Beaglebone Wireless - does not start up

I have two new beaglebone Wireless board, and if you connect the usb to a powered usb hub, the processor does not start-up. There is a single flashing light on the PWR led but none of the processing LED light up.

If I supply power on pins P9 1 and 5 , there is the power led flashing but the board does not start-up.

The only way I can start the boards , if I restart my PC then connect the usb. Everything starts and it runs as long as there is power.

So there is an issue with the boot up sequence or the clock or something but both boards do not start-up on power up.

These boards are new fresh out the box. In my application they are must start up on power up and are not connected to any PC through the USB hub.

I have seen that another users has the same experience but no solution given. As a electronic engineer with 40 years experience in firmware , coding I think this is a firmware issue on these new boards.

Any help would be appreciated.

I heard that with some hardware the cause of such behaviour is the USB hub back-feeding 5V DC into the host USB port. That could disrupt the normal power-on sequence in a circuit that was not designed to anticipate that. If that’s indeed the case, you could use a hub that conforms to the USB spec, or fit a low voltage drop type diode into the hub’s 5V0 wire if you are comfortable with basic electronics.

I would put a scope on the power input and watch the rise, fall and overshoot on the output from your power supply.

The BeageBone Black has a PMIC chip that has some tight power requirements, input rise time is 50 ms max, the maximum voltage is 5.5V and minimum is 4.5V or the PMIC chip will go into self protect.

If, when you turn it on, the Voltage overshoots temporarily above 5.5 Volts, as my B&K 1550 does, then the Beaglebone will not boot, and you get a single blink, because the PMIC went into self-protect.

I suggest that you get a different 5.0 Volt supply, not a variable bench supply, and re-run your experiments.

— Graham

Thanks for your replies.

I have done some more testing and if I use a raspberry pi power supply Vilros 5v 2.5 amp to USB supply it starts every time.

Now if I add a USB keyboard and hmdi monitor then try to power up, it does not start on the same power supply as above.

I cannot get it started from any usb port , or power hub. From my PC I can only get it started if I restart my pc and then plug in the usb port. If i remove the usb and replug it , it will not start unless I reboot my PC.

I think the wireless probably draws more current on start-up so it requires much more current that the normal beaglebone black.

I have three new Beaglebone Black Wireless devices , straight out the box and this issue is with all of them, so I am sure it is not anything that I have done but an issue with the devices and the PMIC chip specs.

So this is a product defect issue and probably is wide spread.

The Voltage specs are the Voltage specs.

You need a solid power supply, and good quality USB cables with appropriate wire sizes.
If there is a USB-Hub involved, best to power it separately.
A lot of the “no-name” USB cables have less copper, therefore more resistance and more Voltage drop than they should.
Longer cables have more Voltage drop than shorter ones.
Use the shortest USB cable that will get the job done.
If you need a longer USB cable for some reason, buy it from a quality supplier.

How much current does the HDMI Monitor draw? Could be a lot.
Can you power it separately?

— Graham

Hi Graham,

Thank you for your advice, it definitely pointed me in the right direction. So we can get is running if we have of number of caps on the supply.

This is going to be a real issue for this product, if it just does not power up using a powered usb or even the usb on the PC. If the users struggled to get this turned on like I have I think this is a serious issue.

I am used to just supplying power and turning on the device - I really don’t think 2 days of testing just to get the device on is a good start.

Most other users are going to have the same issue.

Anyway I really appreciate you knowledge.

Thank you.

I had similar issues with Raspberry Pi because none of my fixed voltage pretend-5V power supplies or USB ports had the capability to maintain 5.0V DC (which would be acceptable). Under load the voltage sagged to 4.7V and the Pi firmware monitor kicked in to blink the alarm and to throttle the CPU. Still it managed to boot.

The next step was to borrow an adjustable voltage 25A power supply (30mV ripple claimed under ham radio loads). With voltage set to 5.1V the issue went away, so I ordered the vendor’s recommended 5.1V power supply and the problem was solved.

If you do not want to splash on a oscilloscope, consider at least a multimeter to see how close what’s on the wire is to what’s on the label.

Hi Denis,

We managed to fixed the problem once you pointed us in the right direction.

It is just that we never thought it was a power supply problem as all the documentation for Beaglebone basically implies that the USB Power would be okay.

Anyway thank you for all your advice, it was valuable and much appreciated – we are on the right track again.

Thanks
Bryan

Hi

I am having a similar problem with an element14 beaglebone.

Power led blinks but no startup.

No problem with a beaglebone black.

Which power supply would be the best to use?

Thanks
Ken

I used a cheap supply from Amazon, 5v, 2.5 A. The manufacturer is Vilros and it is designed for the RaspberryPi.

I think it is an issue with the start-up current that pulls the voltage down briefly on start-up. I don’t think it is a BeagleBone Black issue but it is on the BBB Wireless as the Wireless probably draws more current on start-up.