How to deal with VCC on Tiny Shields

[mkroll]

Hello everyone,
I was studying the schematics of the TinyDuino and the programming adapter last weekend.
I want to create a temeprature shield as initial project to deal with TinyDuino.

What if a part on the Shield does not support 5V? If the USB Programming Shield is connected to TinyDuino, the uC and all other shields
are powered with +5v from USB. When the uC Board is powered by a battery VCC is VBAT ~3V.

Now what? Do I need to add DC/DC converters and level shifters on 2x2cm in order not to blow my shield, or should I design it to work with VBAT on VCC only and tell the users not to connect the shield while programming or debugging?

I'm just interested how TinyCircuits will design future shields which are providing more functionality compared to the breakout boards and the 16 LED Shield. How do you do that?

Thanks for your advice,
Michael.

[TinyCircuits]

Hi Michael,

It's a great question, and the 3 vs 5V issue has long been a problem with Arduino shields in general.  We have taken the approach that all of our TinyShields will support 3 - 5V operation.  So to do this, we include a local power supply and level translators if necessary on the shields.  We're using the TI TXS0102 and TXB0104 translators, and in bulk these are cheap enough to not have much of an impact on the final shield cost.   

So the nice thing from a TinyDuino user, is that any of the shields we offer will work with your system powered from 3 - 5V, and you don't need to worry about the voltage of a particular shield, or the possibility of blowing up an SD card due to powering it a 5V, etc. 

Thanks,

Ken