how to C program to send data by GATT service characteristic value

[jacky]

Dear Sir/Madam,

I have a sensor prototype board using nRF51822 for Bluetooth communication and I am now working on its firmware. I have installed MDK version 5.16 and using Seggar JLink.  I have downloaded SoftDevice S110 and installed it on the system. 

The task of firmware is very simple: send the sensor data every 10ms through the updates of GATT characteristic value. 

I am a newbie to Nordic SoC and Bluetooth but I guess my firmware should be very simple as following:

main()

{

UUID_Service   uuid_svc;

UUID_Charactristic   uuid_char;

long  sensor_data;

//step1: initialize bluetooth

//step2: advertise itself

//step3:  accepts connection

    while(true){

           //step 4:  samples the sensor and updates sensor_data to the service/characteristic of the defined UUIDs

    }

} 

I am not sure whether my above description is correct or not. If I am wrong please correct me.

My problem is that I don't know what functions should be called at each step. Could you give me some advice on it? 

Any suggestion will be welcomed. I do appreciate your help!  

Jun

[Martin Lesund]

Hello Jun,

If you are a beginner I would advise you to check out the links on this thread for guidance.

 

 I assume that you will be using SDK v12.3? If not I would recommend you to use that SDK version since it's the latest for the nRF51 series. and you should also use Softdevice s130. (compatibility matrix)

 

Your application seems simple enough and should be possible for you to achieve by checking out this Tutorial made by Bjorn. It shows you in step 5 how you can read out the Temperature data from a sensor via TWI and you could use the "ble_app_uart" example as reference on how to send the sensor data to a central (phone etc..)

 

To acquire more knowledge on how BLE works, you should check out these tutorials:

• Advertising
• Services
• Characteristics