I Have Seen The Future...
by Darren Ashby

I have had a vision. Read on to learn the wave of the future. Of course, I am banking on the fact that prophets are often remembered for their hits more than their misses. So I figure I'll go out on a limb and say that the future of low cost micro-controllers is something with a bit of everything.

Take a look at the Cypress PSoC device. I can't really call it a micro, because it is much more than that. In fact when we first fired it up at work, I found my analog background quite useful to one of my extremely bright yet digital engineers. I looked at this part and said to myself wow, what an idea! I figured I'd wait a bit before writing about it though, to see if it really is all it's cracked up to be. Well to sum it up, it is. Not to say there aren't some things I would change and areas for improvement, but for a first shot, Cypress hit it 'out of the park' with this one.

If you haven't heard of PSoC let me explain a little. First take a decent 8-bit micro, marry it up to a PLD, throw op-amps and switching circuits at the wedding in lieu of rice, and viola, you have the PSoC. It is a combination of all these parts into a single re-programmable apparatus. You can set up the programmable logic to perform all sorts of counters, PWM generators, mutiplexers and other items. There are a group of analog blocks that can be configured as filters, amplifiers, comparators, differential amps, analog to digital converters and other items. (We even made a rectifier circuit inside this puppy.) It's basically an ASIC that you can program to be what you want, when you want, and even change on the fly.

For some time now, the real world has been driving the micro world to deal more and more with analog signals. How many low cost micros with a built in A to D have you seen lately? This is true of the Tiny 15 I praised so highly in my TSMC series. It even has a built in 20X amplifier. But the PSoC takes all that to a whole new level. This is a level that once you have been exposed to it makes it very hard to go back.

Now I must be true to my roots of giving an honest opinion. The PSoC is not all wine and roses. There are a few issues I have with it. The first question I asked when we were introduced to the analog blocks was, "how do I hook up to the negative feedback of the op-amp?" There is no way to do that... yet. Apparently I'm not the only one that asked that question and the answer is planned for the next version. The other complaint I have heard, but hasn't really affected us, is a fairly high noise floor. As I've been told, this is due to all the switching going on and improvements are in the works. Probably the most irritating thing that we have had issue with is the input/output rails of the op-amps. They hark back to the days you had to stay almost a volt off of the top and bottom rails to prevent clipping. This was a conscious choice to keep the cost of the part down and I applaud that effort. Cost is always a major factor in consumer products, but I would have been happy with an op-amp that could swing to the bottom rail, you know like the lowly LM324 you can get for about 8 cents. To Cypress' credit, they developed a work around for us and you guessed it, improvements are already planned for the next version.

One big potential drawback to marketing this device (not the micro itself, but the effort of acquiring market share) is the fact that it is so new and different that engineers will have a tough time picking it up. But Cypress has addressed that with some excellent customer service in the form of web support, access to Cypress engineers, and even phone training sessions. I rate the customer support we have received on this device as excellent.

You might say, now that's all great Darren, but how can you say this is the future? You might even point out that some similar devices have been out there already, and the world hasn't changed ⁱ. I have but one thing to say. You can buy this at about the same price as a comparable plain old micro. Which would you rather have, the device that eliminates almost all of your analog components, sucking them all into your chip, or the much larger PCB with all those signal conditioning amplifiers just to get it to a level you can read with your A to D? In the last 8 weeks, we have already found two applications for it that are in full development, and a third on the drawing board. This chip hits the sweet spot between price and performance in a big way, and that is the mark of a winner.

The real world is analog, and we all live in the real world ⁱⁱ. The correlation is that our micros need to live there too. So far no chip I have seen has done it better than this one. I honestly believe the PSoC paves the way of things to come.

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Footnotes

ⁱ So many things claim to change the world now days, the segway HT comes to mind, but do you think an $8000.00 scooter with a range of 10 miles can change the way the world goes to work? I personally think an $80 scooter would have a great chance, or something with more range. It just doesn't add up. As Bill would say, you need the killer app to really shake things up.

ⁱⁱ OK, I can't say for sure that my brother connects with the analog world :), but he is learning. Just check out these great write-ups on the PsoC:
http://www.chipcenter.com/eexpert/rashby/rashby049.html
http://www.chipcenter.com/eexpert/rashby/rashby058.html
http://www.chipcenter.com/eexpert/rashby/rashby061.html

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