The nRF Toolbox DFU is a modification of the nRF Toolbox application, with only the DFU profile left.
To open the DFU settings click the Settings button in the top toolbar when on DFU profile.
Packet receipt notification procedure - This switch allows you to turn on and off the packet receipt notification procedure. During the DFU operation the phone sends 20-bytes size packets to the DFU target. It may be configured that once every N packets the phone stops sending and awaits for the Packet Receipt Notification from the device. This feature is required by Android to sync sending data with the remote device, as the callback onCharacteristicWrite(...) that follows calling method gatt.writeCharacteristic(...) is invoked when the packet is written to the outgoing queue, not when physically transmitted. With this procedure disabled it may happen that the outgoing buffer will be overloaded and the communication stops. The same error may happen when the N number is too big, about 300-400. The receipt notification ensures that the outgoing queue is empty and the DFU target received all packets successfully.
Number of packets - This field allows you to set the N number describe above. By default it is set to 10. Depending on the phone model, devices may send and receive different number of packets in each connection interval. Nexus 4, for instance, may send just 1 packet (and receive 3 notifications) while Nexus 5 or 6 send and receive up to 4 packets. By customizing this value you may check which value allows for the fastest transmission on your phone/tablet.
MBR size - This value is used only to convert HEX files into BIN files. If your packet is already in the BIN format, this value is ignored. The data from addresses lower then this value are being skipped while converting HEX to BIN. This is to prevent from sending the MBR (Master Boot Record) part from the HEX file that contains the Soft Device. The compiled Soft Device contains data that starts at address 0x0000 and contains the MBR. It is followed by the jump to address 0x1000 (default MBR size) where the Soft Device firmware starts. Only the Soft Device part must be sent over DFU.
Keep bond information - When upgrading the application on a bonded device the DFU bootloader may be configured to preserve some pages of the application's memory intact, so that the new application may read them. The new application must know the old data format in order to read them correctly. Our HRS DFU sample stores the Long Term Key (LTK) and the Service Attributes in two first pages. However, the DFU Bootloader, by default, clears the whole application's memory when the new application upload completes, and the bond information is lost. In order to configure the number of pages to be preserved set the DFU_APP_DATA_RESERVED value in the dfu_types.h file in the DFU bootloader code (line ~56). To preserve two pages the value should be set to 0x0800. When your DFU bootloader has been modified to keep the bond information after updating the application set the switch to ON. Otherwise the bond information will be removed from the phone.
External MCU DFU - The DFU service from the library, when connected to a DFU target, will check whether it is in application or in DFU bootloader mode. For DFU implementations from SDK 7.0 or newer this is done by reading the value of DFU Version characteristic. If the returned value is equal to 0x0100 (major = 0, minor = 1) it means that we are in the application mode and jump to the bootloader mode is required.
However, for DFU implementations from older SDKs, where there was no DFU Version characteristic, the service must guess. If this option is set to false (default) it will count number of device's services. If the count is equal to 3 (Generic Access, Generic Attribute, DFU Service) it will assume that it's in DFU mode. If greater than 3 - in app mode.
This guessing may not be always correct. One situation may be when the nRF chip is used to flash update on an external MCU using DFU. The DFU procedure may be implemented in the application, which may (and usually does) have more services. In such case set the value of this property to true.
In order to compile the project the DFU Library is required. This project may be found here: https://github.com/NordicSemiconductor/Android-DFU-Library. Since version 1.16.1 it is imported automatically from jcenter repository and no special configuration is needed. If you want to make some modifications in the DFU Library, please clone the DFU Library to the same root as nRF Toolbox is cloned and name the library's folder DFULibrary. Add the dfu module in Project Structure and edit app/build.gradle file and settings.gradle files as describe in them.
- Android 4.3 or newer is required.
- Tested on Nexus 4, Nexus 7, Samsung S3 and S4 with Android 4.3 and on Nexus 4, Nexus 5, Nexus 7, Nexus 9 with Android 4.4.4 and 5.
- Compatible with nRF51 devices that have S110 v5.2.1+ and the bootloader from nRF51 SDK v4.4.1+ and nRF52 with S132 SoftDevice.
- Development kits can be ordered from http://www.nordicsemi.com/eng/Buy-Online.
- The nRF51 or nRF52 SDKs and SoftDevices are available online at http://developer.nordicsemi.com.
- Nexus 4 and Nexus 7 with Android 4.3 do not allow to unbind devices.
- Reconnection to bondable devices may not work on several tested phones.
- Nexus 4, 5 and 7 with Android 4.4 fails if reconnecting when Gatt Server is running.
- Reset of Bluetooth adapter may be required if other errors appear.
- Setting Package Receipt Notification to O (disabling) or less than ~400 may overflow the outgoing queue and hangs the Bluetooth adapter. Use values around 12 for better performance. If you get an error on a recent phone (e.g. Nexus 6P) just after the DFU is started change the value to 4. DFU may have problems with saving packets to the flash memory if the connection uses 6 packets on each connection interval.