Softdevice example doesn't start when powered by other source than MCU interface.

[Francois5Co]

Hi,

Recently I receive the "nRF52840-Preview-DK" and I download the "nRF5 SDK v14.0.0". I try some example with Keil and all of them works well when I use the MCU interface. But when I try to powered the board with other source than the MCU interface only examples that do not include softdevice works. Examples with softdevice seems to doesn't start. I have the same problem if I copy directly the hex file on the JLink storage manager.

[endnode]

What do you mean by "power the board with other source then MCU"? You always power the board just with Volts not MCUs;) You can use 5V USB on the Dev Kit or attach different 5V source through the PIN on the header, or you can power it directly through 3V3 or you can use battery holder on the Dev Kit...

If you have problems with flashing the target then use nRFgo Studio, nrfjprog (from NRFTOOLS package) or similar tool which has some logs in case of error. That will tell us more.

[Francois5Co]

I mean power the board with the 5V on the usb connector used for the MCU. If I powered the board with a 5V in the other usb connector (J3, directly connected to the nRF chip) only example without softdevice run on the device.

[endnode]

OK. So at least nRF52840 is alive, that is good. Now what exactly is the difference between working and not working examples? How you flash it to the board (when you have SEGGER J-Link disconnected because you plug only USB cable directly to nRF52)? Which example HEX files work and how these with Soft Device misbehave? At least some debug trace from UART or RTT?

[Francois5Co]

For example, I connect the demo board with a USB cable to the MCU Interface (J2), I copy this hex file "nRF5_SDK_14.0.0_3bcc1f7/examples/peripheral/blinky/hex/blinky_pca10056.hex" to the removable file named JLINK and now I see the 4 led blinking. Now I disconect, the USB cable, I don't move the nRF power source selector (SW9) VDD is still selected and I connect the usb cable to the nRF USB connector to power the board and I can see the led blinking.

Now I reconnect the demo board with a USB cable to the MCU Interface (J2) , I copy this hex file "nRF5_SDK_14.0.0_3bcc1f7/examples/ble_peripheral/ble_app_uart/hex/ble_app_uart_pca10056_s140.hex" to the removable file named JLINK and now I see the led 1 blinking, and I can see "Nordic_UART" device if I scan BLE devices. Now I disconect, the USB cable, I don't move the nRF power source selector (SW9) VDD is still selected and I connect the usb cable to the nRF USB connector to power the board and the four leds are switch on with few luminosity and if I scan BLE device I didn't found the Nordic_UART device.

[endnode]

Nice. If you want to power the target from USB then you need to move SW9 to USB, at least this is how I read nRF52840 PDK user manual... definitely worth trying to use other means like external VDD to VIN PIN of P20 or battery and see if then BLE works on the target. If so then you just have wrong setting of SW9 and 10 while powering through USB (or other problem like bad cable).