Reprogramming the Interface MCU on nRF52 Dev Kit

[Mike O.]

I am trying to become familiar with nRF52 code by developing on the nRF52 Dev Kit.  However, I seem to have somehow "broken" the interface MCU code.  It stopped allowing me to transfer code to the nRF52832 chip (drag-n-drop). So I decided to reprogram the interface MCU (ATSAM3U2C) with the code I found here: nRF52 DK - Downloads - nordicsemi.com.  However, after flashing this with my JLink tool, it appears that I also need a bootloader for the iMCU as well and I haven't been able to find any binaries for this.  Am I correct that the mcu needs two binaries (j-link-ob-sam3u128-v2-nordicsemi-170724.bin & a bootloader)?  If so, where can I find the missing bootloader file?  If not, what else must I do?  Note that the "j-link-ob-sam3u128-v2-nordicsemi-170724.bin" flashes and verifies correctly.

[Amanda Hsieh]

Hi, 

Please try to press the IF BOOT/RESET button while power cycling the kit. It should then show up as a Removable Storage Device named "BOOTLOADER". Then you can drag and drop the J-LINK interface MCU firmware found here (v170724) onto the storage device to reprogram the JLINK firmware.

Regards,
Amanda

[Mike O.]

I am no longer able to get this to happen.  When I first tried this, Windows told me that the file was too large and would not fit in the available space.  After I loaded the file via the standalone JLink programmer, I no longer get the LED to flash when I power on with the reset button pressed.

[Amanda Hsieh]

Hi, 

Try this post.

-Amanda 

[Mike O.]

Progress!  After loading the .hex from your link, the functionality has returned such that the LED flashes and the board comes up as a USB drive when I power up with reset held.  However, now I am back to the original scenario where when I drag the "j-link-ob-sam3u128-v2-nordicsemi-170724.bin" file, Windows says that there is not enough room in the target to copy the file. Maybe I could load this file directly with the standalone JLink if I had the correct address?  The default address will overwrite the new code.

[Amanda Hsieh]

Hi, 

Do all other functions work? Do you see the derive come up as "BOOTLOADER" at this end? This is an important checkpoint. It must come up as "BOOTLOADER". if not, you programmed the actual nRF instead. 

For the drag-and-drop, you can try to run "MSDDisable" via "J-Link Commander" on the kit. 

Since the image is provided by my colleague instead of an official source, there are no guarantees. 

-Amanda