I2C through PC parallel port, serial port and/or USB port - please help

Under Windows NT/2000, I am interested in learning how to
program an I2C device through the following ports: parallel, serial and USB.

Is there a reasonably priced good/quality development board with
I2C device and all the ports mentioned above? Or, any other suggestions?

 

For parallel port you don't need one, the interface is dirt simple,
you can build it into the shell of a d-sub hood.

 

However, for NT/2K you will also need to use a kernel-level driver
in order to gain access to the ports. Check at <www.lvr.com>
for some notes on this. You don't need any special driver
for Win9x port access.






Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com

 

I'm a newbie so please excuse any dumb questions...

After your suggestion, I'm thinking about building my own circuitry with
a solderless breadboard. Hmmm ... would I be able to use a cable to
connect from the PC's parallel port to the breadboard? If so,
GREAT but how? It would be nice if I can use my printer cable with
the breadboard. But, I don't see how with the centronics connectors here:
http://www.cnaweb.com/en-us/dept_24.html since I don't see how they
can be used with the breadboard. Am I missing something?
Or, would I have to get another cable and use the d-sub connectors here:
http://www.cnaweb.com/en-us/dept_25.html? If so, which parts are best to use?
I need something that will work well with the breadboard.

 

Yes, that's what I thought but wasn't sure. Thanks for the confirmation and info.

 

To get to a breadboard I use this kind:
http://dkc3.digikey.com/PDF/T042/0024.pdf
Depending on what your breadboard looks like... you straddle the gutter.
I'd solder into the DB25 or centronix connector.

 

This board: http://www.i2ctools.com/hardware.htm
seems to have many of the features that I am looking for in the target circuit.
[Am I in over my head? If so, I'll just simplify it.] And,
they use a DB25M connector to plug directly into
the PC's parallel port without a cable. I guess I could use a DB25M to
DB25F extension (or whatchamacallit) cable. Searching www.digikey.com
for "cable db25m db25f" shows two such cables. I only wish that
there were images or PDFs associated with them. The price is not bad (~$8).

Or, I could use the more flexible (40-pin) cable that you mention.
But, I'm not sure I know how best to take advantage of it yet.
All the choices (single/double ended, gold/tin finish, etc.) is
confusing for a newbie. Any further suggestions much appreciated.
Also, I hope to find ways around soldering.

 

What I use to ecperiment is a ribbon cble with a 25 pin male, and a 26
socket pin connector (like is on IDE/floppy ribbon cables).

Specifically for I2C, I have a reader I built into a hood with a 6 way
ribbon out with 6 way pin socket.

 

I wasn't able to find the ribbon cable with DB25M and 26-pin socket that
you mention. But, I was able to find a ribbon cable with DB25 M-F (~$5) here:
http://www.jameco.com/Jameco/Products/ProdCT/p068.pdf
Is there a benefit of using the ribbon cable with 26-pin socket?

Whoa! You're really keeping me on my toes and making (newbie) me think.
You lost me with the I2C reader and 6-way ribbon cable stuff.
Further elaboration much appreciated.

 

On Sat, 26 Jun 2004 18:55:34 -0400, Gary Tait

He is looking for a good and easy connection to the breadboard. It depends
a bit on the layout of the breadboard of course but I have found that the
DIP type plugs work well, they have 0.1 inch X 0.3 inch or even 0.5 inch
spacing . Like chips .
What is the pin spacing on the 26pin connector you mention?

 

It's not easy to disconnect and connect, IMHO, but
I guess 0.1" straight male headers like those found here:
http://www.jameco.com/Jameco/Products/ProdCT/p077.pdf
could be used to connect the 26-pin socket connector to the breadboard.

However, if I cannot find the ribbon cable with the 26-pin socket connector,
I'll have to go with the ribbon cable with DB25 M-F from:
http://www.jameco.com/Jameco/Products/ProdCT/p068.pdf and
connect the female end to
a DB25 male right angle PC mount (short type) connector (85-728) from
http://www.cnaweb.com/en-us/dept_25.html. I'm not sure how this
approach will work with the breadboard though.

I'm thinking about a solderless breadboard something like:
http://www.montek.com/catalog/item520.htm.
Any other suggestions?

Did you say that the cables with DIP connectors require soldering?
Is there a way to work around soldering?

 

There are several linux parallel port drivers supported.

 

For simple/test projects, I just use cat3 four conductor
telephone wire for the parallel port connection. Cheap and easy.
Below are a couple of projects where I've used the four conductor
wire. You just use more wires depending on the number of
conductors you want to use to the parallel port.

http://www.geocities.com/zoomkat/ppswitcher.htm
http://www.geocities.com/zoomkat/ppswitcher2.htm
http://www.geocities.com/zoomkat/status.htm

 

The square posts of the male headers are a tight fit for the breadboard
But the problem IMHO is really that you have to span the 0.3in gap between
arrays to get all signals to the board.
The contacts on the board are thus:
11111__22222
33333__44444
55555__66666 etc.
If you stick your header into the left column then you connect odd & even
wires.
The DIP type connectors can straddle the gap between columns.

This may actually work if the right angle pins are long enough & can be
bent apart to fit the two columns above.
You'll have to do some bending anyways since the two rows are offset.
Worth trying.

This looks rather fancy & way big for what I understand you want to do.
I have one just like it.

No. The DIP connector cables I actually bought as readymade harness from
DigiKey . When the needs changed I cut it apart in the middle & put other
connectors to those ends.
I figured if you're only dealing with 6 wires or so it is (for me) quicker
to solder. If you do 25 wires that is another story.

BTW if you shop from 3 different suppliers for onesies and twosies the
shipping & handling cost is going to be brutal.


Cheers

 

Thats becuase I made i t (well, I had a 25 pin Dsub M-M cable I cut
off the one D-sub and attached the 26 pin connector to).

The sockets are standard 0.1 inches, and contact the same wire the

It is a semi custom (home built really), cable I made for programming
a certain brand of universal remote (One For All).

 

Standard 0.1" The same as an IDE or floppy cable, except 26 pins
instead of 40 or 34 for IDE/Floppy.

 

Cool! Sounds like interesting stuff. If you haven't already,
you might consider posting your work (with images) like Si Ballenger did:
http://www.geocities.com/zoomkat/ppswitcher.htm
http://www.geocities.com/zoomkat/ppswitcher2.htm
http://www.geocities.com/zoomkat/status.htm

 

Oh, I see your point about DIP type connectors now.

I think I'm going to make life easier for myself and
use hookup wires with a female header socket at one end and
male on the other end similar to the ones mentioned here:
http://www.seetron.com/lcd_an2.htm#crimp under
"Breadboard and Proto Hookup" to connect the right angle pins to
the breadboard. Anyone know where I can find these?

I found larger yet cheaper breadboards here:
http://www.elexp.com/bb_104.htm,
http://www.elexp.com/bb_sb01.htm and
http://www.elexp.com/bb_3104.htm
Not sure if there are significant differences though.
Yes, they are big for the current project but
I might work on bigger projects later.

You're definitely right about the S&H costs.
The links were primarily used to make sure that
we're all on the same page.

 

Just thought, dont most modern motherboards come with an IIC port? Or
maybe it is a SPI port. Not sure, but I think it is used to connect to
smart cards and the like.

 

Any such bus would be" internal", not available for outside use.
AFAIK, smarcard reader inclused with mobos would be USB or RS232
serial.