hi,
im using nrf5340 controller (central) to get measurement reading from multiple medical instruments (peripheral) simultaneously. everything work as expected. however, we face the connection failure often during the connection phase between the central and the peripheral stating "failed to establish. RF noise? connection failure due to 0x3E". the issues arises even if the peripheral is placed too close to the central. the central retires the connection with the peripheral and succeeds after multiple trials. we face the issue rarely using the Nordic nrf5340 dk board and more frequently with the custom board that we have developed. we are using Raytec MDBT53-DB custom chip in out board. we have cross checked with the crystal specification, we have used EPSON 32.768 khz crystal with 10ppm resolution.
Function connected (callback) called with no error (Possible) connected periph address: 00:A0:50:20:CD:51 (public) (type: Set connected packets Tx power level to max value (+3dBm) [00:00:39.501,953] <wrn> bt_hci_core: opcode 0xfc0e status 0x01 Set Tx power err: -5 berry Pulse Ox) Sending binary data: 08 04 00 a0 50 20 cd 51 Refreshing scanning Starting scanning [00:00:39.781,585] <wrn> bt_conn: conn 0x200017d8 failed to establish. RF noise? Function disconnected (callback) called Failed to establish connection (0x3E disconnect) with device: 00:A0:50:20:CD:51 (public) (type: berry Pulse Ox) Sending binary data: 08 05 00 a0 50 20 cd 51 Refreshing scanning Bond deleted; id: 0, peer addr: 00:A0:50:20:CD:51 (public) berry Pulse Oximeter Filter Detected! Address:00A05020CD51 Function connected (callback) called with no error (Possible) connected periph address: 00:A0:50:20:CD:51 (public) (type: Set connected packets Tx power level to max value (+3dBm) [00:00:40.099,456] <wrn> bt_hci_core: opcode 0xfc0e status 0x01 Set Tx power err: -5 berry Pulse Ox) Sending binary data: 08 04 00 a0 50 20 cd 51 Refreshing scanning Starting scanning [00:00:40.381,591] <wrn> bt_conn: conn 0x200017d8 failed to establish. RF noise? Function disconnected (callback) called Failed to establish connection (0x3E disconnect) with device: 00:A0:50:20:CD:51 (public) (type: berry Pulse Ox) Sending binary data: 08 05 00 a0 50 20 cd 51 Refreshing scanning Bond deleted; id: 0, peer addr: 00:A0:50:20:CD:51 (public) berry Pulse Oximeter Filter Detected! Address:00A05020CD51 Function connected (callback) called with no error (Possible) connected periph address: 00:A0:50:20:CD:51 (public) (type: Set connected packets Tx power level to max value (+3dBm) [00:00:40.813,842] <wrn> bt_hci_core: opcode 0xfc0e status 0x01 Set Tx power err: -5 berry Pulse Ox) Sending binary data: 08 04 00 a0 50 20 cd 51 Refreshing scanning Starting scanning
what cause such issue how can we identify the cause of the issue and is it based on the hardware or can it be handled by the software.