Intel 80C32

Just buy the 80C32 (or equivalent) from someone else. You could consider a slight redesign to use on-board flash rather than external program memory, but that might not be worth it if your quantities are small. Test EMC issues carefully before releasing it, in any case.

Best regards, Spehro Pefhany

Hardly anyone buys them from Intel any more anyway!

Are you not aware how widely 'second-sourced' it is ?

Graham

Look at Atmel, Philips, Dallas.

I am not familiar with the C32 but more with the C51. The sole reason why I often kept coming back to that old eight-banger was that it is about the only processor family that is truly second-sourced. Sometimes the firmware gurus said that was like placing an order for a DC-3 aircraft. But heck, they work (both the C51 and the DC-3).

At one time we bought another brand. Sometimes those acted "spooky" while the Intel didn't. It was a simple solution at the time. May be time to go bact to someone else. Thanks

My sentiments exactly. It is in an industrial controller, hardly cutting edge, and certainly proven that it works. Customer likes that feature. "Why fix it if it ain't broken"?

That shouldn't happen you know.

YW.

I have recently tended to use the Philips and Atmel flavours.

Graham

That could mean that some timing or the reset is running borderline. If so it needs to be fixed because even a slight process variation from the same vendor could push this product over the cliff.

Take a look at the reset circuitry. The cheap RC solution that is often published in app notes doesn't cut it.

It's worked fine for me but I don't rely on the on-chip parasitic diode to avoid over-volting the reset input.

Graham

Hello Graham,

avoid

The RC scheme can really fall apart when the power supply comes up a bit sluggish or goes through a wee brown-out. The worst case is when it didn't quite catch a dip and now the uC "kind of" works and behaves like a backfiring engine until you power-cycle it. I usually provide my own reset so that the uC sees a clean transition.

avoid

I can see what you mean. The stuff I've designed it into doesn't suffer sluggish power rail start-up. In the event of a brown out causing trouble I reckon most ppl would cycle the power.

You've specifically seen this behaviour ?

Graham

avoid

Also, the R/C reset seems to get flaky as the equipment ages. I had to modify a rack full of editing interfaces for VTRs at a TV station because the OEM redesigned the circuit and removed the reset circuit the board was laid out to use. You do not want to be flipping dozens power switches repeatedly when you need to finish editing a tape an hour ago.

Lucky bastard :-)) Last time I used the RC reset, I burned my fingers badly. Had to pay shipping a device from and to the US. Power your circuit with a wall-wart and plug/unplug it quickly. You'll see the uC will start to execute code at random without a proper reset circuit. Anyway, I've stopped using the 8051 series.

Hello Graham,

avoid

sluggish power

would

Sure they do but their anger level ratchets up one notch every time that happens. Like the way it does when the message appears "Acrobat has generated errors..." and the whole PC is shot for minutes.

Oh yeah, lots. Ripped out many RC "resets" and replaced them with something that works. I believe that part of the unreliability in X-10 powerline gear is also related to that. Will fix it some day but that stuff ain't that high on the food chain. My wife wants the east side decking repaired first ;-)

Hello Michael,

Sometimes it does. Once while repairing a piece of (rather expensive) equipment I found that they had used a, gasp, electrolytic in the reset. This meant the time constant shrunk over time as it dried out until it became unbearable. I ripped it out and replaced it with a proper circuit.

Then there are the electrolytics in the power suplies. When fresh they provide enough capacitance to weather a wee notch in the mains supply from turning on a big load somewhere. So the RC reset doesn't get triggered as much. As these caps age that ability is often reduced and the number of hang-ups due to a lousy RC reset can increase.

As a consultant it's my life, to some extent, to correct other engineer's bugs. That's ok, I get paid for it and never spread blame. However, when I have to fix rather obvious bugs in equipment that I bought as an end user that isn't so nice. It leaving that nagging concern about what else might be "sub-optimal" in there.

Hello Nico,

avoid

You can use the 8051 family. Just give them a proper reset, your own circuit or a good chip. Even modern uCs such as the MSP430 came out with resets that were way too crude for my taste. Now many of them contain better resets that can handle brown-outs. I always wonder what on earth takes them that long to get it licked.

(Messy) relatively precise (and wide voltage range) analog, created in a digital process?

Best regards, Spehro Pefhany

avoid

I have other reasons not to use the 8051, the reset is least of the 'problems' I have with it. You are right about the MSP430. I took me some time to figure out why my co-workers had so many problems using a USB powered gadget I made which uses the MSP430 as a uC. It turned out the USB port of the laptop they used output a surge of a few volts which never drops below 0.6 volts after shutting down. Sh*t!

Do tell.

Graham

Hello Spehro,

Not really. Many uCs offer superb on-board ADCs, PGAs and whatnot up to