Nohau -


When Intel introduced the microprocessor in 1971 they quickly realizedthat the embedded apps spawned by this new invention were verydifferent than conventional computer systems.

Most had neither a keyboard nor a display, at least not one like thethen-common VT-100 (DEC CRT terminals) or ASR-33 (beastly-loudmechanical teletypewriters). Programs lived in ROM. Developers hadlittle visibility into what their code was doing.

They introduced the Intellec, a development platform originally forthe 4004 and later the 8008. Intellecs were computers themselves with aUART for communication with a standard terminal. But many users,including yours truly, hotwired the unit's bus to that of the embeddedsystem we were developing. Then one could download and (very tediously)debug applications.

By the mid-70s the company finally invented the true In-CircuitEmulator (ICE) in the guise of their MDS-800, then as now colloquiallyknown as the “Blue Box”. Packaged with the optional ICE boards theseunits cost some $20k, about $79k in today's dollars, and had dual 8″floppy disks, each of which stored 80KB if memory serves.

We swapped disks a lot.

ICEs came to dominate embedded development. By the 80s numerouscompanies specialized in these sorts of tools. The largest was AppliedMicrosystems, which at their peak sold some $40m worth of emulatorsevery year.

The 80s and 90s were the glory days of emulators; they wereconsidered so essential that microprocessor vendors routinely andgenerously funded ICE companies to develop a tool for each new CPU.Costs dropped; for many processors the tools were just a handful ofthousands of dollars.

Then the ICE world imploded.

Higher speeds, difficult-to-probe IC packages, and complex speedboosters (like caches, pipelines, MMUs, etc) all conspired to makeemulators problematic at best. Motorola, TI and others introduced BDMand JTAG interfaces for debugging. IC vendors mostly stopped makingbond-out versions of their chips, special high-pin count variants usedonly by ICE companies to create more visibility into the processors.

Applied Microsystems essentially failed in 2002. Many other emulatorvendors weren't far behind. The industry is now a shell of its formerself.

One of the giants of the business was Nohau, which originallyspecialized in emulators for the 8051 and derivatives. Over time theyexpanded into a number of other microcontrollers and to higher-endCPUs. They, too, joined the BDM revolution while continuing to offertraditional ICEs as well.

Nohau was privately-held so never published sales data, but my guess” and it's only a guess ” pegged their yearly sales around the $10mmark during their heyday. That's a pretty small company, but in thesmall world of emulators was huge.

Nohau produced much more than a line of debugging products. Theydeveloped a sterling reputation as a company insanely responsive tocustomers, and one that sold a very high-quality line of products, atrait that often eluded some other ICE vendors. At the Embedded SystemsConferences their big booth was always packed with happy customers andinterested prospects.

The technology challenges that hit other ICE vendors didn't leaveNohau unspared. Business changed, and then shrank. They disappearedfrom the ESC and their ads were no longer so prominent.

This year their parent company went bankrupt and Nohau itselfstopped operations, due, according to my sources, more to legal issuesunrelated to the emulator business than a lack of business. I wassaddened when I heard that this great company and theirhighly-respected line of tools disappeared.

But in late-breaking news, the product line has been rescued by IceTechnology . Owner Joe Pennese, long an emulator man and Nohau rep,bought the company's product line. He told me that sales are far aboveexpectations.

Though I remain saddened at the scattering of Nohau's excellentstaff, it's nice to know their products live on.

Do note that Nohau in the rest of the world is still alive and doingwell, but according to their web sites, no longer sell the Nohau brandof emulator.

Do you have stories of using their products?

Jack G. Ganssle is a lecturer and consultant on embeddeddevelopment issues. He conducts seminars on embedded systems and helpscompanies with their embedded challenges. Contact him at . His website is

Wow! Talk about memory lane! ok Jack, you asked for it. By the way, I live in Saratoga, and my 1st office as a consultant, was located in Santa Clara.


Many years ago, I decided to start a business in consulting. At first, it was to be mainly hardware design with some microprocessor work. However, I quickly came to realize that the embedded microcontroller was gonna be really big …. I mean really big!

So, I did a survey, and found that I really wanted to base my expertise around Intels MCS8051 chip. I decided that this MCU was going to be even bigger and more ubiquitous than most of the current 808x, 68HCxx and Z8x variants out there.

So, I basically start searching for development/debugging tools. One of my consulting buddies tells me that one of his clients purchased an emulator from a brand new company called NOHAU, and that I oughta check it out.

I was very impressed with what I saw. So; I did two things;
– I purchased version 1.3 of the, then Archimedes 'C' compiler/toolkit for the 8051
– I purchased one of the first 8051 emulators.

Another interesting thing about my first purchase. I called Ollie Hallengren, the consultant who started NOHAU. He told me that his office was over in Campbell. Basically he told me that he was a consultant and found that there were no really good tools for the 8051. So he made one himself.

I drove over to his office, and sure enough, he had a couple of those lab tables sprawled out, and had a couple of fellows working with him. It looked every bit the independent embedded systems consultant digs! We shook hands, and chatted for a bit. Then he went over to his 'bone-yard'/parts closet, and pulled out a box that had an emulator in it. I wrote him a check there on the spot for $1500 I believe.

That is basically how I started my business! Have NOHAU, will travel! Pretty nifty eh?

– Ken Wada.

ChipView + Nohau for the 8051 is an unbeatable combination. But I've not always used ChipView.

When I came back from Christmas vacation, January 2000, I found that their EMUL51 DOS emulator package was affected by the Y2K bug, and that it was incompatible with files generated containing dates with Y2K or later.

It seemed then I was the only one who used the old DOS program because Mike Quirk at Nohau at first claimed the problem was the compiler maker's, not theirs, etc., until finally after I explained carefully over several days how it was their problem that they went ahead and fixed it, almost. To this day, when a file loads, the program says 19100, 19101 .. 19107, respective to 2000, 2001 .. 2007.

– Matthew Staben

Good ol days indeed.

I started with the KIM board (6502) to S-100 / 8080 / z80 (Godbout, CompuPro, et al) based computers. Cut my teeth on Intel blue boxes that must have been made of depleted uranium to weigh as much as they did and I remember them costing up to $60K in those day's dollars. At one point I was using two of them (on either side of a communications protocol that I created) to debug and test the system. That was during the pre-offshore Engineering days when tying up $120K in development hardware was a big deal, but during those times, product quality was more important than the cheapest vendor that can be found in the world. This development effort resulted in a ventilator that is still in use today, I can't begin to imagine the number of people who must have been saved by this one device. And all that with the most primitive of tools.

I remember we used to keep a large chunk of green bar fan fold paper in the middle of the main Engineering room, where we would hand document errors and bugs with the assembler, PL/M compiler, and ICE. Periodically we would send this off to Intel to get fixed and we would get calls back from native English speaking Engineers inside of Intel who where fixing the bugs, looking for clarification or opinions on if a potential new feature was desirable, etc; today you're lucky if you can get an accurate datasheet from a semiconductor company.

I then got to use the Signum Systems 8048 ICE that was an S-100 card running in text mode under CP/M. And later graduated to the 8051 ICE for that same platform. Made the move to DOS and then Windows based PCs again running the latest variant of the Signum Systems ICE for the latest flavour of the 8051 family.

That's when I ran into a NOHAU ICE, we in Engineering quickly came up with the tag line for NOHAU which was No how, No way!. Which was pretty funny back in those days (they where simple times). I remember paying good money for a third party application program (I forget its name) to run in place of the crappy application that shipped with the NOHAU ICE hardware. This separate application would provide a decent environment in which to debug. Principally it would backfill breakpoints in the NOHAU hardware with NOPs and then replace with the correct code after a break because NOHAU couldn't break without skidding passed the intended breakpoint! All this without any CPU cache to get in the way.

With today's BDM / JTAG debuggers I find myself frequently missing the excellent Signum System ICEs and yes even an old NOHAU ICE would be better than most of the debuggers that we get today.

I think there is an unspoken Inverse Moore's Law for embedded development tools, something to the effect that every 24 months the capabilities of embedded development tools halves.

-Chris Gates

It is unfortunate that the Knowit LLC bankruptcy was visited on the Nohau name.

To the loyal Nohau users out there, production has started in our new facility in San Jose California. Mike Quirk, who has been supporting Nohau emulators for over 17 years, back on the job, too. He can be reached at

It's worth mentioning that humble Jack G. made his share of contributions to in-circuit emulator technology in the early days, and wrote the Embedded Systems Dictionary. Thank you for the article Mr. Ganssle

– Joe Pennese

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