Sending a string over BLE using a characteristic

[Sudeep R J]

Hello,

I want to develop a data transfer service which has a control characteristic that is used to write commands on the phone app and if the command matches any command in the command list the corresponding response (a string) is sent over another characteristic that will be a notify characteristic.

I saw many posts on Devzone regarding this and all those posts mention about the same ble uart example. I am not able to run this example on my board as there is a RAMcode error that pops up whenever i try to download and debug this example. I also have some doubts regarding this that is there are the uart initialization functions in the code so does it involve the uart to send and receive the data? and in ble_nus_data_send() function there is a call for blcm_link_ctx_get(), I want to know what the uart is doing in this program? also about the role of blcm_link_ctx_get() function which is checked before updating hvx_params.

Is there any other way to do what i want to do? i dont want to involve uart or anything else. I just want to have to characteristics which have the necessary properties.

Kindly help me through!!

Thank you

[awneil]

Nordic 'Getting Started' resources:

https://www.nordicsemi.com/Get-Started

https://devzone.nordicsemi.com/nordic/short-range-guides/b/getting-started/posts/introduction-to-bluetooth-low-energy-and-ble-devel

Sudeep R J said:

I saw many posts on Devzone regarding this and all those posts mention about the same ble uart example

Yes - that is the one to look at!

https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v15.3.0/ble_sdk_app_nus_eval.html

Sudeep R J said:

there is a RAMcode error that pops up whenever i try to download and debug this example

Post a screenshot of what pops up.

https://devzone.nordicsemi.com/f/nordic-q-a/49995/twi-nrf52dk-ble/199526#199526

Are you building the example from source, or just using the pre-built Hex?

How, exactly, are you downloading?

Have you loaded the SoftDevice?

What target hardware are you using?

Sudeep R J said:

Is there any other way to do what i want to do?

Yes - the NUS example is a great place to start.

Sudeep R J said:

i dont want to involve uart or anything else

I strongly suggest that you start with the example as-is, and spend time studying it to see how the data is passed to & from BLE.

Once you understand that, you can easily modify it to take data from anywhere else.

If you then want to go on and create your own custom Services & Characteristics, follow these tutorials:

https://devzone.nordicsemi.com/nordic/short-range-guides/b/bluetooth-low-energy/posts/ble-services-a-beginners-tutorial

https://devzone.nordicsemi.com/nordic/short-range-guides/b/bluetooth-low-energy/posts/ble-characteristics-a-beginners-tutorial

[Sudeep R J]

Hey Awneil, 

Thanks for your quick response. The target hardware I am using is the BL651 from Laird which has a nRF52810.

The attached Screenshot shows the error that pops up when I try to erase memory using IAR embedded workbench. The general protocol that I follow Debug any program on IAR is to erase memory, download respective hex file and then go for download and debug.

Do you have any fix for this?

Waiting for your reply.

[awneil]

Sorry, I am not familiar with IAR - I have no idea what it's talking about there with "RAMCode".

You will find that IAR is a "minority interest" here - so support here will be limited.

Perhaps you should contact IAR about that?

If you're trying to load the code into RAM, that won't work - it's designed to go into Flash.

Sudeep R J said:

The target hardware I am using is the BL651 from Laird

I would strongly recommend that you start with a Nordic Dev Kit - that way you will get proven, ready-to-use examples and people here will be familiar with the Target and able to help you easily.

Use the Nordic Dev Kit to gain familiarity with the product and the tools.

Once you are familiar with the product and the tools, then is the time to move onto 3rd-party modules.

Alternatively, go to Laird for specific support and examples with their product.

Again, Nordic 'Getting Started' resources:

https://www.nordicsemi.com/Get-Started

https://devzone.nordicsemi.com/nordic/short-range-guides/b/getting-started/posts/introduction-to-bluetooth-low-energy-and-ble-devel

[Sudeep R J]

Hey Awneil,

Thats right. I have already worked with nRF52832 DK and i have tried the blinky example on that. I have also written characteristics for writing a byte of data and some thing like that. I want to know how to send data from my program to a phone app using a characteristic and thats it.

Does Segger embedded studio need any license to try out these examples?

Also can you explain me what the ble app uart program does as i am unable to run and debug it for myself. It would be really kind of you if you could help me in this. I want to know what is the role of UART in this? I mean how is data exchange taking place between BLE and phone app?

Thanks & regards

Sudeep R J 

[awneil]

Sudeep R J said:

Does Segger embedded studio need any license to try out these examples

No.

But you can get a free licence for using it with Nordic products:

https://www.segger.com/news/segger-embedded-studio-ide-now-free-for-nordic-sdk-users/

Sudeep R J said:

Also can you explain me what the ble app uart program does as i am unable to run and debug it for myself

It is described in the link I posted earlier.

[Sudeep R J]

Yea thanks for that link. I got to know the reason why i am getting that RAMcode error. Its because i am dumping it on softdevice s112 where as it is only for s132 and s140.

I will try to port it to s112. Do you think it is possible? 

[awneil]

Great - so that's answered the question for this thread.

So please verify the answer:

See this for porting to nRF52810:

https://devzone.nordicsemi.com/f/nordic-q-a/33812/developing-for-nrf52810---the-full-story

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