multilink db discovery gives discovery response multiple times for 1st ble connection after reset.

[nikunj8086]

hi,

i am doing a project where i have to discover custom services on connected ble nodes.

i am using nrf52832 as central device and thingy 52 as peripheral device i have used sdk 14.2.0 multilink central example and modified it to discover all custom services.

so far i am able to discover all custom services if value of "NRF_SDH_BLE_CENTRAL_LINK_COUNT" is 1.but when i changed it's value to more then 1(i have used 2,4,8) i am getting these massages of system fault on uart terminal

<error> app: Fatal error
<warning> app: System reset

when debug and put uart output on terminal  with original example i figured that on first connection after program starts service discovery response event is generated same number of times as NRF_SDH_BLE_CENTRAL_LINK_COUNT and that causes above error.

is there any way to stop  multiple discovery event for first connection after reset.

thanks

[Hung Bui]

Hi Nikunj, 

 

Could you point to the exact place that the error was thrown ?  Which function ? 

Do you have the same issue when you test with 2 peripheral + 1 central running lbs service ? 

[nikunj8086]

hi hung bui,

so i am getting error code 0x00000011 by calling api "sd_ble_gattc_read" to read full 128-bit base uuid.

basically i am doing full db discovery by providing argument ble_uuid_t const *p_srvc_uuid = NULL in sd_ble_gattc_primary_services_discover API.

but my question is that why i am getting number of  BLE_GATTC_EVT_PRIM_SRVC_DISC_RSP event same as number of NRF_SDH_BLE_CENTRAL_LINK_COUNT.

so in default ble_central_multilink example NRF_SDH_BLE_CENTRAL_LINK_COUNT is 8 so i am getting BLE_GATTC_EVT_PRIM_SRVC_DISC_RSP event 8 times.

but if BLE_GATTC_EVT_PRIM_SRVC_DISC_RSP is 1 my program works fine.

 is there any way to reduce BLE_GATTC_EVT_PRIM_SRVC_DISC_RSP to 1

thanks

[Hung Bui]

Error code 0x11 (17 decimal = NRF_ERROR_BUSY) with sd_ble_gattc_read() telling that there is other client process underway. 

Note that for every central link you have, there will be a lbs client being created. Are you sure you are not calling ble_db_discovery_start() for all of the clients you have, regardless how many connection you actually have ? 

Do you see the same error when you test with unmodified multilink central example ? 

 

[nikunj8086]

hi,

i have 8 connections,

but i am sure i am only starting ble_db_discovery_start for connection handle 0 only.

when i put a nrf log info in BLE_GATTC_EVT_PRIM_SRVC_DISC_RSP and commented other process.

i got this response on terminal

info> app: Multilink example started.
<info> app: Start scanning for device name Thingy.
<info> app: Connection 0x0 established, starting DB discovery.
<info> app: Start scanning for device name Thingy.
<info> ble_db_disc: connection handle 0 service found 0x1800
<info> ble_db_disc: connection handle 0 service found 0x1800
<info> ble_db_disc: connection handle 0 service found 0x1800
<info> ble_db_disc: connection handle 0 service found 0x1800
<info> ble_db_disc: connection handle 0 service found 0x1800
<info> ble_db_disc: connection handle 0 service found 0x1800
<info> ble_db_disc: connection handle 0 service found 0x1800
<info> ble_db_disc: connection handle 0 service found 0x1800

when i connected 4 nodes following response i got

<info> app: Connection 0x3 established, starting DB discovery.
<info> app: Start scanning for device name Thingy.
<info> ble_db_disc: connection handle 0 service found 0x1800
<info> ble_db_disc: connection handle 1 service found 0x1800
<info> ble_db_disc: connection handle 2 service found 0x1800
<info> ble_db_disc: connection handle 3 service found 0x1800
<info> ble_db_disc: connection handle 0 service found 0x1800
<info> ble_db_disc: connection handle 0 service found 0x1800
<info> ble_db_disc: connection handle 0 service found 0x1800
<info> ble_db_disc: connection handle 0 service found 0x1800

when i connected 8 nodes i got following response

<info> app: Connection 0x7 established, starting DB discovery.
<info> ble_db_disc: connection handle 0 service found 0x1800
<info> ble_db_disc: connection handle 1 service found 0x1800
<info> ble_db_disc: connection handle 2 service found 0x1800
<info> ble_db_disc: connection handle 3 service found 0x1800
<info> ble_db_disc: connection handle 4 service found 0x1800
<info> ble_db_disc: connection handle 5 service found 0x1800
<info> ble_db_disc: connection handle 6 service found 0x1800
<info> ble_db_disc: connection handle 7 service found 0x1800

please tell me what is happening here. either way i am getting 8 times response

is this problem with softdevice or my code.?

[Hung Bui]

Please answer my question, do you see the same problem when testing with the stock example ? 

[nikunj8086]

yes,

in stock example i am getting 8 times response 

[Hung Bui]

Hi Nikunj, 

Actually it's known bug. You can have a look at this case to find the fix.

Sorry that I didn't spot that at the beginning. 

However, it might not the direct cause of the error you see. But please apply the fix to main() and let me know if you still have the issue.