Serialization (connectivity software.)

[josantoniojl]

Hi everybody,

I have been reading the serialization documentation (infocenter.nordicsemi.com/index.jsp and I am not very clear about some points.

• What is it for and what should it contain the firmware connectiviy? 
• If i create my own GATT service this will be working in the "Codec step"?

Best regards, 

Jose Lopez

[tesc]

Hi,

The serialization is for if you want our SoftDevice (BLE stack) to run on one microcontroller (MCU), but the application (calling the SoftDevice API) running on a different MCU.

GATT services are on the Application layer.

If you want to run everything on a single nRF MCU, then you should not use serialization at all, but rather just call the SoftDevice API directly.

Also, if you do need to split your product in two, using an nRF as network chip, it often makes more sense to write a BLE application on the nRF, with a higher-level serial interface than what SoftDevice serialization gives you. That way you do not need to re-implement the BLE related SDK libraries on the other MCU. If that other MCU is an nRF, then you should probably rather use a more powerful nRF MCU in the first place, and use the SoftDevice directly.

Regards,
Terje

[josantoniojl]

Hi, 

Thank you for your answer.

I will use the NRF as coprocessor. The principal one is an stm32 processor.

And yes at the beginning I thought write a BLE application on the nRF. But reading the documentation the recommendation is to serialize the SoftDevice.

But I’m still having the same doubt, in the documentation its says :

In addition to the SoftDevice, the connectivity chip must be programmed with the connectivity software. You can find the source code and the project file of the example in the following folder: <InstallFolder>\examples\connectivity (select the project for the protocol that you want to use).

So, I wanted to know, what to write in the connectivity software. And if the GATT will be used in the connectivity chip.

Can you answered me these two questions?

Also, in terms of performance it will be better to write a BLE application on the nRF?

BR

José

[tesc]

Hi,

josantoniojl said:

So, I wanted to know, what to write in the connectivity software.

The connectivity software can be used almost directly. You may have to configure UART pins and clock source (if it differs from the defaults used for the DK project.)

josantoniojl said:

And if the GATT will be used in the connectivity chip.

I am afraid I do not quite understand what you mean. GATT is part of the BLE stack, and the SoftDevice has an API for working with GATT both as server and client.

josantoniojl said:

Also, in terms of performance it will be better to write a BLE application on the nRF?

Probably yes. The nRF series SoCs do have enough resources to run more than just the stack. It would free up some resources on the main MCU, and reduce the amount of data transfer over the serial interface. Also it means you can use libraries from our SDK for handling e.g. bonding.

That being said, my best advice is to look at the options, what the SoftDevice API provides, what our SDK adds in terms of BLE related libraries, and what you need for your product. Then decide whether to use the SoftDevice API directly from the main MCU, or to implement some of the BLE application layer on the nRF, and rather use your own serial protocol for exchanging the necessary information between main MCU and nRF. Both are viable options.

Regards,
Terje