Netduino does not work when powered by Mac Mini USB
Posted 08 August 2012 - 09:34 PM
Posted 08 August 2012 - 10:04 PM
Posted 09 August 2012 - 12:34 AM
I have been developing my Netduino application on a Windows desktop machine - but my deployment scenario is going to involve powering the board from a Mac Mini USB port (currently a Mac Mini 2012 model).
What I have discovered, is that if I plug my netduino into a Mac Mini USB port, the on-board LED lights up, but stays on - and my program never loads.
If, I plug it into my PC, or a wall-wart USB power supply, the on-board LED lights up for a few seconds, then goes out as my program loads into memory, and everything works.
Why does my Netduino not run correctly when powered by Mac Mini??
I noticed a similar issue. All I had to do was tap the reset button and it'd come up just fine. I noticed as soon as my VM running on the Mac Mini was set up to automatically attach the Netduino to the Windows instance, this stopped happening. Before that it was reliable to just reset the board and it'd come straight up.
Posted 10 August 2012 - 02:01 AM
Posted 11 August 2012 - 06:00 AM
Posted 11 August 2012 - 09:30 AM
The Mac issue exists for boards/circuits which draw more than 100mA of power during enumeration. With Netduino Go we added extra circuitry to allow us to address this by shutting off power to all modules during boot. We also added circuitry to the Shield Base which lets us power off shields (via the 3V3/5V headers) at boot. If there's enough demand, we could add those same circuits to a Rev C of the Netduino Plus board.
What does this mean Chris? That the Mac doesn't support the initial current draw of the unit? Its a bit of a hiccup for creating the final product - however it might not be a problem this time, because I am considering implementing the final product using a Cerb40... so probably a whole different set of problems.
Regarding the other NETMF board you mentioned... You'll want to measure the power consumption, as the MCU alone may consume more than 100mA during boot. Your timeline may be good for using it, as I understand that they're revising the board (correcting capacitor values) to enable its advertised features. For commercial applications, you may want to pick a board without the potential royalty requirements.
Netduino Mini might be a good pick depending on your application, and Device Solutions makes some nice NETMF modules too. Lots of options to pick from for commercial use, if you want to go small.
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