power on issues while connecting external supply

[hariharan_srm]

HI i am using nordic nrf52840 dk(pca10056) . i am using ble_app_uart example code for my development. i have connected usb in j2 but when i keep my power switch in usb adv led is not blink while keeping only on vdd with j2 on usb supply the ble is advertsing  why?. i want to know how to give external power supply to the board what are the procedures needed to be done whether any jumper switching or any soldering should be done . and how much volatge should be given to external power supply to the board. and then when i connect the nrf52840 tx pin with my lpc controller my lpc controller rx io getting low whether it nordic has been pulling low the io(rxpin) of my controller  

[Menon]

Hello,

i have connected usb in j2 but when i keep my power switch in usb adv led is not blink while keeping only on vdd with j2 on usb supply the ble is advertsing  why?.

It won't work this way. If you're keeping J2 connected (the debugger) and selecting "USB" on the nRF power source switch, the board is NOT getting proper power to the nRF52840 SoC. I think that's why the advertising doesn't start. You can use the P21 EXT supply header to power the board externally. I recommend checking the DK hardware specification.

Kind Regards,

Abhijith

[hariharan_srm]

i have connected usb type(b) to j3 and kept the switch to usb but no advertsing happens and i have also connected external supply 3v to p21 the board is not on . only while connecting usb with j2 and keeping the switch on the vdd mode board works . whetherany jumper has be connected or any solderings to be made between any things. i have also kept the nrf only to default siwtch in both ways but no board powersup. i wan to step by step procedure to connect the external supply to p21 i have connected the volateg and gnd to p21 but no boot happening