Wireless MCUのトピックRe: BLE sample code issue with custom services

BLE sample code issue with custom services

Chan_17 — Thu, 05 Jun 2025 12:31:32 GMT

we are trying KW45 wireless example EATT freertos example and we are trying to modify data in the functiuon ServiceAMeasurementTimerCallback() but we are getting issue with whatever data we are writing to database which is not reflecting in central device, we are getting initialized data in gatt_db.h . screenshots are attached . we are just getting initialized value (gatt_db.h) but its not updating with the data we are writing to database.
as per screenshot we are trying to write data of array but in central we are getting 0x41 i,e A data and rest 9 bytes are 0.

Re: BLE sample code issue with custom services

sofiaurueta — Thu, 05 Jun 2025 19:44:36 GMT

Hello,

Hope you are doing well.

Can you help letting me know what SDK and MCUXpresso IDE versions you are using?

Also, could you be more specific in what modifications you implemented in the code?

I would recommend checking this community post: KW38 Custom Profile - NXP Community, as well as Chapter 7 “Creating a GATT Database” of the Bluetooth Low Energy Application Developer’s Guide.

There you can find a brief description of the services and the declarations needed.

Best Regards,

Ana Sofia.

Re: BLE sample code issue with custom services

Chan_17 — Fri, 06 Jun 2025 07:24:09 GMT

Please check Versions below
SDK : KW45b41zevk
MCUXpresso : 24.12

modifications we did :
in ServiceBMeasurementTimerCallback()
bleUuid_t uuid = Uuid16(gBleSig_Report_d); changed to bleUuid_t uuid = Uuid16(0xB002); because we are checking for char_service_B2
static uint16_t char_value = 0U; changed to static uint16_t char_value = 12U;

and even we tried with same UUID : bleUuid_t uuid = Uuid16(gBleSig_Report_d); and just changed changed to static uint16_t char_value = 12U;
same issue just we are getting data which is initialized

Re: BLE sample code issue with custom services

sofiaurueta — Mon, 09 Jun 2025 15:47:38 GMT

Hello,

In order to create the demo you need to define or develop a service that has to be the same as in the GATT Client, this is declared in the gatt_uuid128.h. If the new service is not the same, they will never be able to communicate each other.

All the macros used to fill the GATT database are properly described in the BLEADG (included in the NXP Connectivity Software documentation) under chapter 7 “Creating a GATT Database”.

Could you let me know if you implemented these services and modifications in both client and server sides?

You can follow the steps to this community post: KW38 Custom Profile

Best Regards,

Ana Sofia.

Re: BLE sample code issue with custom services

Chan_17 — Wed, 11 Jun 2025 05:04:26 GMT

Hi,

we tried to do changes in peripheral by updating new service and also tried to use old custom service to send bulk data.
example: Eatt_peripheral freertos we specifically used this since its sending multiple packets. we are searching for example in which we can send bulk data and multiple packets.
1. we tried sending different 2 bytes of data from eatt_peripheral and we are checking in NRF connect but we are not getting any changed data.

2. so we tried with 2 KW45 boards one for central and another peripheral . in this if we change data which is writing to database is reflecting in central but when we try for bulk data or array of data even after doing changes in below section :

1.we changed size of data required 10 bytes, using 0xB002 service B2

these modifications we did. please check and assist we are not able to receive this in central