Amicus18/Arduino/Whatever voltages

[dhouston]

In designing the shields I want to be sure the correct voltage is supplied to the modules. The ConnectOne modules use 3V3 and are not 5V tolerant. The Tibbo is 3.3V but its input pins are 5V tolerant. I'm not sure about the GA1000 but it only connects to the EM500 and to the save 3V3 source. The flash chip is 3V3 and also only connects to the EM500. I need to make sure that they not only have a 3V3 supply but that the supply is also capable of the rather high currents drawn by the WiFi modules when transmitting (250-350mA).

The problem is that with the proliferation of compatibles, there seems to be a plethora of power schemes. For example, the Arduino Duemilanove (and compatibles) automatically switches between USB power and an external source (if one is plugged in) but I'm not at all certain what will be on the 5V, 3V3 & Vin pins under various scenarios. The 3V3 supply on this model is taken from USB which can only supply 50mA. I have no idea what Vin equals if the external supply is 3V3.

Any suggestions from all of the shield experts here?