It's in an old (mid-80's) industrial machine. The French mfr. is out of
business. The circuit I'm trying to resurrect takes a digital measuring
encoder as input and displays the measurement on 7-segment LED displays.
Display went wonky for a few weeks, then went blank, entirely. DC voltages
and ripple are all good. Tried reseating socketed components; no joy.

Lacking any documentation, I'm going to try some "shotgun" troubleshooting by
replacing the major components on the board (they're socketed).

Large components include:
D8085AHC
D8155HC
D8279C-2
uPB8212C
All parts NEC mfr.

When replacing with components available today, what are my limitations? (For
example, I know "H" means HMOS, and that is a "must".) What else should I be
careful re. the letter digits of the p/n's when selecting parts with the same
numerical digits of the p/n's?

I know that the 8279 is a programmable controller, so replacing that without
having the source code to program it with, is out of the question.

Just trying to help a client keep this otherwise good machine in service and
avoid "binning" it.

Thanks,
--
DaveC

This is an invalid return address
Please reply in the news group

http://www.csee.umbc.edu/~plusquel/3...8086_IO3.html\

looks like the 8279 has an internal OTP EPROM.

Might be tough to find a replacement

Bill

www.myblueroom.com

Thus spake William at MyBlueRoom:

http://www.csee.umbc.edu/~plusquel/3...8086_IO3.html\

looks like the 8279 has an internal OTP EPROM.

This is what I need help determining. If this is a "production programmed"
device (burned at time of manufacture), it's a deal-killer for my customer --
finding a programmed replacement is pretty much not going to happen.

But if this is a "dynamically programmed" device (ie, counters are loaded at
run time and reset by external devices), I presume that off-the-shelf it will
replace the suspect one in the machine.

Is the 8279 a one-time programmed device?

Thanks,
--
DaveC

This is an invalid return address
Please reply in the news group

DaveC wrote:

Thus spake William at MyBlueRoom:

http://www.csee.umbc.edu/~plusquel/3...8086_IO3.html\

looks like the 8279 has an internal OTP EPROM.

This is what I need help determining. If this is a "production programmed"
device (burned at time of manufacture), it's a deal-killer for my customer --
finding a programmed replacement is pretty much not going to happen.

It appears not to be.

http://www.csee.umbc.edu/~plusquel/3.../8086_IO3.html

Graham

On Fri, 24 Feb 2006 11:05:27 -0800, DaveC wrote:

It's in an old (mid-80's) industrial machine. The French mfr. is out of
business. The circuit I'm trying to resurrect takes a digital measuring
encoder as input and displays the measurement on 7-segment LED displays.
Display went wonky for a few weeks, then went blank, entirely. DC voltages
and ripple are all good. Tried reseating socketed components; no joy.

Lacking any documentation, I'm going to try some "shotgun" troubleshooting by
replacing the major components on the board (they're socketed).

Large components include:
D8085AHC
D8155HC
D8279C-2
uPB8212C
All parts NEC mfr.

When replacing with components available today, what are my limitations? (For
example, I know "H" means HMOS, and that is a "must".) What else should I be
careful re. the letter digits of the p/n's when selecting parts with the same
numerical digits of the p/n's?

I know that the 8279 is a programmable controller, so replacing that without
having the source code to program it with, is out of the question.

Just trying to help a client keep this otherwise good machine in service and
avoid "binning" it.

Thanks,

Hi,

All those parts are still available in the market.

Pieter

DaveC wrote:


Is the 8279 a one-time programmed device?

No, it is just a peripheral with some registers to 'program' its function.

"Pooh Bear" wrote in message
...


DaveC wrote:

Thus spake William at MyBlueRoom:

http://www.csee.umbc.edu/~plusquel/3...8086_IO3.html\

looks like the 8279 has an internal OTP EPROM.

This is what I need help determining. If this is a "production
programmed"
device (burned at time of manufacture), it's a deal-killer for my
customer --
finding a programmed replacement is pretty much not going to happen.

It appears not to be.

http://www.csee.umbc.edu/~plusquel/3.../8086_IO3.html

Graham


It seems to me that everyone is "going off on one", before the OP has
applied at least basic proper fault finding techniques. Before going in
shotgun and replacing parts that - trust me - seldom if ever go faulty, you
should first check that the 5v supply is absolutely good - voltage, ripple
AND noise, that the reset generator is working correctly, and that most
importantly, the system clock generator is running, and producing a correct
amplitude and frequency, signal. Also that any following clock distribution
buffers are working.

If none of those checks turn up the problem, and in at least 80% of cases on
this old simple logic, they will, then the next move is to download a
datasheet for the display controller, and figure why it's not driving the
displays. The required inputs are not many, and not complex, and require
only a 'scope to verify.

From years of experience repairing electronic equipment, I can tell you that
blanket replacement of components in the fond hope of hitting the right one,
is about the worst approach that you can take, and likely to result in more
problems than the probably simple one that you had in the first place.

Arfa

It sounds as though the instrument is a Digital Readout display
associated with machining or other production equipment.
I don't have much advice for troubleshooting other than what's already
been suggested by Arfa.
It's been too many years, and too little practice since my training in
these types of circuits. I have a completely dead Anilam DRO display,
and I've had difficulty understanding the circuits even though I have a
schematic.

If you proceed with IC replacement, check any datasheets you can find
to confirm that the operating voltages of replacement parts are the
same.

Newer used DRO systems are plentiful, depending upon your searching
abilities. If the linear encoder scales used with the DRO display unit
are the commly used 5 volt TTL squarewave types, you could possibly
just replace the display unit with one that's compatible.

Finding a suitable replacement will probably be a little tougher if the
DRO display also has outputs for interfacing with NC or CNC machine
controls, but numerous displays have various optional modules to
convert inputs to outputs.

There are numerous surplus suppliers of older ICs in the U.S, and more
semiconductor sellers are gradually appearing on eBay.

Cheers
WB
...............

DaveC wrote:
It's in an old (mid-80's) industrial machine. The French mfr. is out of
business. The circuit I'm trying to resurrect takes a digital measuring
encoder as input and displays the measurement on 7-segment LED displays.
Display went wonky for a few weeks, then went blank, entirely. DC voltages
and ripple are all good. Tried reseating socketed components; no joy.

Lacking any documentation, I'm going to try some "shotgun" troubleshooting by
replacing the major components on the board (they're socketed).

Large components include:
D8085AHC
D8155HC
D8279C-2
uPB8212C
All parts NEC mfr.

When replacing with components available today, what are my limitations? (For
example, I know "H" means HMOS, and that is a "must".) What else should I be
careful re. the letter digits of the p/n's when selecting parts with the same
numerical digits of the p/n's?

I know that the 8279 is a programmable controller, so replacing that without
having the source code to program it with, is out of the question.

Just trying to help a client keep this otherwise good machine in service and
avoid "binning" it.

Thanks,
--
DaveC

This is an invalid return address
Please reply in the news group

linnix wrote:

Perhaps the local fea market. Look for old 8 bits micros. The 8085
is an old 8 bits micro, so there must be an EPROM somewhere.
Unfortunately, EPROM data are not designed to last for 20 years. It's
amazing to have lasted so long already. My first bet is the EPROM
losing contents. Unless you have a copy of the data somewhere, forget
it.

Reducing the supply voltage a bit (was it? or increasing?) might still
recover the data.


Thomas

On 24 Feb 2006 13:50:57 -0800, the renowned "linnix"
wrote:


Pieter wrote:
On Fri, 24 Feb 2006 11:05:27 -0800, DaveC wrote:

It's in an old (mid-80's) industrial machine. The French mfr. is out of
business. The circuit I'm trying to resurrect takes a digital measuring
encoder as input and displays the measurement on 7-segment LED displays.
Display went wonky for a few weeks, then went blank, entirely. DC voltages
and ripple are all good. Tried reseating socketed components; no joy.

Lacking any documentation, I'm going to try some "shotgun" troubleshooting by
replacing the major components on the board (they're socketed).

Large components include:
D8085AHC
D8155HC
D8279C-2
uPB8212C
All parts NEC mfr.

When replacing with components available today, what are my limitations? (For
example, I know "H" means HMOS, and that is a "must".) What else should I be
careful re. the letter digits of the p/n's when selecting parts with the same
numerical digits of the p/n's?

I know that the 8279 is a programmable controller, so replacing that without
having the source code to program it with, is out of the question.

Just trying to help a client keep this otherwise good machine in service and
avoid "binning" it.

Thanks,

Hi,

All those parts are still available in the market.

Perhaps the local fea market. Look for old 8 bits micros. The 8085
is an old 8 bits micro, so there must be an EPROM somewhere.
Unfortunately, EPROM data are not designed to last for 20 years.

Do you have any data which supports this claim?

Most manufacturers claim 100 years or more at normal temperatures.

It's amazing to have lasted so long already.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

On Sat, 25 Feb 2006 16:37:57 +0100, the renowned Zak
wrote:

linnix wrote:

Perhaps the local fea market. Look for old 8 bits micros. The 8085
is an old 8 bits micro, so there must be an EPROM somewhere.
Unfortunately, EPROM data are not designed to last for 20 years. It's
amazing to have lasted so long already. My first bet is the EPROM
losing contents. Unless you have a copy of the data somewhere, forget
it.

Reducing the supply voltage a bit (was it? or increasing?) might still
recover the data.

Yes.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

DaveC wrote:

It's in an old (mid-80's) industrial machine. The French mfr. is out of
business. The circuit I'm trying to resurrect takes a digital measuring
encoder as input and displays the measurement on 7-segment LED displays.
Display went wonky for a few weeks, then went blank, entirely. DC voltages
and ripple are all good. Tried reseating socketed components; no joy.

Lacking any documentation, I'm going to try some "shotgun" troubleshooting by
replacing the major components on the board (they're socketed).

Large components include:
D8085AHC
D8155HC
D8279C-2
uPB8212C
All parts NEC mfr.

When replacing with components available today, what are my limitations? (For
example, I know "H" means HMOS, and that is a "must".) What else should I be
careful re. the letter digits of the p/n's when selecting parts with the same
numerical digits of the p/n's?

I know that the 8279 is a programmable controller, so replacing that without
having the source code to program it with, is out of the question.

Just trying to help a client keep this otherwise good machine in service and
avoid "binning" it.

Thanks,

All of those parts were originally from INTEL. NEC was a second
source. What type of RAM does it use?

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Spehro Pefhany wrote:
Unfortunately, EPROM data are not designed to last for 20 years. It's
amazing to have lasted so long already. My first bet is the EPROM
losing contents. Unless you have a copy of the data somewhere, forget
it.

Reducing the supply voltage a bit (was it? or increasing?) might still
recover the data.
Yes.

....also had good experience with carefully cooling
the EPROMS during readout...

Erik.

...

Most manufacturers claim 100 years or more at normal temperatures.

People who made these claims in the 80s are mostly retired or dead.

Can't find any typical EPROM (2716 or 2732) used in the 80s. A newer
one like AT28C16 says data retentions of 10 years. If you want to bet
$1 per year, we can find an independent engineer for verification.


It's amazing to have lasted so long already.

...

On 24 Feb 2006 13:50:57 -0800, "linnix" wrote:


Pieter wrote:
On Fri, 24 Feb 2006 11:05:27 -0800, DaveC wrote:

It's in an old (mid-80's) industrial machine. The French mfr. is out of
business. The circuit I'm trying to resurrect takes a digital measuring
encoder as input and displays the measurement on 7-segment LED displays.
Display went wonky for a few weeks, then went blank, entirely. DC voltages
and ripple are all good. Tried reseating socketed components; no joy.

Lacking any documentation, I'm going to try some "shotgun" troubleshooting by
replacing the major components on the board (they're socketed).

Large components include:
D8085AHC
D8155HC
D8279C-2
uPB8212C
All parts NEC mfr.

When replacing with components available today, what are my limitations? (For
example, I know "H" means HMOS, and that is a "must".) What else should I be
careful re. the letter digits of the p/n's when selecting parts with the same
numerical digits of the p/n's?

I know that the 8279 is a programmable controller, so replacing that without
having the source code to program it with, is out of the question.

Just trying to help a client keep this otherwise good machine in service and
avoid "binning" it.

Thanks,

Hi,

All those parts are still available in the market.

Perhaps the local fea market. Look for old 8 bits micros. The 8085
is an old 8 bits micro, so there must be an EPROM somewhere.
Unfortunately, EPROM data are not designed to last for 20 years. It's
amazing to have lasted so long already. My first bet is the EPROM
losing contents. Unless you have a copy of the data somewhere, forget
it.

Sound like this is a frequency counter/display or something. A single
chip micro (AVR or PIC) can do the same.

Pieter

There are still lots of devices in older stocks available. And for
many devices replacement parts have been created by others.

I just did a quick search and found hundreds of the D8085HC of NEC at
my contacts. It is expensive to get 1 part due to the shipment costs,
but it is possible. I havent searched the other partsm, but I am
certain they are available too.

Pieter

On 24 Feb 2006 13:50:57 -0800, "linnix" wrote:


Pieter wrote:
On Fri, 24 Feb 2006 11:05:27 -0800, DaveC wrote:

It's in an old (mid-80's) industrial machine. The French mfr. is out of
business. The circuit I'm trying to resurrect takes a digital measuring
encoder as input and displays the measurement on 7-segment LED displays.
Display went wonky for a few weeks, then went blank, entirely. DC voltages
and ripple are all good. Tried reseating socketed components; no joy.

Lacking any documentation, I'm going to try some "shotgun" troubleshooting by
replacing the major components on the board (they're socketed).

Large components include:
D8085AHC
D8155HC
D8279C-2
uPB8212C
All parts NEC mfr.

When replacing with components available today, what are my limitations? (For
example, I know "H" means HMOS, and that is a "must".) What else should I be
careful re. the letter digits of the p/n's when selecting parts with the same
numerical digits of the p/n's?

I know that the 8279 is a programmable controller, so replacing that without
having the source code to program it with, is out of the question.

Just trying to help a client keep this otherwise good machine in service and
avoid "binning" it.

Thanks,

Hi,

All those parts are still available in the market.

Perhaps the local fea market. Look for old 8 bits micros. The 8085
is an old 8 bits micro, so there must be an EPROM somewhere.
Unfortunately, EPROM data are not designed to last for 20 years. It's
amazing to have lasted so long already. My first bet is the EPROM
losing contents. Unless you have a copy of the data somewhere, forget
it.

Sound like this is a frequency counter/display or something. A single
chip micro (AVR or PIC) can do the same.

Pieter

Hi, in the old days, things had to live much longer. Some eproms were
specified for 10 years, but a lot for 100 years. Compare that to
nowadays electronics.

It also depends on how well the eprom was programmed, with the "speed"
options of several programmers, the small eprom-capacitors may not
have been charged to their full capacity but only a little above the
"ok" limit. I can imagine that they loose their contents faster.

Pieter

"Pieter" wrote in message
news
On 24 Feb 2006 13:50:57 -0800, "linnix" wrote:


Pieter wrote:
On Fri, 24 Feb 2006 11:05:27 -0800, DaveC wrote:

It's in an old (mid-80's) industrial machine. The French mfr. is out
of
business. The circuit I'm trying to resurrect takes a digital
measuring
encoder as input and displays the measurement on 7-segment LED
displays.
Display went wonky for a few weeks, then went blank, entirely. DC
voltages
and ripple are all good. Tried reseating socketed components; no joy.

Lacking any documentation, I'm going to try some "shotgun"
troubleshooting by
replacing the major components on the board (they're socketed).

Large components include:
D8085AHC
D8155HC
D8279C-2
uPB8212C
All parts NEC mfr.

When replacing with components available today, what are my
limitations? (For
example, I know "H" means HMOS, and that is a "must".) What else
should I be
careful re. the letter digits of the p/n's when selecting parts with
the same
numerical digits of the p/n's?

I know that the 8279 is a programmable controller, so replacing that
without
having the source code to program it with, is out of the question.

Wrong, the 8279 is a programmable floppy controller which means it is a
floppy controller you can program to read different formats. It is
"programmed" by the code that executes on the 8085. There is no code inside
the 8279.

Meindert

Every one of those is available as Intel, TI, or NEC, and maybe
others. They were very common components and turn up all the time.
You can get tubes of them on Ebay cheap, and a google search should
turn up sources for all of them.




DaveC wrote:
It's in an old (mid-80's) industrial machine. The French mfr. is out of
business. The circuit I'm trying to resurrect takes a digital measuring
encoder as input and displays the measurement on 7-segment LED displays.
Display went wonky for a few weeks, then went blank, entirely. DC voltages
and ripple are all good. Tried reseating socketed components; no joy.

Lacking any documentation, I'm going to try some "shotgun" troubleshooting by
replacing the major components on the board (they're socketed).

Large components include:
D8085AHC
D8155HC
D8279C-2
uPB8212C
All parts NEC mfr.

"Arfa Daily" wrote in message
...
From years of experience repairing electronic equipment, I can tell you
that blanket replacement of components in the fond hope of hitting the
right one, is about the worst approach that you can take, and likely to
result in more problems than the probably simple one that you had in the
first place.

Arfa

I have to agree with the above. Its shocking how quickly an experienced
repair guy can pinpoint a problem on a completely unknown piece of
equipment-and he never ever replaces a whole bunch of parts hoping to hit
the right one. One of the first thoughts I had after reading the original
post was that the guy didn't seem to be going about the repair the right
way. Almost always the problems seem to be bad solder joints, bad caps, bad
power supply, bad component that typically runs warm/hot. There is a lot of
stuff I would check before replacing mass quantities of ICs. I worked with
a guy once who was really good at repairing electronics, for about a week, I
learned more than I ever thought possible.

--Dan

Pieter wrote:
...

Perhaps the local fea market. Look for old 8 bits micros. The 8085
is an old 8 bits micro, so there must be an EPROM somewhere.
Unfortunately, EPROM data are not designed to last for 20 years. It's
amazing to have lasted so long already. My first bet is the EPROM
losing contents. Unless you have a copy of the data somewhere, forget
it.


Hi, in the old days, things had to live much longer. Some eproms were
specified for 10 years, but a lot for 100 years. Compare that to
nowadays electronics.

It also depends on how well the eprom was programmed, with the "speed"
options of several programmers, the small eprom-capacitors may not
have been charged to their full capacity but only a little above the
"ok" limit. I can imagine that they loose their contents faster.


OK, since you are so confident about this, let each put up $100 cash.
You find the EPROM and I set up the programming and verification
environments in a third party site. Your familly get the cash if it
lasts 100 years and mine get it if not. Perhaps some one in vegas
would be willing to hosts this bet.

Meindert Sprang wrote:

Wrong, the 8279 is a programmable floppy controller which means it is a
floppy controller you can program to read different formats. It is
"programmed" by the code that executes on the 8085. There is no code inside
the 8279.

Meindert


Sorry, Meindert, but you are wrong. According to the 1990 INTEL
Peripherals Databook the 8279/8279-5 is a Programmable Keyboard /
Display interface. The datasheet is dated Sept 1987 and is on pages
3-215 to 3-230

The 8272A is a Single / Double Density Floppy Disk Controller chip.
The data sheet is in the 1990 INTEL Peripherals Databook and is dated
Nov 1986. It is on pages 4-1 to 4-31. This was used on the original IBM
PC on their floppy disk controller card. The clones used the NEC
version because it was cheaper.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

"Michael A. Terrell" wrote in message
...
Meindert Sprang wrote:

Wrong, the 8279 is a programmable floppy controller which means it is a
floppy controller you can program to read different formats. It is
"programmed" by the code that executes on the 8085. There is no code
inside
the 8279.

Meindert


Sorry, Meindert, but you are wrong. According to the 1990 INTEL
Peripherals Databook the 8279/8279-5 is a Programmable Keyboard /
Display interface. The datasheet is dated Sept 1987 and is on pages
3-215 to 3-230

The 8272A is a Single / Double Density Floppy Disk Controller chip.
The data sheet is in the 1990 INTEL Peripherals Databook and is dated
Nov 1986. It is on pages 4-1 to 4-31. This was used on the original IBM
PC on their floppy disk controller card. The clones used the NEC
version because it was cheaper.

Oops! I mixed up some numbers here.....

But then again, is there really code inside the 8279? I vaguely remember
that the SDK-85 from Intel also had this chip and that programmable only
meant that you could set it up for a variety of keymatrices and display
configurations.

Meindert

"nospam" a écrit dans le message news:
...
DaveC wrote:
Is the 8279 a one-time programmed device?
No, it is just a peripheral with some registers to 'program' its function.

Hi all
It's true. 8279 is "programmed" at the boot of the CPU by the program. It was
used to interface the keyboard.

I remember to have designed a system, at the same period, with the same
components. The board using this ICs serie was the CPU, and should contain the
eproms with the program.

I suppose the board is not a standalone, but one of the many boards the system
was made of. You should find I/O boards, probably a 7 segment LED display, push
buttons simplified keyboard, battery saved RAM...

--
Guy Pastuzak

Adresse ANTISPAM
ANTISPAM address

"Michael A. Terrell" a écrit dans le message news:
...
All of those parts were originally from INTEL. NEC was a second
source. What type of RAM does it use?

8155 contains a "small" RAM 256 bytes
Suffisant for the stack and some data.

Another saved RAM is probably located on another board

--
Guy Pastuzak

Adresse ANTISPAM
ANTISPAM address

On Sat, 25 Feb 2006 17:32:16 GMT, "Michael A. Terrell"
put finger to keyboard and composed:

DaveC wrote:

It's in an old (mid-80's) industrial machine. The French mfr. is out of
business. The circuit I'm trying to resurrect takes a digital measuring
encoder as input and displays the measurement on 7-segment LED displays.
Display went wonky for a few weeks, then went blank, entirely. DC voltages
and ripple are all good. Tried reseating socketed components; no joy.

Lacking any documentation, I'm going to try some "shotgun" troubleshooting by
replacing the major components on the board (they're socketed).

Large components include:
D8085AHC
D8155HC
D8279C-2
uPB8212C
All parts NEC mfr.

When replacing with components available today, what are my limitations? (For
example, I know "H" means HMOS, and that is a "must".) What else should I be
careful re. the letter digits of the p/n's when selecting parts with the same
numerical digits of the p/n's?

I know that the 8279 is a programmable controller, so replacing that without
having the source code to program it with, is out of the question.

Just trying to help a client keep this otherwise good machine in service and
avoid "binning" it.

Thanks,

All of those parts were originally from INTEL. NEC was a second
source. What type of RAM does it use?

The 8155 has on-chip RAM.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

On Tue, 28 Feb 2006 09:55:43 +0100, "Meindert Sprang"
wrote:

"Michael A. Terrell" wrote in message
...
Meindert Sprang wrote:

Wrong, the 8279 is a programmable floppy controller which means it is a
floppy controller you can program to read different formats. It is
"programmed" by the code that executes on the 8085. There is no code
inside
the 8279.

Meindert


Sorry, Meindert, but you are wrong. According to the 1990 INTEL
Peripherals Databook the 8279/8279-5 is a Programmable Keyboard /
Display interface. The datasheet is dated Sept 1987 and is on pages
3-215 to 3-230

The 8272A is a Single / Double Density Floppy Disk Controller chip.
The data sheet is in the 1990 INTEL Peripherals Databook and is dated
Nov 1986. It is on pages 4-1 to 4-31. This was used on the original IBM
PC on their floppy disk controller card. The clones used the NEC
version because it was cheaper.

Oops! I mixed up some numbers here.....

But then again, is there really code inside the 8279? I vaguely remember
that the SDK-85 from Intel also had this chip and that programmable only
meant that you could set it up for a variety of keymatrices and display
configurations.

Meindert


By programmable the databook means that you can change the
configuration of i/o etc with your application. Usually done at power
up. The device has NO code, your write some data in some registers.

Pieter

guy pastuzak wrote:

"Michael A. Terrell" a écrit dans le message
news: ...
All of those parts were originally from INTEL. NEC was a second
source. What type of RAM does it use?

8155 contains a "small" RAM 256 bytes
Suffisant for the stack and some data.

Another saved RAM is probably located on another board

--
Guy Pastuzak

Adresse ANTISPAM
ANTISPAM address

Actually it is a whole 2 kB.
--
JosephKK
Gegen dummheit kampfen die Gotter Selbst, vergebens.
--Schiller

guy pastuzak wrote:

"Michael A. Terrell" a écrit dans le message news:
...
All of those parts were originally from INTEL. NEC was a second
source. What type of RAM does it use?

8155 contains a "small" RAM 256 bytes
Suffisant for the stack and some data.

Another saved RAM is probably located on another board


I've never used the 8155 and don't think I have a datasheet in my
collection, so I wasn't familar with it.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

http://www2.okisemi.com/site/product...bsolete_MPUDoc

The datasheet of 8155 is available at the above as MSM81C55-5RS

Allen

http://www2.okisemi.com/site/product...bsolete_MPUDoc

The datasheet of 8155 is available at the above as MSM81C55-5RS

Allen