what makes computers 'Embedded"

You do know that the 1802 is from the 1970's era... ?

The super-short description (that I give folks at cocktail parties -- i.e., folks who *really* don't want to know details) is: "a computer that doesn't *look* like a Computer" (i.e., since most folks equate computers with PC's or Mac's). I then rattle off half a dozen *typical* devices that I am quite sure they have dealt with often in their life: gasoline pumps, slot machines, (modern) sewing machine, microwave oven, etc.

A processor, itself, is no more "embedded" than a *resistor*. I.e., any processor could (conceivably) be used *in* an embedded system. *Many* processors used in embedded devices can also be used as the basis for a "desktop" (i.e., non embedded) system -- though the market has tended to focus on just the Mac and PC platforms.

The 1802 is a very old part. :> Google "COSMAC" and you may find some documentation on sample development boards that you could copy. The advantages something like an 1802 will have are low power and slow. I.e., you can safely wirewrap something like this without having to fret over power supply decoupling, wire routing, etc.

Doesn't cost anything to ask! :>

Good luck!

If you have been reading for "a long time" and are "old" then I think you would have seen long discussions about this in this group and would likely have more than all you need to decide for yourself what you want to take away as defining the term.

That depends upon your perspective.

If you are an end-user, then it might be best to see it as any cpu that provides support functions but where that cpu's functions aren't sold as the end-use.

If you are a programmer type, then it might be best to see it as any cpu that requires skill sets and possibly hardware and software support tools which are markedly different from the skill sets and tools used to program cpus which _are_ sold as the end-use to consumers.

This last line isn't static, nor is it defined by a specific device. Instead, it defines the environment, skill sets, and specialized tools required to get a job done.

If you are programming a TI-89 using its high level language to do so, it's hard to call yourself an embedded programmer or say that you are programming an embedded computer. The calculator is _sold_ as such a device, in the first place, and you aren't requiring specialized skills or tools to do the programming. All of the difficult stuff has already been managed for you by those actually _doing_ embedded programming, so that you don't have to. However, if you were programming the TI-89 at a low enough level that you did require specialized skills and tools to do so, then you would be doing embedded programming and the device would be an embedded computer in that context.

Of course, if you hooked that TI-89 up to an interface that controlled something like a microwave oven, for example, then it's more likely you'd be doing embedded programming in the way I see it.

It depends on what you are doing with it. If someone has already created the device for you and has ported CP/M to it, so that all you are doing is using BASIC (let's say) to do some general programming that generated some digits of PI as its output, I'd hardly call that embedded programming.

On the other hand, if you took that same unit _and_ used the very same BASIC language within it and applied yourself to the task of doing PID control of the temperature at a chicken hatchery, then I think it WOULD be embedded programming. You'd likely require some specialized skills, at the very least, but also perhaps have to use other specialized tools in making sure that the results met the application needs.

And such end-use is certainly nothing similar. So the end-user of the unit would also consider it "embedded."

Tried? Did it not work out?

Jon

snipped-for-privacy@g19g2000yqe.googlegroups.com...

And it's still going strong in its niche.

It's the software that's embedded, not the processor. A cellphone has software pre-loaded in it and won't work without it. A PC comes with embedded software in it's BIOS (and won't work without it) whereas the operating system software in a PC is non embedded because you load it from a hard drive etc when you power up. Most embedded software these days is in re-programmable flash memory but a lot used to be in OTP (One time programmable memory) and to change the software, you had to physically remove the chip and replace it.

Bury that processor in another piece of equipment and it's embedded.

AS I recall the Voyager spacecraft have 1802s on board. They were chosen for their low power consumption and radiation-resistance (being CMOS rather than NMOS) and they are still running over thirty years since the Voyagers were launched.

CMOS with a HUGE device geometry. And happy running on anything from 5 to 15V, which makes voltage regulation easy.

They're still available in a silicon-on-sapphire version, for something like $150 a pop in the original 40-pin package, and as far as I know they're still used in space applications where their rather modest performance is adequate to the task.

IIRC, they were also fully static (unlike many other processors of the day). You could clock them at 1Hz and watch the bus lines change in "real time" if you wanted to.

The SOS construction prevents latch-up.

I was at visiting Harris (was RCA) around the time that Voyager was passing one of its milestone. An engineer at lunch had his retirement delayed for a few months in case he was needed. He had taped out the 1802 masks.

A few hundred gates with geometry's big enough to ignore random radiation energy spikes.

Regards,

Walter..

-- Walter Banks Byte Craft Limited

...and since he's already at Google, it's duck soup finding them:

The link in your signature doesn't work. If you type in westcottdesign.com (not noticing it's wescott rather than westcott) you get taken to a wine seller!

Odd -- it works from here, but then it's hosted on my ISP's site.

Actually westcottdesign.com isn't a wine seller -- she sells graphics design services, including wine _labels_. I had an email conversation with her shortly after I registered the domain -- for every creative way to misconstrue a verbal attempt to guide how to spell Wescott when you really want to spell it 'Westcott', there's one that goes the other way.

I liked 'Wescottt' the best (If you say "Wescott with two 't's" you'll often end up with "Westcot").

At least my name isn't Smyth.

es

Viewing the web page source for the one that doesn't work I see href=3D"

For one that works (early 2009) href=3D"

http is missing from the first one. I'm using google chrome but it doesn't work in Internet Explorer either.

For instance the US 1950's missile defense system (NORAD) was definitively an embedded system with hundreds of rack mounted tube computers with a single mission.

OTOH, any wrist watch these days will perform nearly the same calculations :-).

gamma wrote: (badly blockquoting 5 layers deep)

Your problem is Google Groups. Google, in an effort to even more closely monitor your activities, has recently taken to redirecting links clicked on Google Groups thru 1 additional layer. They have done a poor job of this. Tim's site is the first one I have seen fail outright. When I use Google Groups and Ctrl-click URLs, I click Stop or hit the Esc key quickly and edit the junk out of the link.

Have you considered using a REAL Usenet newsreader?

If you are going to continue to use Google to post to Usenet, click **More options** then Ctrl-click the *Reply* link that shows up **there**. It does a MUCH better job of auto-blockquoting than the *Reply* link that is in plain sight.

...and DO trim some of the blockquoting when you post.

Can you recommend a news server?