Shield pin usage list

Deary me you're right, J1 = J3 and J3 = J1.

I latched onto the designations assuming that they would be a defined standard not left up to the whim of every PCB designer. I know you normally designate components in a logical progression across/down a PCB but with a standard all important components should be called the same thing by everyone and Arduino is arguably a standard.

You live and learn eh? Sorry for the confusion.


Rob

Alright! Then it's arduino digital pin 4 then. Thank to both of you! I will attach a button to arduino digital pin 2 since it's unlikely used.

Would it be a problem that the 'Shield Image' form accepts a link to an image as well? Saves me (us) a download and upload of the image.

That's possible, it just means that I would have to download and upload it instead. None of the fields on that form are required though so for shields where people don't include an image I just look for one myself. In fact in some cases the images uploaded by submitters are very poor quality so I go and find a better one myself anyway.

Thanks for the suggestion!

Jon

The official Ethernet shield came up as an early problem for me when adding to @GrayNomad's list, because it's been available in several versions. The latest one is (I think) version 5, and the record in the DB is mostly a reference to v4 (including the photo) but the pinouts are for v5.

I'm intending to duplicate the record and have separate entries for v4 and v5.

Jon
Super-cheap prototyping shields: ProtoShield Basic for Arduino | Freetronics

The official Ethernet shield came up as an early problem for me when adding to @GrayNomad's list, because it's been available in several versions. The latest one is (I think) version 5, and the record in the DB is mostly a reference to v4 (including the photo) but the pinouts are for v5.

I'm intending to duplicate the record and have separate entries for v4 and v5.

Maybe have one page for the latest version but then have links off that for previous versions. Saves filling the site up with lots of versions of shields.

Mowcius

Thanks for the great list, now it's far easier to create my Xmas wish list :slight_smile:

An idea came into my mind when reading this discussion. Could shield manufacturers place a mark which pins the shield uses? e.g. a square or a circle around the pinnumbers or just inverse print the number on the shield itself, or don't print the numbers used as these pins are not available? As I have no experience in designing boards I do not know what's possible or easy to do. Are there reasons not to mark the pins? e.g. some pins are optional and others aren't? Different markings?

Just thinking out loud,
Rob

Rob, sounds like an easy thing to do. Maybe some companies would take it on board. I would put a box around them or some kind of other indication like you said.

Mowcius

Hi Mowcius,
Could it be standardized in some way? e.g. in the shield development guidelines? Does such a doc exist? only saw http://arduino.cc/en/Main/ArduinoShields

Rob

Could it be standardized in some way? e.g. in the shield development guidelines?

Possibly but nobody would ever read it. People always do what they like.

It's a good idea though. I will pass it round...

Mowcius

Good idea Rob, that's something I've been telling people for a long time! There's been some discussion of shield design standards in places like this:

One of my personal irks (and one of the reasons for http://shieldlist.org) is not being able to figure out what pins are used on a shield simply by looking at it. I mentioned it in the video review I did mid last year for the WiShield v1, and asynclabs subsequently fixed it in v2. The original video is embedded here:

http://shieldlist.org/asynclabs/wishield-v1

I'm doing a talk about "Arduino Shield Design Considerations" at the Arduino Miniconf in Brisbane, Australia next January, too:

http://lca2011.linux.org.au/wiki/Miniconfs/ArduinoMiniconf

Jon
Arduino-compatible "TwentyTen" with built-in prototyping area: TwentyTen (100% Arduino Compatible) | Freetronics

On a similar note, that's why I came unstuck looking at the Etthernet shield schematic the other day, P1 and P3 where "swapped" between the shield schematics and the Arduino but I assumed that there was a standard and "P1" was the same on all schematics.

Usually you name components in order on a board so they are easy to find but for important, common, and static components like these headers I think they should have standard names. If not P1 etc then "Power", "Analogue" etc. This is often done on the PCB as mentioned, but they they should have standard names on the schematics.

This is a good argument for the Apple model whereby a single entity defines what will be done and there's little room for interpretation. That's not the model we want here I guess but some standardisation should be striven for.


Rob

Hi Jon,
Thanx for these sites, lot of good info. these sites should be mentioned on http://arduino.cc/en/Main/ArduinoShields but I have no rights :frowning:
Furthermore you might put a link "Shield Design Considerations" on the homepage of http://shieldlist.org/ and teach the world :slight_smile:

Rob

One of my personal irks (and one of the reasons for http://shieldlist.org) is not being able to figure out what pins are used on a shield simply by looking at it. I mentioned it in the video review I did mid last year for the WiShield v1, ....

;D I used pet peeve in my write up here last week

If you have ever seen Jon Oxer, author of the book Practical Arduino, discuss a shield, as he does in this video review of AsyncLabs WiShield for Arduino, you would probably easily observe that one of his pet peeves is designs that dont let you know shield pin assignments when using the shield.

Because I couldn't catch the term you used, what was the term at
4:42 was it bug bears?Video 4:42

One of my concerns has been I would like to add more to the list but just can't tell what pins are used on some boards I have found, that aren't in the database, but I just I dont know how to enter them.

My concern was if I entered them with the wrong pins(as in guesses) it might stop someone who would know would then not enter the right info, so I just chose not to enter them.

Would you still like the info entered?

Om nom nom free stuffs :slight_smile:

Do I get something for each shield I submit or just the one? :smiley:

Would it be tricky to add the ICSP header onto your pin usage diagram? Quite a number of shields use it now (especially to become mega compatible).

What about Mega shields, you accepting those too?

Mowcius

Hmm no free stuffs yet...

Mowcius waits patiently.

Hi Mowcius, I emailed asking for your postal address but I don't think I ever got a reply. I've just searched my email again to make sure and I can't find anything.

Could you please email your postal address to jon@oxer.com.au again?

Cheers

Hi Mowcius, I emailed asking for your postal address but I don't think I ever got a reply.

Hmm, didn't receive anything but it might have been due to my end. My email program had a phase of sending out random reply email addresses...

I'll send it. :wink:

The website's coming on great.

Mowcius

You should make sure you have a way to handle optional pin usage.

My new motor shield http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1288647984/0#0 can use any of the 6 PWM outputs, several of the digital outputs for enable and any of the 6 analog inputs - all user selectable via jumpers.

Further different numbers of pins can be used for this shield in different operational modes. The minimum number is 1 and the maximum is 5.

It doesn't seem fair to say the unit uses all of the possible pins and yet it should be indicated somehow those CAN be used.

Just a comment, hard coding particular pins seems dumb to me if you want your shield to be able to work with others.

/me

You should make sure you have a way to handle optional pin usage.

That would be nice, but I haven't figured out a nice way to handle it. It would add a lot of complexity to the user interface (both current and intended) for the site because there are so many possible scenarios.

It's not as simple as adding a third pin option so they can be flagged as "used", "not used", or "optional". Often the options are tied together, so a shield may use one combination of pins in one mode and another combination of pins in another mode. A good example of this is the Spikenzie Labs Button 64 Shield (Arduino Shield List: SpikenzieLabs Button 64 Shield) because it can use either:

D0

OR

D2, D3, and D4

but not both groups at the same time.

So if I just marked D0, D2, D3, and D4 as "optional" it would be technically correct, but just as misleading as marking them as all used. People might think they could use any one of them or even none of them when that's not the case. D2-4 would really need to be bound together into a group, and D0 defined as another group, and those groups be defined as mutually exclusive but with one or the other required. But how would that be represented visually?

Mutually-exclusive-but-required groups is one scenario. Then there are others such as optional pins that are required by some features that may not be used by others such as the SD card slot on the new Ethernet shield that may not be used by many people (Arduino Shield List: Arduino Ethernet Shield v5.0). Or shields that are nothing but breakouts, so they could use all the pins or none of them, depending on what else is attached (Arduino Shield List: Seeed Studio Electronic Brick Chassis v1.1).

Showing optional pin usage sounds good in theory, but when you try to figure out how to actually store / represent that information it suddenly becomes a surprisingly difficult problem!

For now I'm handling it by marking the "default" or basic pin use in the DB, and adding a text note about alternative assignments. At least having all this info in text form in one place is a huge improvement on how things were a month ago.

Jon
Freetronics: www.freetronics.com

As a minimum I'd say we need the SPI header as some shields now use that and some bring it up with through headers too.

Mowcius