Arduino Mega with integrated W5100 ethernet...

I have a project that is currently in pre-production testing that has a few custom boards (which are being turned in a single I/O PCB) and a WIZnet WIZ811MJ plugged into a MEGA using the shield kit from adafruit.

To enable the box to be as small as possible (and because the piggy-back approach isn't really suitable for production purposes) I'm considering taking the MEGA reference design & adding a W5100 chip directly onto the board.

Although I don't need to keep the dimensions even remotely similar to the Arduino ones for my own purposes, I thought that other people might be interested in a board with this facility.

Thoughts:

1] Remove the USB port & controller chip as a means to claim a fair amount of the space needed. 2] Change the voltage regulation circuit so that the whole thing can run properly off a 9V power supply (7, 7.5 and 8V power supplies are difficult to get hold of.

Feedback?

Here's a couple thoughts. Of course these are just my own opinions and therefore don't count for much....

1] Remove the USB port & controller chip as a means to claim a fair amount of the space needed.

Arduino boards tend to go through a whole lot of programming development cycles and ease of use is important. I wouldn't want to have to develop a new app and have to upload hex files using the ICSP header and PonyProg for each test cycle. Could you make it programable through the Ethernet connection?

2] Change the voltage regulation circuit so that the whole thing can run properly off a 9V power supply (7, 7.5 and 8V power supplies are difficult to get hold of.

Huh? As far as I know the MEGA design (as with most other Arduinos) will run happily off of anything between 6v and 20v (I've been using 12v). I have noticed that they didn't pick easy chips to buy in small quantities for the voltage regulators though. It would be nice to have something easily sourced.

You may have noticed in the Madhuino design that I'm working on that the upper 16 I/O channels were sacrificed to make room. You could do something similar ;) and still retain "classic" shield compatibility. There don't seem to be many other choices other than what you proposed, and what I am trying, to fit additional components on the MEGA reference board. Although did you see the other topic with the micro-MEGA that still has all the pins broken out? I can't imagine how that was done in 2 layers!

Arduino boards will run quite nicely even when supplied with 12v (though the regulator does get a bit warm) but, due to the way it works, it can't supply enough current to the W5100 chip.

Have a look at http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1241924251/7 for more info.

With the USB connection, I should have been clearer. I am planning on putting on a header for one of these instead...

http://www.adafruit.com/index.php?main_page=product_info&cPath=33&products_id=70

The benefit is that the lead can be re-used over as many boards as you build and the cost of the USB chip, etc. is removed from the board (athough the ethernet components need to be factored in).

Personally, I really love the Mini Megadunio. The project I am designing this for has another board that would be more ideally suited to pins rather than sockets.

On the subject of losing I/O ports, I can't do that for my project either; I'm using 42 digital I/Os and may need four more later...

Thanks for the feedback :)