Last week I looked at some of the preliminary responses from the 2005 readership survey. One comment in particular jumped out at me. Someone noted he/she would like to see more old projects revamped with up-to-date hardware. For that reader, and anyone else who shares the same interest, this month we have a pair of articles about effective updates to two different pulse generator projects.

First up we have Tom Napier’s article, “Real-Time Pulse Generator” (page 18). Tom’s original TTL-level pulse generator was designed around a Microchip 20-MHz PIC16C55 microcontroller. It generated pulses from 0.1 µs to 0.99 s long. In the 1990s, the 20-MHz microcontroller was sufficient for Tom’s needs. But in 2005, 20 MHz pales in comparison to what’s available with new devices. The introduction of 40-MHz PIC16C5x chips opened the door to new possibilities for this old project. By redesigning his project around the latest PIC16C55, Tom doubled the clock speed and vastly improved the system’s performance. The minimum pulse period improved from 5 to 3 µs. Along the way, Tom also took the opportunity to simplify his original code. Although Tom’s original design served its purpose, the end result of the redesign is a more efficient and more useful tool.

Brian Millier also recently took advantage of newly released hardware to improve a pulse generator he designed in the late ’90s (page 59). Built around an Am9513 from Advanced Micro Devices, the original project lacked the kind of power Brian was looking for. He found that power almost a decade later by upgrading to a Cypress PSoC. Restructuring the project around a CY8C27443 microcontroller enabled Brian to achieve his goal of generating pulses below 100 ns. As Brian explains, the versatility of the CY8C27443 microcontroller’s internal and external clocking options was a critical factor in the success of his redesign.

There’s a lesson to be learned here: Don’t discard your old projects. Whether you reluctantly designed a mediocre project at a time when better hardware simply wasn’t accessible or you realize your formerly up-to-date project is unimpressive by today’s standards, you probably have the start of a solid, useful project. New hardware that offers more processing power, faster speed, and enhanced flexibility can help you modernize your original projects. Tom and Brian’s refined pulse generators showcase what can be achieved when you combine cutting-edge technology with classic ideas.

jennifer.huber@circuitcellar.com