Jonathan Kirwan wrote:
I don't think intel ever used PIC in relation to the 8748
It was called the MCS-48, and a Microcontroller.

Dead as in no longer made, yes.
Dead as in cannot buy it, no - I see jameco have > 1000 on the shelf,
for $3.71 each!! Others have it too.

Of course, these days, you'd use a CPLD to do the same task.
I think the 8243 did have a nice dual-edge scheme (so would need a
better CPLD), and also AND/OR access (to avoid sticky-bit issues) and
the 8748 supported it well.

-jg

On Sun, 11 Feb 2007 13:13:51 +1300, Jim Granville
<no.spam@designtools.maps.co.nz> wrote:

Spendy.

Reason I'm asking is that it would actually _work_ with a primitive
use of the parallel port on PCs, as a way of expanding it's ability to
control I/O lines and for sinking capability (5mA on all 16 pins at
the same time.) Of course, parallel ports are going away, too. Oh,
well. I suppose, sine the max delay was about 700ns or so, that a
micro using an internal RC osc could kind of double for it in many
circumstances and possibly for less than $3.71 (24 pins do cost money,
though.)

Thanks,
Jon

Jonathan Kirwan wrote:

Nope, it's what the new law forces them to do.
A classic case of where un-leashed lawyers can cost a company sales
and good will, whilst they are doing what they are supposed to do, which
is protect the companies trademarks.
If something passes into general use, then it is not trademarked.

With something like PIC, it hardly seems worth the bother!!.

-jg

On Sun, 11 Feb 2007 13:34:08 +1300, Jim Granville
<no.spam@designtools.maps.co.nz> wrote:

I'm aware of the idea that if a company doesn't work to aggressively
protect trademarks, that they lose the right to enforce them on
others.

Perhaps. But you'd think that intelligent people are in charge and
can tell the attorneys what to pursue and what not to pursue.

Yes, that much I understand.

It does.

I'm still not sure if Intel's use was considered infringing. There is
no question in my mind that Intel used the term, PIC. You didn't
address this, either. Is it? Or not? If not, doesn't that block
Microchip's right to enforce it? I'm confused about this.

Jon

On Sat, 10 Feb 2007 15:58:46 -0700, Donald <Donald@dontdoithere.com>
wrote:

Nah, not really. Interesting to learn about the history of PIC. My
apologies that I asked for an Intel 8748/49 PIC and not a simple µC.

Thanks, I got that. I´d be a newbie in developing any microcontroller
code at all. It´s really the case that I am stuck with a garage door
opener which just failed and which was installed into my garage back
in 1990.

I see. Well, I´m not yet decided how much effort and/or money I am
going to invest into the garage door opener just to get it going
again. On the other hand, the garage door opener´s hardware itself is
really rock-solid. Thus, I will definitely not be decided before I
will have exchanged the PCB´s capacitors first, just to see whether
they are the culprit ones on my defective PCB.

Thanks, got that now.

I know. *sigh* Even I studied computer science back in 1995, I was
never in charge of having to do any code development for
microcontrollers at all. So this is my first time to having to make up
my mind about µCs, especially about 8748/8749 ones.

Thanks for your kind offer. I´ll get back to it when I´ll be decided
to take the adventure to start developing own µC code for an alternate
microcontroller for my garage door opener.

Right. Or to simply skip the use of any microcontroller at all and to
realize an alternate control PCB which is mostly based on
contactors/relais like they are still widely used in elevator control
systems. *g* Ok, but I didn´t intend to get any offtopic here.

Kind regards,
Joachim

On Sun, 11 Feb 2007 12:58:17 +1300, Jim Granville
<no.spam@designtools.maps.co.nz> wrote:

Right. And thanks a lot. I really highly appreciate your quick reply.
I´m sorry I didn´t find any more time before the weekend to continue
reading all replies. My apologies.

Jonathan Kirwan wrote:

Of course; - a much more sensible approach would be to see
that any users acknowledge that it is a tm of Microchip, and even
say 'used with permission of..' - but now Microchip are now a 'billion
dollar company', so they get the billion dollar mindset, especially in
the legal dept, and one gets the impression the lawyers are running the
place.

Not a good look, for a tech company, and bad for long term business.

What intel did 25 yrs ago does not bother today's lawyers.
So long as they bang off a few cheap letters, then can say they are
currently protecting the trademark

The only thing that would block 'Microchip's right to enforce it',
would be for someone to take the considerable expense to argue that in
court, and win.

-jg

On Sat, 10 Feb 2007 13:18:50 +1300, Jim Granville
<no.spam@designtools.maps.co.nz> wrote:

Well, the IC is a 16-pin component. I currently don´t have any more
than a meter with a built-in logic tester. While the PCB is resting
silently in front of me and is connected to +12V (and to +5V via a
voltage regulator on the PCB) the 16-pin IC shows up with the
following readings:

Pin 1: Low , 0.000 kHz, 0.231 V
Pin 2: Low , 0.000 kHz, 0.167 V
Pin 3: Low , 0.000 kHz, 0.230 V
Pin 4: ----, 0.050 kHz, 3.468 V
Pin 5: High, 0.000 kHz, 4.979 V
Pin 6: High, 0.000 kHz, 4.979 V
Pin 7: Low , 0.000 kHz, 0.202 V
Pin 8: Vss (GND)
Pin 9: Low , 0.000 kHz, 0.204 V
Pin 10: High, 0.111 kHz, 4.971 V (frequency slightly alternating
around this frequency of 0.111 kHz)
Pin 11: Low , 0.000 kHz, 0.012 V
Pin 12: Low , 0.000 kHz, 0.012 V
Pin 13: ----, 0.000 kHz, 3.335 V
Pin 14: High, ?.??? kHz, 4.987 V (frequency randomly alternating from
0.000 kHz to more than 2 MHz)
Pin 15: Low , 0.000 kHz, 0.000 V
Pin 16: High, 0.000 kHz, 4.984 V

PCB front side:
http://img184.imageshack.us/img184/3231/cimg0083kj3.jpg

PCB back side:
http://img187.imageshack.us/img187/1555/cimg0084qg6.jpg

I hope not to become any offtopic. If so, please apologize and simply
ignore.

Thanks and kind regards,
Joachim

Joachim Wunder wrote:

I had a simular problem with a burned out transistor in a garage door
opener. ( controlled that light with a relay)
I could not find a transitor that would work in the circuit.
I guessed that the rest of the circuit was also burned out.

So I ended up buying another unit.

( Wife got tired of me fooling with it, no sense of adventure ;-)

donald

Joachim Wunder wrote:

Perhaps the Philips PCA8574 ?

On Sun, 11 Feb 2007 16:55:35 +1300, Jim Granville
<no.spam@designtools.maps.co.nz> wrote:

Good question. Could it even be the case to be a PAL, i.e. a
Programmable Array Logic?

Joachim Wunder wrote:
No, I know of no 16 pin SPLDs, but the 82S123 (bipolar PROM) comes in
16 pins, and we have use those as PALs many years ago.

One clue is how warm it gets

-jg

Spehro Pefhany wrote:
Circa 1980, Intel introduced HMOS including an upgraded HMOS 8x49/39 and
*some* variants of 8x48. Intel referred to their microcontroller
families as MCS, not PIC. I consider MCS-48 an abomination compared to
MCS-51 which succeeded it.

I have some used 8748s, plus one of those cool ceramic bond-out versions
with machined sockets to piggy-back a standard (2716?) EPROM. (That is
to say, "standard" as of 30 years ago!) I think the piggy-back version
cost several hundred U$D back in the 1970s. I also have a "1981 MCS-48
User's Manual" and other related "ancient" items.

I am located in the USA. If you are unable find any locally, Joachim, I
would be willing to part with any/all of these treasured antiquities.

Regards,
Steve Hoyt

--
Hoyt Engineering
http://www.HoytEngineering.com

On Mon, 12 Feb 2007 15:09:30 -0600, Steve Hoyt
<Info@HoytEngineering.com> wrote:

Thanks a mil, Steve. I will see what I can still get here in Germany.
And I may come back to your kind offer.

Thanks,
Joachim

On Fri, 09 Feb 2007 14:59:10 +1300, Jim Granville
<no.spam@designtools.maps.co.nz> wrote:

Well, a German guy just gave me the hint that the 80(C)48/80(C)49 are
pin and opcode compatible. I just started to check for pin
compatibility and it really seems to me that they are pin compatible.
Can anyone here please give his or her experience when it comes to
opcode compatibility? I know that the 80(C)48/80(C)49 are equipped
with a PROM only and not with an EPROM. But that´ll not be a problem
for me.

TIA,
Joachim

On Wed, 14 Feb 2007 01:31:50 +0100, Joachim Wunder
<Joachim_Wunder@CompuServe.COM> wrote:

I forgot to mention: The 80(C)48/80(C)49 are from OKI Semiconductor.

Joachim Wunder wrote:

The 8748 and 80C48 bith use the MCS-48 instruction set.

I thought you were trying to fix a garage door opener ?
- The 80C48/80C49 are mask ROM versions, so have MOQs of some thousands.
The 80C35/39 were the external memory model, tho the 80C48 can be
used in romless mode with external memory (latch+flash), which costs
many package pins.

- but you'll need to get the code somehow first, and the original chip
may be damaged...

-jg

On Feb 13, 4:31 pm, Joachim Wunder <Joachim_Wun...@CompuServe.COM>
wrote:
The -only- difference between the 8x48 and the 8x49 is the amount of
memory.

The -only- difference between the 878x and the 804x is the type of
memory.

The 804x does have an 'EA' pin, which will cause it to use external
memory.

Email me. I have a small stack of 8748's somewhere.

G.

On 14 Feb 2007 20:44:54 -0800, ghelbig@lycos.com wrote:

Thanks for your kind offer. Currently, the small company who
manufactured the garage door opener are still searching in their
archive for already programmed 8748/49 for me. My garage door opener
was installed 17 years ago. So, this may still need some time. I can´t
hurry things up, but I will keep you all posted.

Kind regards,
Joachim