How must I write VHDL to make it synthesizable?

Because large parts of the language make no sense in a hardware context, synthesizable VHDL is a relatively small subset of VHDL. You must stick to this subset, and understand exactly how the synthesis tool you use interprets that code. For FPGA in particular you must also develop a good understanding of the structure of your chip, and know how your code must reflect the most efficient use of that structure. Fundamentally, never forget that you are designing a circuit, not writing a program. Forgetting this simply but important fact will only lead to pain later.

Can I use VHDL for the analog part of a design?

Yes and No. Yes, there is a VHDL Analogue and Mixed Signal language (VHDL-AMS), based on VHDL 93, which allows modeling of both analogue and digital in the same language. However the idea of analogue synthesis is still in its early days, so currently you wouldn't normally be able to go on and synthesize an analogue model written in VHDL-AMS. There's a VHDL-AMS website at www.eda.org/vhdl-ams.

What is the difference between VHDL and Verilog?

Fundamentally speaking, not a lot. You can produce robust designs and comprehensive test environments with both languages, for both ASIC and FPGA. However, the two languages approach the task from different directions; VHDL, intended as a specification language, is very exact in its nature and hence very verbose. Verilog, intended as a simulation language, it much closer to C in style, in that it is terse and elegant to write but requires much more care to avoid nasty bugs. VHDL doesn't let you get away with much; Verilog assumes that whatever you wrote was exactly what you intended to write. If you get a VHDL architecture to compile, it's probably going to approximate to the function you wanted. For Verilog, successful compilation merely indicates that the syntax rules were met, nothing more. VHDL has some features that make it good for system-level modeling, whereas Verilog is much better than VHDL at gate-level simulation.

Intel marks 40 years of the 4004 microprocessor

A 1971 breakthrough that changed the world

CHIPMAKER Intel today celebrates the 40th anniversary of the 4004, the world's first commercially available microprocessor.

To call Intel's 4004 just a microprocessor is to do the microelectronics world a great disservice. Not only was the Intel 4004 the first commercial microprocessor, shattering what people thought of computers, it signaled Intel's shift away from manufacturing memory and into what was going to become the industry that changed the world forever.

Back in 1969 when Japanese calculator outfit Nippon Calculating Machine Corporation asked Intel to design 12 chips for a business calculator called Busicom, Intel had already achieved some success with its memory business. Although Intel was far from being a market leader, the two 'Fairchildren', Robert Noyce and Gordon Moore were busy making money fabbing RAM chips, but not for much longer.

Back in 1969, Intel didn't have the luxury of saying no to business and Federico Faggin, Ted Hoff and Masatoshi Shima got to work on designing a processor for the relatively mundane business calculator. Later Hoff remarked that in the late 1960s it simply wasn't feasible to talk about personal computers.

Like the birth of many revolutionary pieces of engineering, the 4004 was designed by a bunch of engineers working into the night on the promise of creating something completely different.

While Faggin, who had also worked at Fairchild Semiconductor with Noyce and Moore, was busy designing the 4004 Hoff is widely credited with coming up with the architecture. Faggin built Hoff's architecture, with the legend saying that the first wafers came back to Intel's Santa Clara offices at 6PM just as everyone was clocking out for the day. Faggin pulled an all nighter in the lab to check whether the first baked 4004 actually worked, and at 3AM, overcome with exhaustion and satisfied that the radical 4004 did the job, he went home to tell his wife, "It works!".

Faggin was so proud of his design that he etched his initials, FF, on one side of the 4004's design. In later iterations of the 4004 the initials were moved, but just like an artist, Faggin signed his own work. And make no mistake, the 4004 processor is a work of art.

It might sound bashful, but Intel's 4004 wasn't particularly powerful, and the firm admitted, "The 4004 was not very powerful, it was primarily used to perform simple mathematical operations in a calculator called Busicom." However Noyce and Moore realised that it wasn't the 4004 itself that was important but its architecture.

In terms of complexity, Intel's 4004 had 2,300 MOS transistors and was fabricated on a 10,000nm process node on 60mm wafers. In a graphic illustration of Moore's law, processors from Intel and AMD today typically have hundreds of millions of transistors and are fabricated on the 32nm process node on 300mm wafers. But the numbers simply don't tell the whole story, the fact is that the 4004 was not just a new chip with a new micro-architecture, but it was a radical new way of thinking and building processors.

What Faggin, Hoff and Shima had created with the 4004 was the ability to commoditise computing by adding the micro in microprocessors. Prior to the 4004, general purpose computers were the hulking machines you saw in black-and-white films as room-sized equipment. Henry Ford brought the motorcar to the wider public through mass production, while Intel brought computing to the masses by miniaturising it.

Intel showed what would become perhaps the first known example of its shrewd business policies by offering Busicom, now a company in its own right, a reported $60,000 for the design and marketing rights for the 4004. Busicom agreed to the deal and, even though a year later the firm went bust, Intel was left with the ability to sell the 4004, which it did in 1971.

In what would become standard Intel behaviour, the firm courted developers for its 4004 processor. Even at that time, Intel knew that software held the key to its success, and it wasn't wrong.

Like Noyce and Moore, Faggin chose to form his own company in 1974 called Zilog. The firm is extremely successful in embedded CISC processors but is best known for producing chips that were found in the Sinclair ZX Spectrum. Faggin still heads up Zilog but his name will forever be associated with the creation of arguably the 20th century's most important innovation in electronics. Shima followed Faggin to Zilog in 1975 and worked on the Z80 and Z8000.

Hoff stayed on at Intel, becoming an Intel Fellow and more recently was awarded the National Medal of Technology and Innovation in 2009 by US President Barack Obama, a year before Faggin received the same award.

What Faggin, Hoff and Shima created wasn't just a microprocessor, it was a blueprint for others to follow and quite simply extended what was thought possible. Credit should be given to Noyce, Moore and Intel's third co-founder, Andy Grove, for letting the electronics engineers have the time and resources to develop what was perhaps the most important, ground-breaking electronic component created in the past century. µ

Best Ebooks for Digital Designing

1. Digital Design and Computer Architecture
2. Complete Digital Design: A Comprehensive Guide to Digital Electronics and Computer System Architecture
3. Schaum's Outline of Digital Principles
4. Digital Design: Principles and Practices Package (4th Edition)
5. Digital Design for Print and Web: An Introduction to Theory, Principles, and Techniques

Silicon Blue launches 40nm fgpas

Programmable logic developer Silicon Blue is sampling the iCE40 mobileFPGA family, which includes devices targeted at smartphones and tablets. Fabricated on TSMC's 40nm low power standard cmos process, the LP and HX families provide twice the logic capacity of the company's 65nm iCE65 devices. "We've proven our technology leadership with iCE65 and are on track to ship approximately 10million units this year," said ceo Kapil Shankar. The LP series, aimed at smartphones, and the HX series, designed with tablets in mind, offer sensor management and high speed custom connectivity. Silicon Blue calls its technology Custom Mobile Devices (CMDs). There are five devices in both series, with capacities ranging from 640 to 16,192 logic cells. However, while the HX range offers higher performance, it consumes more power. Both versions come in 2.5 x 2.5mm micro plastic bgas, Shankar added: "We've taken the next bold step with CMDs by extending video performance capability for smartphones to 525Mbit/s, enabling HD720p 60Hz (1280 x 720) and HD1080p 30Hz (1920 x 1080). For tablets, CMDs can now support WUXGA (1920x1200) with dual LVDS, HD720p 60Hz (1280x720) and HD1080p 30Hz (1920x1080)."

Another 40nm family, code named San Francisco, will be announced later in 2011.

Comparison Of Intel and AMD Processors

An overview of notebook and desktop processors offered by Intel and AMD.

What’s the big deal about choosing a processor?

The processor (also called CPU, short for Central Processing Unit) is the "engine" of a computer. It is the most important component in determining how fast or 'snappy' the system will operate across applications both now and in the near future.  Like the engine of an automobile, a processor can be fast, slow, power hungry or power efficient subject to the kind of work the computer is being considered for. It is important to round out what kind of things you will be doing on the system to best select a computer with a CPU most suitable to your needs.

Unlike other components of a notebook computer, the CPU is -- with rare exception -- a fixed component. This is in contrast to RAM and hard disk storage which can typically be upgraded. Therefore, another consideration is the fact that (important as the CPU is) the CPU you choose will be the same throughout the life of the system. This implies that as programs become more sophisticated, the computer's ability to handle such programs will be directly affected by the decision made at purchase all that time ago. This choice may mean the difference between a system that is useful for another year or two versus one that isn't -- much sooner. As a final consideration in choosing a CPU is the suggested or minimum requirements of either the programs that is planning on being run, or academic department recommendations as a guide as to the relative kind of performance required for a particular field of study.

The product line comparisons hierarchy 

Currently, the two largest manufacturers of CPUs in the world are Intel and AMD. The following provides a short profile of the companies and the current state of their products.

Intel

The current performance and market leader at the time of this writing is Intel.  Intel is currently the sole supplier of processors for all recent Apple computers (Macbook, Macbook Pro, Mini, iMac etc.) and are found in virtually all major computer manufacturer's product lineups. Intel's most current crop of CPUs are the Core iX-series processors which include the i3, i5 and i7; as of January 2011, these series of processors entered their 2nd generation (codenamed "Sandy Bridge" where the 1st generation was codenamed "Nehalem", differences explained under the special features section).  

AMD

AMD is the second largest supplier of processors for personal computers.  Many of their products are found in both high-performance and budget-oriented notebooks as well as low-cost, enthusiast-oriented desktop builds.  The Phenom II and Fusion platforms comprise AMD's most popular and mainstream offerings at the time of this writing.

Beneath, we provide a chart which compares the relative performance between competing product lines within Intel's and AMD's offerings. These are organized by the following three classes: high-end, mid-range and economy.  It is important to note that though this comparison offers a reference of relative performance within each brand, it does not necessarily indicate absolute rankings between competing Intel and AMD products (for instance, the Core i7 is in the same row and category as the Phenom II series but offers superior general performance). Further, the Core iX Mobile series only indicate relative performance for notebook platforms -- that is, it is generally not useful to compare them to desktop processors such as the Intel Core i7 or the Phenom II series.

High End Processors : Intensive Statistical Analysis, Professional Video/Audio Creation, Advanced 3D Graphics

(2nd generation "Sandy Bridge")

Intel Core i7 As Intel's flagship processor, the i7 is a 64-bit processor offering either 2, 4, or 6 cores of the highest levels of general performance available.  The i7 combines Hyper Threading and Turbo Boost technologies for the most demanding and advanced of applications.

Intel Core i7 Mobile Intel's Core i7 Mobile features unparalleled performance on notebooks, incorporating significant power savings while implementing the same features as the non-mobile i7, Hyper Threading and Turbo Boost. The i7 Mobile is available on notebooks with 2 or 4 cores; currently the 4 core version offers higher performance in some respects but heat and battery life are concerns.

AMD Phenom II X6 AMD's Phenom II X6 represents the industry's first consumer class six-core processor. The X6 offers the highest levels of performance ideal for the most intensive of tasks - bolstered by AMD's new Turbo Core technology, the X6 is able to optimize performance in a variety of situations.

(2nd generation "Sandy Bridge")

Intel Core i5 Based upon the same architecture as the i7, the i5 is also a 64-bit processor that features 2 or 4 cores at a similar class of performance of the i7 processor at a lower cost. The i5 features Turbo Boost and Hyper-Threading technology but do not possess as much cache memory as the i7.

Intel Core i5 Mobile The Intel Core i5 Mobile while also featuring Hyper Threading and Turbo Boost possesses a similar but lesser class of performance than the Core i7 Mobile with less cache and available in notebooks only with 2 cores. The Core i5 Mobile is a high performance processor with low energy requirements.

AMD Phenom II X4 AMD's latest generation of consumer class 4 core processors, the quad-core Phenom II X4 chips are designed to deliver performance ideal for all kinds of multimedia as well as in the most demanding of applications such as virtualization.

(2nd generation "Sandy Bridge")

Intel Core i3 Derived from the same architecture as the higher end i5 and i7, the i3 is available strictly as a dual core processor. Though Hyper Threading is available, it does not feature TurboBoost. The Core i3 processor presents higher levels of performance than the Core 2 at a smaller cost.

Intel Core i3 Mobile The Intel Core i3 Mobile descends similarly from the i3, presenting a fast, 64-bit computing experience with the intelligent architecture of the i5 Mobile and i7 Mobile. The i3 Mobile features 2 cores and Hyper Threading but does not include Turbo Boost technology

AMD Phenom II X3 & X2 AMD's Phenom X3 and X2 processors boast 3 or 2 cores that offer excellent performance value; great for all around usage on a small budget all while utilizing AMD's latest architecture technology seen in the Phenom II X4 series

Intel Core 2 Quad The Core 2 Quad features 4 processing cores to optimize gaming, video, and image processing. Built on the same architecture as the Core 2 Duo, this processor excels on multi-tasking with performance hungry applications.

Intel Core 2 Extreme Available in both 2 and 4 core versions, distinguishing features of the Extreme series include higher bus speeds than the non-extreme versions, and an unlocked clock multiplier for further customization of your computing performance.

Mid Range Processors : Speed & Multi-tasking, Adobe Creative Suit, All-Around Use, Basic 3D Graphics

Intel Core 2 Duo Contains two processing cores to optimize gaming, video, and image processing. Laptops with this chip tend to be thinner and and more energy-efficient.

AMD Phenom I X3 & Phenom I X4 AMD's first generation of consumer class processors featuring quad and triple core performance found in desktop builds. Features 64-bit computing performance as well as AMD's HyperTransport bus technology.

Intel Pentium Dual Core Dual core processor based on the Core microarchitecture. A class beneath the Core 2 Duo and Core Duo of Intel's processor offerings, the Pentium Dual Core is available in current desktops and laptops.

AMD Turion II Ultra / AMD Turion II The Turion II and Turion II Ultra are AMD's mainstream mobile processor platform; they provide excellent all-around performance for multimedia such as high definition video. As these are often paired with AMD/ATI graphics, budget configurations containing these processors are also sufficient for basic 3D graphics and gaming.

Intel Core Duo / Intel Core Solo The Intel Core Duo and Core Solo are dual and single core processors based on the Core microarchitecture. The Core Duo and Core Solo offers modest performance for office and limited multimedia oriented tasks.

AMD Athlon II X2 The AMD Athlon II X2 is a 2 core desktop processor that is 80% faster than it's single core counterpart. Great for multitasking and multimedia consumption on a budget.

Economy Processors : Internet Browsing, E-mail, Microsoft Office, Simple Graphics and Games

Intel Centrino/Centrino Duo A mobile-oriented processor based upon Pentium M or Core Duo architectures; the Centrino also integrates wireless networking technology allowing for smaller sized laptops. Offers slight performance boost over simply choosing a core duo and dell wireless card (which is typically less expensive.)

AMD Sempron The AMD Sempron is a budget class processor seen in low cost notebooks and desktops and are considered a class above netbook/nettop processors such as the Intel Atom or the AMD Neo platforms.

Intel Atom Primarily found in netbooks and nettops, this processor has been designed with price and power consumption in mind. As a result, it offers much less processing power than other current Intel alternatives. This processor is available in 1 or 2 cores, with the single core option being far more prevalent.

AMD Athlon Neo / Neo X2 The Athlon Neo and Neo X2 are single and dual core processors seen in ultra-mobile platforms such as netbook and nettops. They are featured with ATI integrated graphics for reasonable multimedia playback performance.

Intel Celeron Intel's economy model processor. It is the most basic, and thus the slowest. It has less cache than other Intel processors, so even if it has the same Ghz rating as another processor, it will be slower. We usually do not recommend this processor because it offers the least in terms of longevity.

 

Benchmarks

This is not meant to be a comprehensive list, but rather a way to identify different branches in processors. To see a more comprehensive comparison of specific processor types, follow the benchmark links below. Benchmark websites rank processors within and between series. The highest rated processors are typically used for server applications and for simplicity, those products are omitted in the set of rankings above (eg. Intel Xeon and AMD Opteron); rather the processors that are found in desktops and notebooks are included.

It is further important to recognize that general processor speed is not solely atttributed by its frequency -- these are the Mhz and Ghz numbers often seen -- of the processor when comparing between different product lines as is the common misconception. For instance, an Intel Pentium 4 3.8 Ghz processor is slower than an Intel Core Duo or AMD Phenom. The primary reasons for this is a function of the architecture and the associated features therein (particulrly additional physical cores, advancing of bus technology, etc). It is thus, only applicable comparing frequency ratings to ascertain relative performance within exact product lines (eg. Core 2 Duo vs. Core 2 Duo). The chart beneath will give a rough idea of the hierarchy of performance expected in faring against competing product lines at the time of this writing. It may also be helpful to understand that versions of processors found in desktops tend to be higher in performance than their notebook counterparts of the same product line; this is done to maintain thermal requirements, battery life and minimize size at the cost of speed.

Benchmark Links:

http://www.cpubenchmark.net/

Desktop CPU Benchmarks:

http://www.tomshardware.com/charts/desktop-cpu-charts-q3-2008/benchmarks,31.html

Mobile CPU Benchmarks:

http://www.tomshardware.com/charts/mobile-cpu-charts/benchmarks,19.html

Product Information from Manufacturers:

Intel's Processor site:

http://www.intel.com/products/processor/index.htm

AMD's Processor site:

http://www.amd.com/us-en/Processors/ProductInformation/0,,30_118,00.html

 

Special Features Explained

In this section, we breakdown the practical meaning of some important technical features included in the various processors available. Please not that this is not a comprehensive listing and what is described are the most common/relevant features offered.

Special Features	Explanation	Processors Using Feature
Intel Features
Hyper Threading	The operating system treats the processor as two processors instead of one. This increases the speed of the computer.	Pentium 4, Core i7, Core i5, Core i3
Turbo Boost	Allows the processor to intelligently overclock themselves so long as thermal and electrical requirements are still met.	Core i7, Core i5
Intel QuickPath Interconnect (QPI)	A new Intel technology which replaced Front Side Bus (FSB) -- similar in purpose to AMD's competing HyperTransport technology.	Implemented in some fashion in all Intel core iX series processors
Execute Disable Bit	Prevents certain viruses from infecting the system by labeling some data "executable."	Current Intel processors
vPro	Best for IT people trying to maintain several workstations. It is able to detect systems, even in powered-off states. Synchronizes remote desktop, security, and other multi-station support features. Decreases desk-side maintenance visits.	Core Duo, Core 2 Duo
ViiV technology	Intel's bundle for enhancing multimedia. Supports HD resolutions 720p up to 1080i.	Pentium D, Extreme, Core Duo, Core 2: Duo, Extreme, Quad.
AMD Features
Hyper Transport	Feature that allows for faster processing speed and better energy efficiency.	Current AMD processors
Cool'n'Quiet	Reduces heat and noise of processors allowing for increased energy efficiency.	Phenom I & II, Athlon, Sempron (with exceptions)
Turbo Core	Turbo Core allows for contextual overclocking of the processor to optimize performance subject to electrical and thermal requirements/specifications.	Phenom II X6
CoolCore	Limits unused elements of the processor such that power is conserved -- allows for increased notebook battery life on a single charge.	Phenom I & II, Turion
Dynamic Power Management	Allows for dynamic power management to optimize energy consumption while maintaining performance levels.	Phenom I & II, Turion