74HC123 and long pulse

On a sunny day (Sun, 10 May 2009 11:49:25 +0200) it happened Marco Trapanese wrote in :

PIC LOL

MC14538 will do 20 seconds easy. 2u2+10M so 100N+512K will do

500mS.....tolerance/accuracy is up to you.

TTman ha scritto:

Great! That's what I was looking for.

Marco

NE555 NE556 NE558

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HC123 should be able to do seconds or minutes. Just use the right RC. But it does need an RC per one-shot.

John

LM555 or mc1455

Cheers

I prefer 'HC4538 for such long-time-constant tasks.

...Jim Thompson

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On a sunny day (Sun, 10 May 2009 13:33:06 -0400) it happened "Martin Riddle" wrote in :

Yes those will work, but then require 4 caps and 4 resistors at least. With 4 inputs, 4 outputs, 2 power, a 14 Ppin PIC will do, and have prosessing to spare that could possibly be used for something too. Like for example a 16F505

NO external components needed, use internal RC oscillaor. You can use 4 port interrupts and look in the interrupt routine which one it was, and start a counter. Main routine can do software increment of the counters and set outputs after so many ms, with quite a high accuray. There are many other ways to do it too.

Why keep all that antique analog stuff around?

On a sunny day (Sun, 10 May 2009 18:03:20 GMT) it happened Jan Panteltje wrote in :

PS and PIC16F505 is 61 Euro cents for 1 piece, can you buy 4 555, 4 caps, 4 resistors for that? Plus the board space?

I like these facts:

Temperature Range (C) -40 to 125 Operating Voltage Range (V) 2 to 5.5

How long would the caps last at 125C ?

don

Jan Panteltje ha scritto:

I bet a PIC couldn't update outputs after 20 ns...

Marco

Because it doesn't need a dev system, doesn't need to have code written and debugged, doesn't need chips to be programmed on a production basis, doesn't need a JTAG header, isn't threatened by parts going obsolete, doesn't need reprogramming to change delays, and generally has less jitter?

John

On a sunny day (Sun, 10 May 2009 11:23:54 -0700) it happened John Larkin wrote in :

Oh, yes, almost all true. Obsolete? PIC has been around as long as any other suff, in more variants. So you included trimpots too? Hope you are not still using those papper caps ;-)

On a sunny day (Sun, 10 May 2009 20:21:03 +0200) it happened Marco Trapanese wrote in :

No, but you could add some 74HC [D]flops for that part.

Still no caps and resistors.

What's the lifetime of a given PIC chip? Variants don't help much if you have to re-do everything when a chip goes EOL.

If adjustable delays are useful, maybe so. How do you change or adjust the delays on an embedded PIC?

I just finished this:

It can store lists of delay and width settings, and advance to the next set every trigger. So it does delay hops, sweeps, patterns, stuff like that.

John

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

I use that part often, nice non retriggable dual one shot.

Cheers

On a sunny day (Sun, 10 May 2009 12:13:45 -0700) it happened John Larkin wrote in :

In my experience pic compatibility is really good. Even beyond PICs generations, I have used a PIC to replace dedicated chips.

If the PIC has EEPROM, RS232: just bring out one pin for Rx at TTL level, it only has to listen, you can of course bring out the TX too, and read status.

Bit of overkill for this application :-)

Woodstock: Let us do the hop - remember that ? -

No paper caps! But it does have some NTC ceramic caps, to tune the TC of an LC oscillator. They are very hard to buy in surface mount in sane quantities.

John

Has anyone made paper caps in the last 20 years?

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