[N8VEM: 18538] N8VEM Analog/Digital I/O board

Discussion:

Richard Cini

2014-08-13 01:47:56 UTC

All â¹

IÂ¹ve designed an analog/digital I/O board for my SBC-188 computer. IÂ¹ve
attached a PDF of the schematics for the group to look at and poke holes in
the design. The specs include an 8-input/8-bit analog input port, a single
8-bit analog output port and a single 82C55 I/O chip with all three ports
available.

IÂ¹ve attached the schematic PDF. I would greatly appreciate it if someone
could take a look at it and see if thereÂ¹s anything obviously wrong with it.
If not, IÂ¹ll prototype it and see if it actually works :-)

Thanks!

Rich

--
Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator
http://www.classiccmp.org/cini
http://www.classiccmp.org/altair32

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Vince Mulhollon

2014-08-13 11:48:23 UTC

Permalink

The specs include an 8-input/8-bit analog input port, a single 8-bit
analog output port and a single 82C55 I/O chip with all three ports
available.

Note that to "speak arduino" at least Arduino uno pinout, you only need 14
digital IO and 6 A/D inputs and +5, so you're all good there. Then you
could plug in one of about 300 or so different COTS shields as a
daughterboard. Not quite all because there are other pins but this would
run "most". Most shields are not terribly arduino-specific, like "ground
digital I/O pin 2 to turn on the optoisolated motor H bridge" or whatever.
So you can guess what I'll be doing with it if all goes well and you go
into production mode and I buy a couple. In my infinite spare time.

The odds of arduino-pinout fitting on the card are probably slight, but if
its possible when laying out the PCB... Just two rows of precision spaced
SIP female headers is all you need for most shields. The analogs go to one
header and the digitals to the other, at a certain spacing and alignment
from each other, is all it takes. Just saying...

Andrew Bingham

2014-08-13 17:08:29 UTC

Permalink

I've been thinking of doing this for a while. It would be fun to interface
the N8VEM hardware with the "real world". You could even make a robot....

Andrew B

All â
Iâve designed an analog/digital I/O board for my SBC-188 computer. Iâve
attached a PDF of the schematics for the group to look at and poke holes in
the design. The specs include an 8-input/8-bit analog input port, a single
8-bit analog output port and a single 82C55 I/O chip with all three ports
available.
Iâve attached the schematic PDF. I would greatly appreciate it if someone
could take a look at it and see if thereâs anything obviously wrong with
it. If not, Iâll prototype it and see if it actually works :-)
Thanks!
Rich
--
Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator
http://www.classiccmp.org/cini
http://www.classiccmp.org/altair32

Richard Cini

2014-08-13 17:20:53 UTC

Permalink

There is some spare board real-estate (i.e., the board isnÂ¹t particularly
dense). Anything else you think I should put on it?

Rich

--
Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator
http://www.classiccmp.org/cini
http://www.classiccmp.org/altair32

From: Andrew Bingham <abingham-***@public.gmane.org>
Reply-To: N8VEM-Post <n8vem-/***@public.gmane.org>
Date: Wednesday, August 13, 2014 at 1:08 PM
To: N8VEM-Post <n8vem-/***@public.gmane.org>
Subject: [N8VEM: 18546] Re: N8VEM Analog/Digital I/O board

I've been thinking of doing this for a while. It would be fun to interface
the N8VEM hardware with the "real world". You could even make a robot....

Andrew B

Post by Richard Cini
All â¹
IÂ¹ve designed an analog/digital I/O board for my SBC-188 computer. IÂ¹ve
attached a PDF of the schematics for the group to look at and poke holes in
the design. The specs include an 8-input/8-bit analog input port, a single
8-bit analog output port and a single 82C55 I/O chip with all three ports
available.
IÂ¹ve attached the schematic PDF. I would greatly appreciate it if someone
could take a look at it and see if thereÂ¹s anything obviously wrong with it.
If not, IÂ¹ll prototype it and see if it actually works :-)
Thanks!
Rich
--
Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator
http://www.classiccmp.org/cini
http://www.classiccmp.org/altair32

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Andrew Bingham

2014-08-13 17:27:20 UTC

Permalink

The only other thing I could think of would be a spot for something
like http://www.digikey.com/product-detail/en/AD594AQ/AD594AQ-ND/612068 and
jumpers to connect its 10mv/degC output into the input of one of the ADCs.
Then if desired, the person building the board could populate in those
ICs and read out thermocouples. I'd put a couple spots of those if there
is space. Ideally they would be by the top edge of the card so the
thermocouple can connect close by.

Andrew

There is some spare board real-estate (i.e., the board isnât particularly
dense). Anything else you think I should put on it?
Rich
--
Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator
http://www.classiccmp.org/cini
http://www.classiccmp.org/altair32
Date: Wednesday, August 13, 2014 at 1:08 PM
Subject: [N8VEM: 18546] Re: N8VEM Analog/Digital I/O board
I've been thinking of doing this for a while. It would be fun to
interface the N8VEM hardware with the "real world". You could even make a
robot....
Andrew B

--
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Andrew Bingham

2014-08-13 17:34:04 UTC

Permalink

Example of using the AD594/AD595
- http://hobbybotics.com/projects/hobbybotics-ad595-thermocouple-breakout-v1-0/

The only other thing I could think of would be a spot for something like
http://www.digikey.com/product-detail/en/AD594AQ/AD594AQ-ND/612068 and
jumpers to connect its 10mv/degC output into the input of one of the ADCs.
Then if desired, the person building the board could populate in those
ICs and read out thermocouples. I'd put a couple spots of those if there
is space. Ideally they would be by the top edge of the card so the
thermocouple can connect close by.
Andrew

All â
Iâve designed an analog/digital I/O board for my SBC-188 computer. Iâve
attached a PDF of the schematics for the group to look at and poke holes in
the design. The specs include an 8-input/8-bit analog input port, a single
8-bit analog output port and a single 82C55 I/O chip with all three ports
available.
Iâve attached the schematic PDF. I would greatly appreciate it if
someone could take a look at it and see if thereâs anything obviously wrong
with it. If not, Iâll prototype it and see if it actually works :-)
Thanks!
Rich
--
Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator
http://www.classiccmp.org/cini
http://www.classiccmp.org/altair32

Richard Cini

2014-08-13 17:44:05 UTC

Permalink

Wow, thatÂ¹s super easy. How about the board connector to the probe?

Rich

--
Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator
http://www.classiccmp.org/cini
http://www.classiccmp.org/altair32

From: Andrew Bingham <abingham-***@public.gmane.org>
Reply-To: N8VEM-Post <n8vem-/***@public.gmane.org>
Date: Wednesday, August 13, 2014 at 1:34 PM
To: N8VEM-Post <n8vem-/***@public.gmane.org>
Subject: Re: [N8VEM: 18550] Re: N8VEM Analog/Digital I/O board

Example of using the AD594/AD595 -
http://hobbybotics.com/projects/hobbybotics-ad595-thermocouple-breakout-v1-0
/

The only other thing I could think of would be a spot for something like
http://www.digikey.com/product-detail/en/AD594AQ/AD594AQ-ND/612068 and jumpers
to connect its 10mv/degC output into the input of one of the ADCs. Then if
desired, the person building the board could populate in those ICs and read
out thermocouples. I'd put a couple spots of those if there is space.
Ideally they would be by the top edge of the card so the thermocouple can
connect close by.
Andrew

Post by Richard Cini
There is some spare board real-estate (i.e., the board isnÂ¹t particularly
dense). Anything else you think I should put on it?
Rich
--
Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator
http://www.classiccmp.org/cini
http://www.classiccmp.org/altair32
Date: Wednesday, August 13, 2014 at 1:08 PM
Subject: [N8VEM: 18546] Re: N8VEM Analog/Digital I/O board
I've been thinking of doing this for a while. It would be fun to interface
the N8VEM hardware with the "real world". You could even make a robot....
Andrew B

--
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Andrew Bingham

2014-08-13 20:10:47 UTC

Permalink

You want where the probe connection to the copper to be as close to the
temperature of the IC as possible so the cold junction compensation works.
That's why the person in the Hobbybotics example used a screw terminal
connector right next to the IC. I'd tend to do the same thing.

Andrew

Wow, thatâs super easy. How about the board connector to the probe?
Rich
--
Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator
http://www.classiccmp.org/cini
http://www.classiccmp.org/altair32
Date: Wednesday, August 13, 2014 at 1:34 PM
Subject: Re: [N8VEM: 18550] Re: N8VEM Analog/Digital I/O board
Example of using the AD594/AD595 -
http://hobbybotics.com/projects/hobbybotics-ad595-thermocouple-breakout-v1-0/

The only other thing I could think of would be a spot for something like
http://www.digikey.com/product-detail/en/AD594AQ/AD594AQ-ND/612068 and
jumpers to connect its 10mv/degC output into the input of one of the ADCs.
Then if desired, the person building the board could populate in those
ICs and read out thermocouples. I'd put a couple spots of those if there
is space. Ideally they would be by the top edge of the card so the
thermocouple can connect close by.
Andrew

There is some spare board real-estate (i.e., the board isnât
particularly dense). Anything else you think I should put on it?
Rich
--
Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator
http://www.classiccmp.org/cini
http://www.classiccmp.org/altair32
Date: Wednesday, August 13, 2014 at 1:08 PM
Subject: [N8VEM: 18546] Re: N8VEM Analog/Digital I/O board
I've been thinking of doing this for a while. It would be fun to
interface the N8VEM hardware with the "real world". You could even make a
robot....
Andrew B

All â
Iâve designed an analog/digital I/O board for my SBC-188 computer. Iâve
attached a PDF of the schematics for the group to look at and poke holes in
the design. The specs include an 8-input/8-bit analog input port, a single
8-bit analog output port and a single 82C55 I/O chip with all three ports
available.
Iâve attached the schematic PDF. I would greatly appreciate it if
someone could take a look at it and see if thereâs anything obviously wrong
with it. If not, Iâll prototype it and see if it actually works :-)
Thanks!
Rich
--
Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator
http://www.classiccmp.org/cini
http://www.classiccmp.org/altair32

--
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Groups "N8VEM" group.
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Richard Cini

2014-08-14 18:35:42 UTC

Permalink

All â¹

OK, attached is the revised schematic, including two thermocouple channels.
IÂ¹ve also included the board plot (top only) which doesnÂ¹t include the
pours. There will be two pour zones, one on the analog side and one on the
digital size, tied to the single-point ground. Have a look and if it looks
good, I may order a few prototype boards for testing purposes.

Thanks!

Rich

--
Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator
http://www.classiccmp.org/cini
http://www.classiccmp.org/altair32

From: Andrew Bingham <abingham-***@public.gmane.org>
Reply-To: N8VEM-Post <n8vem-/***@public.gmane.org>
Date: Wednesday, August 13, 2014 at 4:10 PM
To: N8VEM-Post <n8vem-/***@public.gmane.org>
Subject: Re: [N8VEM: 18552] Re: N8VEM Analog/Digital I/O board

You want where the probe connection to the copper to be as close to the
temperature of the IC as possible so the cold junction compensation works.
That's why the person in the Hobbybotics example used a screw terminal
connector right next to the IC. I'd tend to do the same thing.

Andrew

Post by Richard Cini
Wow, thatÂ¹s super easy. How about the board connector to the probe?
Rich
--
Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator
http://www.classiccmp.org/cini
http://www.classiccmp.org/altair32
Date: Wednesday, August 13, 2014 at 1:34 PM
Subject: Re: [N8VEM: 18550] Re: N8VEM Analog/Digital I/O board
Example of using the AD594/AD595 -
http://hobbybotics.com/projects/hobbybotics-ad595-thermocouple-breakout-v1-0/

The only other thing I could think of would be a spot for something like
http://www.digikey.com/product-detail/en/AD594AQ/AD594AQ-ND/612068 and
jumpers to connect its 10mv/degC output into the input of one of the ADCs.
Then if desired, the person building the board could populate in those ICs
and read out thermocouples. I'd put a couple spots of those if there is
space. Ideally they would be by the top edge of the card so the thermocouple
can connect close by.
Andrew

Post by Richard Cini
All â¹
IÂ¹ve designed an analog/digital I/O board for my SBC-188 computer. IÂ¹ve
attached a PDF of the schematics for the group to look at and poke holes in
the design. The specs include an 8-input/8-bit analog input port, a single
8-bit analog output port and a single 82C55 I/O chip with all three ports
available.
IÂ¹ve attached the schematic PDF. I would greatly appreciate it if someone
could take a look at it and see if thereÂ¹s anything obviously wrong with
it. If not, IÂ¹ll prototype it and see if it actually works :-)
Thanks!
Rich
--
Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator
http://www.classiccmp.org/cini
http://www.classiccmp.org/altair32

--
You received this message because you are subscribed to the Google Groups
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Visit this group at http://groups.google.com/group/n8vem.
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Andrew Bingham

2014-08-13 20:24:36 UTC

Permalink

There is a "newer" surface mount version that is much cheaper ($5-$8 vs
$17) -
http://www.analog.com/static/imported-files/data_sheets/AD8494_8495_8496_8497.pdf.
We don't use surface mount on most of the N8VEM boards though....

The only other thing I could think of would be a spot for something like
http://www.digikey.com/product-detail/en/AD594AQ/AD594AQ-ND/612068 and
jumpers to connect its 10mv/degC output into the input of one of the ADCs.
Then if desired, the person building the board could populate in those
ICs and read out thermocouples. I'd put a couple spots of those if there
is space. Ideally they would be by the top edge of the card so the
thermocouple can connect close by.
Andrew

There is some spare board real-estate (i.e., the board isnât
particularly dense). Anything else you think I should put on it?
Rich
--
Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator
http://www.classiccmp.org/cini
http://www.classiccmp.org/altair32
Date: Wednesday, August 13, 2014 at 1:08 PM
Subject: [N8VEM: 18546] Re: N8VEM Analog/Digital I/O board
I've been thinking of doing this for a while. It would be fun to
interface the N8VEM hardware with the "real world". You could even make a
robot....
Andrew B

All â
Iâve designed an analog/digital I/O board for my SBC-188 computer. Iâve
attached a PDF of the schematics for the group to look at and poke holes in
the design. The specs include an 8-input/8-bit analog input port, a single
8-bit analog output port and a single 82C55 I/O chip with all three ports
available.
Iâve attached the schematic PDF. I would greatly appreciate it if
someone could take a look at it and see if thereâs anything obviously wrong
with it. If not, Iâll prototype it and see if it actually works :-)
Thanks!
Rich
--
Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator
http://www.classiccmp.org/cini
http://www.classiccmp.org/altair32

Vince Mulhollon

2014-08-13 20:38:41 UTC

Permalink

Post by Andrew Bingham
There is a "newer" surface mount version that is much cheaper ($5-$8 vs
$17) -
http://www.analog.com/static/imported-files/data_sheets/AD8494_8495_8496_8497.pdf
<http://www.google.com/url?q=http%3A%2F%2Fwww.analog.com%2Fstatic%2Fimported-files%2Fdata_sheets%2FAD8494_8495_8496_8497.pdf&sa=D&sntz=1&usg=AFQjCNFR4jflYI5Yfn8lzcnCEvD_-9lkOQ>.
We don't use surface mount on most of the N8VEM boards though....

Would it work out topologically to have pads for both the SMD and the DIP
in parallel, just don't solder both in? Like the SMD on the solder side
and the DIP on the package side, so both are close to the cold junction?

I find it easier/faster to solder SMD than thru hole, and I get to save
$12, so I know which I'll solder in, but the thru hole would be available
for people who want it, so everyone would be pretty happy.