Synopsys. 41 0 obj endobj Multiple Data Byte macro-cell blocks, each with 8 DQ buses (the least Data Byte block is one) and their respective DQS and DM signals. << This cookie is set by GDPR Cookie Consent plugin. SDRAM Controller Subsystem Programming Model, 4.14. /MediaBox [0 0 612 792] 2. This indicates the number of data pins (DQ) on the DRAM. /Type /Page AFI Tracking Management Signals, 1.15.1. Not open for further replies. >> The DRAM is soldered down on the board. In this article we explore the basics. /Parent 9 0 R /Parent 8 0 R /Nums [0 12 0 R] /Type /Catalog This puts the DRAM into write-leveling mode. This important phase is called Read/Write Training (or Memory Training or Initial Calibration) wherein the controller (or PHY) Runs algorithms to align clock [CK] and data strobe [DQS] at the DRAM /Contents [229 0 R 230 0 R] >> By clicking Accept All, you consent to the use of ALL the cookies. >> 0000005476 00000 n Whats All This About Unbounded Jitter, Anyway? /Type /Page 8 0 obj The DDR PHY implements the following functions: Did you find the information on this page useful? Depending on the size of the DRAM the number of ROW and COLUMN bits change. /Parent 8 0 R >> Command signals are clocked only on the rising edge of the clock. << At this point the controller locks the DQS delay setting and write-leveling is achieved for this DRAM device. . /Resources 90 0 R 0000001386 00000 n /Parent 3 0 R 29 0 obj 36 0 obj . R > > > 0000005476 00000 n Whats All this About Unbounded Jitter, Anyway this... An address and to WRITE to it you ddr phy basics provide data 90 endobj 0000001667 n. 1: a representative test setup for physical-layer DDR testing 112 0 R ] // Performance varies by use and., configuration and other factors > > /CropBox [ 0 0 612 792 ] hwTTwz0z.0: a test. Comments on this article, please use the following link course of operation Modifications Targeting Latency Targeting Throughput Targeting Targeting. Of operation long gone fact, DDR1 memory is long gone stream /Contents [ 184 R! 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