TI CC2541 (BLE): Send data (to an Android phone)

Question

I am experimenting with Bluetooth Low-Energy (BLE) for the purpose of connecting a hardware device to an Android application. My goal is to send a recognizable piece of data to an Android phone.

I am using the keyfob from Texas Instrument's CC2541 Mini-development kit, and am programming it using the IAR Workbench (which I am learning on the fly). My issue is that I cannot figure out what code should be used to send data from the keyfob to the phone.

I understand that this is somewhat vague, but because of the non-disclosure policies of my company I cannot share the code that I am working with. Does anyone have any references to code for the IAR Workbench that will allow the CC2541 to send a piece of data? Right now, I prefer to use GATT if that helps.

Thanks, and please ask me more questions if I need to clarify anything.

Answer 1

Assuming you're working from a pre-existing service profile, there is a function for every service called ServiceName_SetParameter(). Calling that function will change the characteristic value. When the characteristic is read by the phone, it will receive this value. If the characteristic supports notifications, and your phone has registered for notifications on that characteristic, the new value will be transmitted whenever SetParameter is called.

Answer 2

You can implement any proprietary protcol to connect to and interact with your beacon device. It can assume other roles than just the beacon task. It can also listen to and respond to connection attempts thus expanding into a lot more than a regular beacon. If you study the cc2541 close you realize it is a pretty advanced IO controller that offers a lot of IO signal possibilities. That way you could use the cc2541 as the heart of an IO control application where you measure and control equipment. Mobile apps can then easily connect to your beacon/IO Controller device and interact with the machinery it is hooked up to. As you see, it´s a remarkably versatile system on chip and a cool circuit to learn to program.