I experiment connection problems on a nRF52 board with a Samsung J3 (Android 5.1).
To sort out this problem, I made some tests with the nRF52-DK (PCA10040), the Heart Rate Sensor example (ble_app_hrs) and the nRF Connect application. Here are the results:
I check the Heart Rate Sensor example with success with:
I have an older project with an nRF51, SDK 8.1, S130-SD-v1.0.0 and the Samsung J3 can connect the device without problem !
I see some posts about Samsung (J1) connections problem but no one corresponds to my problem.
Did you know about this regression? Does it have a solution?
I can make (almost) any test to help finding the solution!
Thanks for you help.
Could you try to capture a sniffer trace ?
The new compatibility mode on the S132v3.1.0 is only enabled after you call sd_ble_opt_set() with BLE_GAP_OPT_COMPAT_MODE_2 ID and mode_2_enable = 1. Please check the ble_gap.h header in S132v3.1.0.
Ah ok, I miss the BLE_GAP_OPT_COMPAT_MODE_2. I will try that right now.
If I was unsuccessful, I will capture a sniffer trace (which I have COM connection problem too!).
I use the compatibility mode on the S132v3.1.0 with success on the Heart Rate Sensor example.
I will validate your answer after the correction of my real project.