STM32WB55 MTU SIZE

[EBard.1]

I am currently working with the STM32WB55RGV6 MCU and utilizing the BLE functionality provided in the BLE_p2pserver example (STM32Cube_FW_WB_V1.18.0) from ST. However, I am facing a limitation where the data packet size is restricted to 20 bytes, preventing me from sending larger amounts of data.

I have come across forums suggesting that the MTU size can be increased to enable higher data throughput. However, I am not very experienced in writing or modifying the software, and I need step-by-step guidance to implement this change correctly.

I also found Application Note AN5289 and investigated the section on "How to maximize data throughput". While the document provides suggestions, I am unsure how to apply them to my code.

Could you please provide clear, step-by-step instructions on how to:

1. Increase the BLE MTU size,
2. Apply the recommendations from AN5289 to maximize the BLE throughput,
3. Make the necessary modifications to the BLE_p2pserver example?

Your help would be greatly appreciated, as I am currently stuck on this issue.

Thank you!

[STTwo-32]

Hello @EBard.1 

1) You can increase the MTU size throw the #define CFG_BLE_MAX_ATT_MTU on the app_conf.h file. 

2+3) to understand how those recommendations work, you can take a look at the  BLE_DataThroughput.

Best Regards.

STTwo-32

[EBard.1]

Hi,
Thank you,
Currently I am using BLE_p2p example provided by ST. 

I found that forum, should I go over these suggestions? Is there anything to add on these suggestions? 
https://community.st.com/t5/stm32-mcus-wireless/aci-gatt-update-char-value-ext-issue/td-p/652328

Should I add these?:
* hci_le_set_data_length
* hci_le_set_phy

Can you guide me like on the link please? Thank you. 

[STTwo-32]

Hello @EBard.1 

I think that following the recommendations of my answer on the last post should do the job. 

Best Regards.

STTwo-32

[EBard.1]

Hi,

Should I add these functions, what do you think?

* hci_le_set_data_length
* hci_le_set_phy

Thank you for your answers!

[STTwo-32]

I don't think so. But you could try.

Best Regards.

STTwo-32

[EBard.1]

Thank you again, for that function:

aci_gatt_update_char_value_ext(0x0000, aPeerToPeerContext.PeerToPeerSvcHdle, aPeerToPeerContext.P2PNotifyServerToClientCharHdle, 0x00, 509, 0, 243, (uint8_t *) pPayload);

Should I use 0x0000 adress for the Update_Type ? 

[STTwo-32]

 This parameter depends on the client(s) you want to select to be notified.

Best Regards.

STTwo-32