Nothing happening without USB

[Roy]

Hi developers,

I am having a strange problem: My nrf51822 will only start-up when USB-powered.

From no power state (battery removed and usb-disconnected): ---When inserting battery: Nothing happens: no advertising or LED-blinking

---When inserting USB: The device starts advertising and a LED starts blinking

From USB-connected state(battery inserted and usb-connected): ---When removing USB: Device stays connected only on battery power, advertising is enabled and LED is blinking

---When removing battery: Device stays connected only on USB-power, advertising is enabled and LED is blinking

My question: Is it a hardware on software problem? did I accidently enable some debugging function?

[FormerMember]

Hello,

The issue is hardware related, but it should work fine to run the evaluation kit on battery. I assume you have an evaluation kit? Please try the following:

• Measure that the voltage of the battery is actually 3 V.
• Connect the battery or another external source to pin 3 and 4 on P1 and check if that works.
• Measure the current when running on battery: This can be done by cutting SB 8, and then measure the current by connecting the amperemeter to pin 1 and 2 on P1.

I also recommend you to take a look at the schematic for the evaluation kit so that you can see why the suggestions above should work.

Regards, Kristin

[Roy]

Dear Kristin,

Your assumption was right: i've got an Evaluation kit. The voltage of the battery is 3.2V, so that's enough. I've cut SB8 and inserted a 10 OHM resistor, I measure a Voltage of: 0.0056V so I=U/R = 0.0005 A.

When I remove the Segger jumpers I measure a Voltage of 0.025V => 2.5mA and a LED turns on :D. I think that fixed it. I'll run The master control panel and see if it is advertising. On my Bluetooth 4.0 android device I still see nothing popping up.

------answer----- With the Segger jumpers removed the board springs to life