unable to power on after shuttting down with UART cable attached

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Edited by AR9285 at Dec 23, 2015 03:58

Hardware: banana pi
Symptom: unable to power on after shutdown with UART cable attached, need to remove UART attachment to power on again

Steps to reproduce:

1. shutdown using 'shutdown -Ph now' with UART cable attached to CP2102 debug board, which is plugged into a computer
2. remove micro-usb DC-IN
3. reattach micro-usb DC-IN to power up
4. Board fails to power up, power led turns on red, but 'activity' led remains dimmed, UART has no output

Expected Behaviour: No need to remove UART cable to re-power on the device

Note: VCC is not attached, only GND, TXD and RXD

It seems the power from UART cable keeps the device in a slightly 'working' state, preventing the board from properly powering up.
Anyone expierenced this problem?



I have more or less the same problem with one of my BananaPI : it won't shutdown when the LCD is connected.



Just as an experiment,could you insert,say,10k resistors in the tx and rx lines to provide some isolation.

or try with a different usb-uart board,with a different controller,if you have one lying around.

Thanks for the advises, I'll check.

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