DEVPACK-LED-AUDIO + Sensor Tag

Hello Milen,

Most of the cellphone manufacturers impose throughput limitations on BLE, so you will find that the CC2640 can far exceed these limitations. It is therefore important to know your actual throughput & latency requirements before selecting BLE. Providing as much detail as possible will help you receive guidance.

Best wishes

Hi JXS,
Thank you for the fast response!

I have the next clarification from my audio specialist:

- latency: For this project the latency is low priority requirement. As example 500 milliseconds is OK.
- throughput: We understand the parameter as related to the bandwidth. As target the bluetooth media has to provide transmission of voice which will be pre set with preamplifiers and filters in the band from 200Hz to 4KHz.

Thank You again!

Looking forward!

Milen

Hi Milen,

A 4kHz bandlimited signal would need to be sampled at least 8kHz to obey Nyquist rate. This means you must send and process data every 0.125ms in order to stay within your real time requirements.

As JXS mentioned, you will most likely be limited by the phones that you are using.

I would recommend looking up the spec on the phone platform you are using and see if it too can meet the real time requirement of your system.

Hi Sean,

Thank You for the advice.

As I mentioned in the first post the system includes:

1. Microphone, which I will build based on the Sensor Tag + LED Audio.

• Microphone transmits only voice.
• Bandwidth 4kHz
• Small Battery supplied
• Latency of the transmission is not important
• Receiver is at 2 inches distance.
• the microphone with special requirements is under development.
• I will interface it to the existing microphone on the development pack

2. Speaker, which I will build based on the Sensor Tag + LED Audio.

• Speaker receives only from the microphone transmitter.
• Distance 2 inches.
• Speaker delivers only voice.
• Bandwidth 4kHz
• Big Battery supplied
• Latency not important.
• Quality of the sound is very important.
• I will interface it to the existing speaker on the development pack

3. Cell phone compatibility

• This is not cellphone product.
• The protocol of communication has to be compatible with some of the cell phone protocols
• requirement is for future development
• In case of future decision for work with any phone then the bandwidth will be adapted.
• The more difficult here is application coding to match some of existing formats.

4. Current status:

• I am reading the Sensor Tag stack firmware and I am preparing myself to write my own application.
• I am expecting you to help me with audio application to speed the time to the market.

Thank You in advance for understanding and the help!

Regards!

Milen

Hi,

Currently I am preparing to merge:

Sensor Controller Studio example: Analog Light Sensor

Here the ADC is in use, with Semaphore system.

With,

Code Composer Studio: Sensor Tag.

Here Bluetooth is working.

I hope to get this way my microphone firmware.

I will be very thankful if you have some advices for me.

As I mention before this is not cellphone project, but since you advised me to check my cellphone: 

It is 8 cores Lenovo with Android 4. The Sensor Tag demo application is working perfect on it.

M.Sc.Eng. Milen Moussakov

26.Sep.2015

Hi Milen,

I'm not sure I understand your question. Can you re-state it?

Hi JSX and Sean2,

I still am expecting help to create an audio application for CC2640 based on

Texas Instruments Audio examples like A2DP, and SensorTag - LED AUDIO.

I still wonder, you do not understand the last text or all the texts which we exchange from the beginning

of this post.

Best Regards!

Milen

Hi Milen,

There is no out of the box audio examples for the SensorTag at this time. Please note that A2DP is a Bluetooth Classic profile and doesn't apply to BLE devices.

A PDM driver has already been released in this revision of TI-RTOS[2.15.00.17], you can base your application code on that.