Powering through JTAG

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doddz
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Powering through JTAG

Post by doddz » Tue Feb 25, 2014 11:04 am

Anybody know if it's safe to power the Crazyflie through the JTAG?

This edu J-link I'm using has a setting to provide power and just thought if I use that I can save having another cable plugged in the CF.



DerShu
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Re: Powering through JTAG

Post by DerShu » Tue Feb 25, 2014 4:36 pm

doddz wrote:Anybody know if it's safe to power the Crazyflie through the JTAG?
The normal function of the power pin on an ARM JTAG pinout is to sense the power supply of the device under test so that the the JTAG interface buffers run at the DUT power voltage. It could possibly do what you want on some target boards, but not on the Crazyflie. The JTAG power sense pin connects to the Crazyflie VCC OUTPUT, so applying power at that point could cause damage, and it also would not power up the whole circuit board either.

doddz
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Re: Powering through JTAG

Post by doddz » Tue Feb 25, 2014 8:01 pm

Thanks for the explanation DerShu! I'll keep that turned off

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