Arduino encryption nRF51822

[Henrik M.]

Hi there!

I use RedBearLabs Nano (nRF51822) for at setup where I've developed BLE code in Arduino to communicate with apps on both iOS and Android.

Now I need to ensure the communication with encryption.

I've read these to threads for encrypting stuff with nRF51822:

devzone.nordicsemi.com/.../ devzone.nordicsemi.com/.../

I'm not sure how to use your C-based SDK from the Arduino environment - can you please enlighten me?

If this is not possible or advisable, can you please tell me which environment you'll recommend for OSX? I've looked at both mbed, CrossStudio for ARM and tried to use the stand alone GCC compiler (so far no luck - I seem to be missing the make files from the SDK 9 download). But no options is as easy to use as Arduino.

Or perhaps Bluetooth Developer Studio Beta is the way forward (and where do I get my hands on that)?

Looking forward to hearing your reply, hoping that you can tell me that using your SDK from Arduino is easy! :)

Best regards, Henrik, Denmark

Files in folder: /sdk9/examples/peripheral/blinky/pca10028/blank/armgcc:

hrs.hex

[Hung Bui]

As you can see in your screenshot, the makefile is there. Yes the PCA10028 is a specific board, but it has the same nF51822 chip as on the Redbearlab module. So you need to modify the GPIO pin to match with your board. In addition, the chip on the RedBearLab could be a different variant, which has only 16kB RAM when the one on the PCA10028 has 32kB RAM. You need to modify IRAM1 to match with the smaller size of RAM.

[Henrik M.]

Hi @hungbui - my blinky_gcc_nrf51.ld file looks like this now:

/* START */ SEARCH_DIR(.) GROUP(-lgcc -lc -lnosys)

MEMORY { FLASH (rx) : ORIGIN = 0x0, LENGTH = 0x40000 RAM (rwx) : ORIGIN = 0x20000000, LENGTH = 0x4000 }

INCLUDE "gcc_nrf51_common.ld" /* END */

1: I've changed the RAM size to 16KB, but I'm not sure if the Origin(s) are correctly set?

2: Futhermore I'm not sure where to set the GPIO pin?

3: Thirdly, the folder content from SDK 9 seem much different from the guide found here: redbearlab.com/nrf51822-sdk, perhaps the guide isn't at all usable with nRF SDK 9.x?

I managed to build the HRS and merge it with s110_softdevice.hex using srec_cat tool. The resulting hrs.hex file results in a fail.txt containing "SWD ERROR". Nothing much to follow :-( The compiled hrs.hex is attached to my initial question.

[Bill Siever]

The link you've provided to RedBearLabs indicates that their module only works with SDK 6.1 (and earlier). This probably means that they're using the 2nd revision of Nordic's chip. Newer Nordic SDKs require the 3rd revision. (See infocenter.nordicsemi.com/.../nRF51_Series_Compatibility_Matrix_v2.3.pdf for more).

It looks like RedBear's Arduino API is really just the mbed API. (See: github.com/.../nRF51822-Arduino which will download the module at redbearlab.github.io/.../nRF51822_board.zip). You may be able to combine the mbed examples for security (like the BLE_SecureHeartRate at developer.mbed.org/.../) with the typical Arduino function name conventions, like setup() (for startup command) and loop(), for the main loop.

[Henrik M.]

Hmm.. Perhaps I should stop using the RBL Nano, and use the nRF52 instead - but as far as I can see, only the preview DK is available at the moment?

I need to be able to support both encryption and S130 (peripheral AND central at the same time). What do you think my would be my best option?

[Hung Bui]

Hi luposlip,

S130 only support chip revision 3. So if the RBL module doesn't have chip revision 3, you should think of another option. I would suggest you to try the nRF51 DK.

You don't need the nRF52 unless you have an application that require more powerful MCU processing power that the nRF51 can't handle, or some peripheral that the nRF51 doesn't have such as NFC.