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Issue #233 December 2009
Looking Back While Moving Forward
by C. J. Abate
Here we are at the end of 2009. And now begins the transitional period of time when you start planning future designs while taking stock of your past projects. To help you through this exciting yet overwhelming time of year, we purposely put together an issue that includes articles by designers who excel at forging ahead with new projects by implementing the parts they’ve acquired and the lessons they’ve learned.
The first article in this vein is “Retrocomputing on an FPGA” by Stephen A. Edwards (p. 24). In it he describes how to reconstruct an old Apple II computer with programmable logic. This is an excellent example of how to use modern development techniques to combine old and new parts in an interesting design.
Stephen isn’t the only Circuit Cellar writer who has been thinking about the Apple II during the last few months. In “Digital Modulations Demystified,” columnist Robert Lacoste reminisces about the day he connected his first 300-bps modem to his Apple II (p. 54). He considers the differences between old and new data transmission speeds and then explains the complicated theory and mathematics associated with the sometimes mystifying subject of digital modulations. With this information, you’ll be a step ahead of the game when you start your next project that requires data transmission, which is probably your very next one.
In other retro-design-related news, one of Ed Nisley’s friends recently discovered that “memories are not forever” when he tried to start up a Tektronix 492 spectrum analyzer. Guess what happened. Failure. Fortunately, Ed came to the rescue with some digital logic and firmware. The details begin on page 44.
And what would a discussion of old and new technology be without touching on the topic of the I2C bus? Turn to page 64 where Jeff Bachiochi explains how to extend and isolate the I2C bus. If you have a robotics design on tap, you may find Jeff’s contemporary take on this ’80s-era concept to be extremely helpful.
Don’t worry, we also have content for those of you looking for articles on technologies and projects that aren’t so focused on the past-present connection. First, check out Thomas Mitchell’s article, “Building Microprogrammed Machines with FPGAs” (p. 36). He details an interesting alternative to hardwired finite state machines.
Next, jump to page 70, where Tom Cantrell presents exciting new technology that’s sure to get you thinking about possible wireless IP designs, from small wireless embedded apps to large ’Net-connected systems. As you’ll see, the Internet doesn’t have to be everywhere, but it can be if that’s what you want.
Finally, remember that the 2010 WIZnet iMCU Design Contest is well underway. Dave Tweed’s article “iMCU W7100” will help you started your design (p. 14). Be sure to enter your project by June 30, 2010. Good luck!
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