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Netduino does not work when powered by Mac Mini USB


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#1 nimble

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Posted 08 August 2012 - 09:34 PM

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?? Thanks

#2 Chris Walker

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Posted 08 August 2012 - 10:04 PM

Hi nimble, There are two possibilities here... 1. Your Mac Mini may not be delivering enough power to run the Netduino when you first plug it in. What happens if you plug in the DC power and then remove that extra power after it boots? Technically USB ports don't need to deliver more than 100mA to a board until the board has enumerated...which creates troubles for development boards sometimes. There may be a USB setting you can set on your Mac Mini if this is the case. 2. Your Mac Mini may not be delivering the 500mA of current that USB specs. If you plug in external power and the Netduino can't run via USB power after the external power is removed...this is probably the case. Do you have additional components plugged into your Netduino? Or is it just the mainboard? Chris

#3 ErikN

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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??

Thanks


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.

#4 nimble

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Posted 10 August 2012 - 02:01 AM

Hi guys, Thanks for the responses. My netduino is constantly powering a quad-and-gate and an IR receiver. I could probably throw a transistor in there to power off all those devices until after the unit has fully booted. I will have to give all your suggestions a try tonight, and report back. - Adam

#5 nimble

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Posted 11 August 2012 - 06:00 AM

Reporting back... Yes hitting the reset did work - odd it didnt work at first (it was the FIRST thing I tried before posting my problem online) - but then after unplugging everything from my Mac, and trying again I had the same problem, but now the reset button resets the unit and it is then fine... 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. Thanks guys

#6 Chris Walker

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Posted 11 August 2012 - 09:30 AM

Hi nimble,

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.

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.

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.

Chris




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