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Posts Tagged ‘FPGA’

Understanding the inner workings of UVM – Part 2

Monday, January 29th, 2018

In this blog, my major focus is on explaining the concepts such as Sequence, Sequencer, Driver and showing how the communication takes place from sequence to sequencer and from sequencer to driver. In the previous blog, I included a top-level diagram of the UVM structure, showing different base classes. If you need refresh your memory on where the classes Sequence, Sequencer and Drivers stand please click–understanding-the-inner-workings-of-uvm.

So, let’s look at the main concepts and follow the communication mechanism they use for the effective execution of a test.

How to Design the New Generation of Reprogrammable Router/Switch Using Zynq FPGA

Thursday, January 25th, 2018

A high-performance router is an absolute must if you want to run a high-traffic network in which different devices need to transfer and receive data as fast as possible. A router with a powerful processor and sufficient local memory reduces data hiccups and minimizes message loading and buffering times. But is that enough?

Because of the huge amount of data that people now generate – combined with the wealth of communication protocols, such as Wi-Fi, Ethernet, USB, SFP, QSFP – high-performance, hardware re-programmable routers are becoming popular. That hardware re-programmability is being delivered through FPGAs, and utilizing one as the main ‘processor’ on the router makes it easy to add or modify desired modules such as encryption and compression.


Partition your Design for FPGA Prototyping

Monday, December 11th, 2017

Modern ASIC and SoC designs have increased in complexity such that multiple FPGAs of the largest capacity are now required to prototype the entire functionality of the design. As design sizes increase, more and more FPGAs are required. The capacity and pin limitations of FPGAs create constraints for how the ASIC/SoC design can be mapped into the FPGAs. Aldec’s HES-DVM’s prototyping mode accounts for the limitations of the target FPGAs and allows the user to map a design to the FPGAs within these constraints.

Partitioning a design to fit into multiple FPGAs can be a lot of work

Designing the partitions with HES-DVM is as easy as selecting specific VHDL/SystemVerilog design modules from the hierarchy and moving them to a desired partition. All information about the design modules and the amount of LUTs, Flip-flops, memory blocks, DSP slices, and I/O consumed are displayed for convenience. These values can also be viewed as a percentage of the target FPGAs’ available resources allowing you to know when an FPGA is full.

Adding a module to a partition

Mapping a partition to an FPGA

Once the partitions are finalized, each partition can be assigned to a specific FPGA. A design successfully fitting into the FPGAs on the target prototyping board is only the beginning. There still remains a big problem with the sheer number of connections between the partitions. Modern designs have thousands of internal signals interconnecting major blocks or sub-systems. It’s likely that there won’t be a sufficient amount of direct connections between FPGAs to support the design’s internal wiring. How can the large amount of internal design signals possibly be accommodated by the relatively smaller amount of I/O available from the FPGAs?

For the rest of this article, visit the Aldec Design and Verification Blog.

Emulation in FPGA

Wednesday, November 22nd, 2017

For many years, emulators were available only to verification teams working on the largest projects in companies with deep enough pockets. Due to size rather than capabilities they were called “Big Box” emulators and typically were used in order to recover some of the time lost on RTL simulation. Meanwhile, FPGA technology has been available long enough to mature to the point where FPGA based emulation became available – and I’m not talking here about FPGA prototyping.

“Emulation – Prototyping, aren’t they just synonyms?”

Sure, they are not. The most significant differences between FPGA usage in prototypes and in emulation are shown in table 1.




Clock frequency

10-200 MHz

1-20 MHz

Clock Topology

Multiple asynchronous sources – limited number of domains

Derived from emulation core clock – unlimited number of domains

Speed Limitation

Determined by Inter-FPGA signal multiplexing

Determined by FPGA-to-Host Comms, Inter-FPGA signal multiplexing

Stimulus Source

In-System, Real-world IO

Connection with simulators, virtual platforms, virtual models and other testbenches

Signal Capture

Selected Nodes

Full Visibility

Memory Models

Near-match to physical


Design Setup

Computer aided but with extensive user’s input and decisions

Fully automated

Table 1: Typical differences between FPGA usage in prototyping and emulation

FPGAs are the fastest platform for prototyping, but we can also harness that speed into our verification environment, then we can achieve runtime performance 2x to 5x faster than traditional “big box” emulation systems, and all at a fraction of the cost per gate per MHz.

“FPGAs are way too small for our SoC design, aren’t they?”

In the HES-US-2640 board, Aldec already has the largest capacity single FPGA boards commercially available today. Connecting 4 such boards in a backplane gives you 24 largest Xilinx UltraScale chips in which you can implement 633 Million ASIC Gates and still have 40% of capacity margin to facilitate FPGA Place & Route.

Figure 1: Scalable HES platform for prototyping & emulation

Not all designs need such excessive capacity, especially IoT projects, where the primary requirement is small footprint and energy-safe design. You will find the proper configuration in Aldec HES boards versatile portfolio containing Virtex-7, Virtex UltraScale and Kintex UltraScale based hardware.


For the rest of this article, visit the Aldec Design and Verification Blog.

Zynq-based Embedded Development Kit for University Programs

Tuesday, October 17th, 2017

Creativity and innovation, which lead the society to success, rest on the foundational institutions such as schools and universities. They provide fertile soil to seed, grow and flourish enterprises. To harvest more within an industry, the ecosystem needs to be enriched where the seeds are grown. Considering that the university’s courses are the nutrition to student, they need to be designed in a productive manner as they will provide the next generation of engineers. By providing the necessary platform in addition to the rich and informative tutorials, the quality of the input information for students would be assured. Particularly in the field of Electrical and Computer Engineering, it is important that students get as much hands on experience as possible, and tackle design challenges – such as HW/SW co-design and co-verification – before entering the job market; for their own benefit as well as the industry as a whole.

In this blog, you will become familiar with the TySOM Education kit (TySOM EDU) package designed for the university courses related to hardware design and embedded system design researches.

The TySOM EDU contains a TySOM embedded development board, Riviera-PRO advanced hardware simulator and informative tutorials and reference designs. Although it is possible to choose any development board from the TySOM embedded development board family, the TySOM-1A-7Z010 would be the most cost-effective solution for most university projects.

TySOM-1A-7Z010 (ZynqTM) is a ready-to-use and feature-rich embedded development board which provides the required peripherals to tackle both basic and advanced Zynq-based projects. The XC7Z010 is based on the Xilinx® All Programmable System-on-Chip (SoC) architecture, which integrates a dual-core ARM Cortex-A9 processor with Xilinx 7-series Field Programmable Gate Array (FPGA) logic. Coupling the device to a rich set of peripherals for connectivity, communication and multimedia, makes this board ideal for university projects requiring HW/SW co-design.  For the rest of this article, visit the Aldec Design and Verification Blog.

Synthesis of Energy-Efficient FSMs Implemented in PLD Circuits

Tuesday, September 26th, 2017

Well, summer has been and gone; and for most of us it was a time to relax and reflect on our working practices. What can we do to achieve better results? And what can we do to break out of the routine of working on so many revisions?

For me, one of my summer break ponderings was thinking back on a trick I learned while working with my colleagues at the Silesian University of Technology.

CMOS technology is the one that has dominated all applications of digital circuits. Power consumed by a CMOS digital circuit is the sum of two components: static power and dynamic power. The static power is a characteristic feature of the technology process used, and is associated with leakage currents in steady state. The dynamic power consumed by a CMOS gate is proportional to average switching activity at the output of the gate, which describes how often the state at the gate output is changing. The dynamic power component can thus be considered and minimized in the appropriate process of logic synthesis.

The essence of logic synthesis oriented toward energy-efficiency requires finding a circuit structure in which the number of state transitions is minimized.

Switching global clock networks are responsible for a significant part of the total power dissipated by a CMOS VLSI circuit. That’s why many engineers try to block the clock signal to achieve power reductions in synchronous circuits.

Programmable Logic Devices (PLDs), and especially Field Programmable Gate Arrays (FPGAs), constitute a relatively new and rapidly developing branch of digital electronics. Constantly growing logic capacities at moderate prices make PLDs an attractive platform for not only prototyping but also short- and medium-volume production.

It is not always obvious though how best to map logic structures (resources) within a given PLD architecture when designing with energy-efficiency in mind. In particular, implementing clock gating is difficult, as PLD circuits contain dedicated clock networks, which do not contain any gating elements. “Disabling” the clock signal in PLD structures can be accomplished in two ways: firstly, by utilizing the “Enable Clock” inputs of memory elements or, secondly, by distributing the clock signal using local clock lines or general-purpose routing resources (which enable the insertion of logic gates). For the rest of this article, visit the Aldec Design and Verification Blog.


Don’t be a Slave to the Documentation

Wednesday, September 20th, 2017

Are you a requirements engineer but your main goal is to provide well organized documentation? Do you have a great knowledge about the industry, business analysis and systems but you are struggling with the shape and look of your documentation? Do you still hear, for instance, that the specification document is not easy to read and difficult to use?


Requirements first

Requirements are the starting point of all other activities in a project lifecycle. So the specification document is crucial for the project. The document has many audiences such us stakeholders, designers, verification engineers and other groups involved in the project. This forces the author of the document to take care of the structure and organization of the document. It is not a big deal to prepare such a document. The problem is that the document has to be modified many times. The requirements are constantly changing, with new features appearing, some being modified and some being removed. Reclassification and reorganization must be repeated many times. In which case, I am pretty sure you will be contending with issues such as auto numbering, indentation, paragraph styles as well as tables and drawings that just do not fit the page.

Another kind of trouble comes from collaboration. Requirements should be developed by more than one engineer but working together on the same document is really a challenge. Forgetting to enable Track Changes, using the wrong version of a document or even using different version of Office tools are the most common collaboration issues.

Finally, there may be a situation in which you focus on a document’s structure and aesthetics more than its content. In the end your document may be well prepared but there is a serious risk that the requirements will be ambiguous, incomplete and/or inconsistent. This can happen when huge amounts of energy are spent solely on keeping the document organized and current. For the rest of this article, visit the Aldec Design and Verification Blog.

Demystifying AXI Interconnection for Zynq SoC FPGA

Thursday, September 14th, 2017

Imagine traveling back in the time to the early human ages. It’s going to be both scary and interesting when you meet a person who probably cannot speak or if they do you won’t be able to understand them. Clearly, communication will not be possible until you find a mutual way to convey your respective meanings/intentions. The same principle applies in the world of electronics as there are various types of interfaces among electronic devices. Therefore, a standard communication protocol eases the transformation of data in a system, especially in a System-on-Chip (SoC) system which consists of different systems.

SoC FPGAs such as Xilinx® Zynq™ establishes the ARM Advanced Microcontroller Bus Architecture (AMBA) as the on-chip interconnection standard to connect and manage the functional blocks within the SoC design. The Advanced eXtensible Interface (AXI) is designed for FPGAs based on AMBA as a protocol for communication between blocks of IP.


Introduction to Zynq™ Architecture

Friday, August 25th, 2017

The history of System-on-Chip (SoC)

Do we prefer to have a small electronic device or a larger one? The answer will often be “the smaller one”. However, before the commercialization of small radios, many people were interested in having big radios for the extravagance. Subsequently, at the beginning of the emergence of compact radios, those who preferred the flamboyance of large radios refused using compact radios. Slowly, but surely, the overwhelming benefits of owning a more compact radio led to the proliferation of smaller devices. These days the progression of the technology enables cutting-edge companies to encapsulate different parts of a system into increasingly smaller devices, all the way down to a single chip, which added the System-on-Chip (SoC) concept to the electronics world. By way of an example of a SoC, I will explain the Zynq-7000 all-programmable SoC. It consists of two hard processors, programmable logic (PL), ADC blocks and many other features all in one silicon chip.

Before the invention of the Zynq, processors were coupled with a Field Programmable Gate Array (FPGA) which made communication between the Programmable Logic (PL) and Processing System (PS) complicated. The Zynq architecture, as the latest generation of Xilix’s all-programmable System-on-Chip (SoC) families, combines a dual-core ARM Cortex-A9 with a traditional (FPGA). The interface between the different elements within the Zynq architecture is based on the Advanced eXtensible Interface (AXI) standard, which provides for high bandwidth and low latency connections.

Before implementing the ARM processor inside the Zynq device, users were using a soft core processor such as Xilinx’s Microblaze. The main advantage of using Microblaze was, and remains, the flexibility of the processor instances within a design. On the other hand, the inclusion of hard processor in Zynq delivers significant performance improvements. Also, by simplifying the system to a single chip, the overall cost and physical size of the device are reduced.

Zynq Design Flow

The design flow for the Zynq architecture has some steps in common with a regular FPGA. The first stage is to define the specifications and requirements of the system. Next, during the system design stage, the different tasks (functions) are assigned to implementation in either PL or PS which is called task partitioning. This stage is important because the performance of the overall system will depend on tasks/functions being assigned for implementation in the most appropriate technology: hardware or software. For the rest of this article, visit the Aldec Design and Verification Blog.

Accelerating Simulation of Vivado Designs with HES

Friday, August 11th, 2017

FPGA Design Verification Challenge

The FPGA design and verification “ecosystem” changes rapidly to keep pace with the fast growing size of FPGA devices. The largest Xilinx Virtex UltraSCALE chips provide 4.4 Million logic cells or using another metric 50 million equivalent gate count.

To enable efficient design process for Virtex-7 and newer UltraSCALE FPGAs, Xilinx provides software called Vivado Design Suite. Besides supporting a classical HDL design flow, it also provides system level design tools like IP Integrator, System Generator or even High Level Synthesis, that are very convenient for designing large and complex designs.

Verification has always taken a significant share of the project schedule with HDL simulation being the main stage of that process. With such big designs however, even the fastest simulators would spend hours in simulation tasks.

Simulation Acceleration with HES-DVM™

Aldec’s HES-DVM bridges this gap enabling accelerated simulation with the design running in the FPGA and the testbench in the simulator.

Aldec has been providing HES™ – Hardware Emulation Solutions since 2001. During that time the HES evolved to address the most sophisticated design requirements and fulfill customers’ requirements. Thus, simulation acceleration is only one example of how HES can be used with other applications being hybrid co-emulation, in circuit emulation, and physical prototyping.

With simulation acceleration the user can move any synthesizable module from simulator to the FPGA thus offload some processing from the HDL simulator. Typically, an entire design is implemented in HES board and the simulator only executes the testbench.

Figure 1: Signal-level simulation acceleration

The HES boards are seamlessly integrated with the simulator with PCI Express x8 physical connection to the host workstation. The HES-DVM provides co-simulation interfaces for Aldec’s Riviera-PRO and Active-HDL simulators but also for other 3rd party simulators. It can be used both in Linux and Windows operating systems with all required PCIe drivers and interfaces working out of the box.

The DVM tool automates the process of design compilation and implementation for HES boards. It generates all necessary scripts and configuration files to run simulation acceleration in a given HES board but also brings many useful debugging features. Despite running your design in FPGA hardware you can keep simulation level visibility with an RTL View of all internal probes.

Figure 2: Design setup flow for acceleration using DVM™

Acceleration Benchmark

MIG controller for DDR3, AXI interconnect, two AXI traffic generators and one AXI protocol checker as shown in the following diagram.How much acceleration can I achieve? This is always the first customer’s question and frankly there is no straight answer because the result depends on the complexity of both the design and the testbench. Usually a good estimation can be obtained from running simulation profiling and then applying Amdahl’s rule. However, the best way to verify acceleration potential is just to experiment with a typical design, so we have created a simple design of a memory sub-system using Xilinx Vivado Design environment. It contains MIG controller for DDR3, AXI interconnect, two AXI traffic generators and one AXI protocol checker as shown in the following diagram.

Figure 3: Diagram created for memory subsystem benchmarking

Benchmark Results

Workstation and software used for benchmarking:

CPU: Intel(R) Core(TM) i7-3770K CPU @ 3.50GHz
RAM: 32 GB
HES Board: HES7XV4000BP_REV2, contains 2x Virtex7 2000 FPGA

OS: Linux CentOS 6, x86_64
Simulator: Riviera-PRO 2017.02
Design env: Vivado 2016.4
Acceleration env: HES-DVM 2017.02

If you are interested in further details about this project, benchmark, and tools which can significantly accelerate your simulation you can view the following application note:

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