LP-EM-CC2340R5: Scan request for advertisers from central device

Hello,

Thank you for reaching out! To do this, you will need to set the filter policy to SCAN_FLT_POLICY_AL. I've also included a link to the filter policy options below.

https://dev.ti.com/tirex/explore/content/simplelink_lowpower_f3_sdk_8_40_02_01/docs/ble5stack/ble_user_guide/doxygen/ble/html/group___gap_scan___structs.html#ga5be84ddb41dcf5fd6ba2e5e1fda1b2b3

I hope this helps!

Best Regards,

Tarek

Hello,

Thanks for clarifying! From what you're describing, it seems like you would like the central to passively scan, until it scans an advertisement from the accept list. Unfortunately, the BLE stack does not have a conditional active scanning option (It is not specified in the BLE spec).

One way to achieve your desired behavior is to initially set the central to passively scan, then, upon scanning the advertisement of the desired device, add the device's address to the acceptlist. Afterwards, dynamically set the device to perform active scanning using filter policy: SCAN_FLT_POLICY_AL

To do this:

1. Go to the Sysconfig file of the project
2. Inside the BLE menu, scroll down and select Observer Configuration
3. Set "Scan Type" to Passive
4. Go to app_central.c file
5. Add the following event to the centralScanHandler event handler:
   

   BLEAppUtil_EventHandler_t centralScanHandler =
   {
       .handlerType    = BLEAPPUTIL_GAP_SCAN_TYPE,
       .pEventHandler  = Central_ScanEventHandler,
       .eventMask      = BLEAPPUTIL_SCAN_ENABLED |
                         BLEAPPUTIL_SCAN_DISABLED |
                         BLEAPPUTIL_ADV_REPORT // ADD THIS
   };

6. Scroll down to the Central_ScanEventHandler() and add a case for the BLEAPUTIL_ADV_REPORT as follows:
   

   case BLEAPPUTIL_ADV_REPORT:
   {
       bleStk_GapScan_Evt_AdvRpt_t *pScanRpt = &scanMsg->pBuf->pAdvReport;
       if (pScanRpt->pData != NULL)
       {
           uint8_t indx = 0;
           for (; indx < pScanRpt->dataLen; indx++)
           {
               MenuModule_printf(APP_MENU_SCAN_EVENT + indx, 0, "Data: %d", pScanRpt->pData[indx]);
           }
       }
       break;
   }

7. Process pScanRpt->addr (which is the address of each advertiser that was scanned) as you wish, and when you find the device address that you would like to add to the accept list, use the function HCI_LE_AddAcceptListCmd() to dynamically add the address to the accept list.
8. Set the filter policy to SCAN_FLT_POLICY_AL using GapScan_SetParams()
   
9. Set the scanning type to active by using GapScan_setPhyParams()

For more info on our Scanning and Advertising, please check out our SimpleLink Academy Trainings found in the link below:
dev.ti.com/.../node

I hope this answers you question!

Best Regards,

Tarek

Hello,

Thank you for clarifying! Unfortunately, there isn't a specific process described by the BLE spec to achieve this behavior. One thing that you can possibly attempt to do is to follow the procedure I included above, then, upon establishing a connection with the device that you have added to the accept list, dynamically change the filter policy back to SCAN_FLT_POLICY_ALL, and change the scanning type back to passive, until you see another address you'd like to add to the accept list.

I hope this helps!

Best Regards,

Tarek