Unable to program nrf dongle successful through nrf connect

[Jwang]

I have two nrf 52840 Dongles, and I cannot program either of them:

For the first piece, I have programmed it using conectivity_1.0.0_S132.hex a year ago.  and it works well. I would like to use it as a ble sniffer some time later, but the chip is not recognisable by nrf connect any more after reprogramming. I noticed that there is a newer version of nrf programmer now, so I upgraded it to v3.0.8 and tried again. This time, the chip can be recognised, but no option of erase/write chip is available. So I cannot program it back to S132.

For the second device, it is the same model as the first one. I bought after the first one is unable to be reprogrammed. With an earlier version of nrf programmer, the fw doesnot take effects after loading the new image, (the image remains the same as before) so reprogramming never successes.  After upgraded to this newer version nrfprogrammer v3.0.8, I am able to program the dongle (only write option is available, erase is not), however, once I reprogrammed it once again, there is still no option of erase. I write the image once again, and the dongle could not be recognised by the programmer any more...

I tried to press the reset button and then insert the chip into my computer (no usb hub used in any of the steps before). but it doesn't help.

I wonder how may I put the dongle into the bootloader mode, makes it recognised by nrf programmer, and able to click on erase option?

Thank you! 

[Einar Thorsrud]

Hi,

The dongle does not have an onboard debugger, but instead it ships with a USB bootloader. So programming the dongle happens via USB DFU. However, except for a few application that has special support for it, the dongle needs to be explicitly put in DFU mode in order to be able to program it. This is done by pressing the reset button on the dongle, which is a sideways button marked "RESET", which is right to the left of the "SW1" button. When you pres this, the LED with be pulsating red, indicating it is in DFU mode. Then you can add a file and write it. (It is not possible to select erase though, as that only works via a debugger.)

I tried to press the reset button and then insert the chip into my computer (no usb hub used in any of the steps before). but it doesn't help.

You must press the reset button while the dongle is plugged in the computer.