Changing the bootloader of nRF51822 beacon in order to minimise power consumption

[Johnson]

I measured the current drawn by the nRF51822 beacon with its default beacon code. The current was about 1 mA which was same as in another thread

The suggested solution was to change bootloader.c and then uploaded the bootloader to the beacon.

I would like to know the steps to modify and upload the bootloader to the beacon. So far I did the following steps. (A confirmation would be great if this is correct.)

• Open the project file dfu_dual_bank_ble_s110_pca20006.uvprojx in nRF51822 Beacon v1.1.0\source code\nrf51_beacon\ble_app_beacon_dfu\bootloader\pca20006\dual_bank_ble_s110\arm
• Locate bootloader.c and add NRF_POWER->TASKS_LOWPWR = 1; on line 314.
• Build project

When I opened the _build subfolder, I could not find any hex file. So what file should I upload to the beacon?

I assume that I could use the DFU app in the nRF Toolbox Android app in the same way as uploading an application hex file.

[Stefan Birnir Sverrisson]

Hi Johnson

You should use the hex file to upload to the beacon device. The file nrf51822_beacon_bootloader.hex should be created when you build the project located in \nrf51_beacon\ble_app_beacon_dfu\bootloader\pca20006\dual_bank_ble_s110\arm. If not, make sure you have the "Create HEX file" checked in Keil -> Options for target -> Output tab

There are two ways of uploading the modified bootloader to the Beacon kit:

• via the bootloader that resides already on the Beacon kit. Use nRFToolbox -> DFU for Android to upload it. Also possible with the nRF Beacon app, DFU tab. The bootloader will however need an init file to be uploaded with the updated bootloader, see this thread for instructions on how to do that, comment from 2.1.2015. This thread may also provide more basic infomation about the beacon kit if needed.

• via a connected programmer. To program the beacon kit, follow the instructions given on this thread. You need a programmer and an adapter cable to connect the programmer and the Beacon kit. It is also possible to solder wires directly from the programmer to the Beacon kit instead of using an adapter cable.