Connect One Ethernet shield

[dhouston]

Arduino is not AMICUS18 and XINO is not Arduino - simple as that. I looked at the datasheet for the ATMega 328 which I believe is what is used on the Arduino. It operates on anything from 1.8 to 5.5V so THAT won't be a problem. If the Arduino contains a voltage regulator and the option to actually RUN it at 3.3V instead of 5V is another question.

Henrik, I agree with your points.

I envisioned this more as a prototyping/testing platform in the spirit of the Arduino ethos: Open Source Electronics Prototyping Platform (printed on the Arduino Uno box) and wanted to keep it as universal as possible. But, the different voltage requirements add complications I had not forseen. Had I designed the Arduino or the Amicus18 I would have made both powered externally from either 5V or 3V3 Switch Mode Power Supplies which can supply high amperage. But, I'm having to adapt to what's already on the ground. I've never had any plans to produce these myself.

I will stay with 3V3 and make it necessary for the end user to verify the supply voltage and solder in a jumper as needed. I will look at adding the footprints for a regulator and necessary caps, etc. but these will be SMT (there's limited free space) so neophytes will be better off with a 3V3 main board (Amicus18 or compatibles). If Xino or others want to offer the boards, it will be up to them whether to stock them with/without regulator, et al or supply one version with regulator and jumpers. The ConnectOne (and Tibbo) modules plug-in so these still are good for testing before deciding on a final (perhaps unrelated to this form factor) design.

For my own testing and protyping, I think I can adapt an Arduino Duemilanove to use only external power and then use 5V or 3V3 as needed. I also need to replace the 20MHz crystal with a socket so I can choose 14.7456MHz or 7.37MHz depending on MCU (ZX-328n, ZX-328l) The Mega328P can use lower voltages but needs a slower clock speed to reduce the current draw.

Finally, ConnectOne has agreed to have an engineer review the plans. This means I do not need to find testers for each incarnation.