Embedded Systems Design - March 2008 - (Page 42)

0308esd.p41to46 2/14/08 3:28 PM Page 42 20 years ago more attractive anyway. Most obviously, the pins in a PLD can be configured as they’re needed, an advantage for functions that involve switches, indicators, and control lines. Less obviously, PLDs are easy to test. In fact, most PLD development systems can automatically generate a test suite for the part. PLDs can also operate much faster than a microcontroller in the same price range. There are nevertheless a number of strictures on PLD implementation. The prime restriction is that the least expensive PLDs offer only eight register bits; having more than a few dozen bits automatically puts the price of the chip over $10. Recent innovations in PLD development system technology are moving PLD design back into the software realm. One expert system for PLD selection from Mine Inc. (Colorado Springs, Colo.), PLDesigner, integrates schematic and HDL environments with simulation and a knowledgebased software mechanism that selects the most appropriate PLD. Systems designers can enter the restrictive parameters necessary for the application, such as cost, speed, device count, power consumption, lead time to delivery, and distribution channels. PLDesigner then tests how well the function fits onto each and every possible combination of PLDs and produces a list of suggested implementation configurations. The PLDesigner development system will be supplied by the leading electronics design system vendor, Mentor Graphics (Beaverton, Ore.). Since Mentor has selected Minc as its sole PLD design tool source, we may trust that PLDesigner really works. DESCRIBING YOUR FUNCTION The three most prominent PLD HDLs are found in PALASM, CUPL, and ABEL. PALASM, the first development system for PLD design, was supplied free by Monolithic Memories. Unfortunately, it could only design Monolithic’s own PLDs. (Monolithic Memories is now a part of Advanced Micro Devices, Sunnyvale, Calif.) CUPL is similar to PALASM and is available from a number of PLD vendors. A $50 starter kit containing the full CUPL program (but only configuration files for four PLD architectures) is available from Texas Instruments (Austin, Texas). ABEL is the most flexible of these development systems. Although similar to PALASM and CUPL in the way it’s used, ABEL supports many PLD architectures and some more advanced HDL commands. Unfortunately, it’s still necessary to select the PLD architecture into which you want to compile the functional description and declare the pin usage for that PLD. 42 MARCH 2008 | embedded systems design | www.embedded.com http://www.lauterbach.com http://www.lauterbach.de http://www.lauterbach.co.uk http://www.lauterbach.it http://www.lauterbach.cn http://www.lauterbach.co.jp http://www.lauterbach.com http://www.embedded.com

Table of Contents Feed for the Digital Edition of Embedded Systems Design - March 2008

Embedded Systems Design - March 2008 Contents #Include Programming Pointers Designing DSP-based Motor Control Using Fuzzy Logic Hardware/Software Verification Enters the Atomic Age Efficient CRC Calculation with Minimal Memory Footprint Programming Your Own Microcontroller Advertising Index Break Points Marketplace

Embedded Systems Design - March 2008

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