MAX32666 BLE occasionally times out after multiple back-to-back RX errors with RPi5 Linux/BlueZ and default supervision timeout of 420ms

[khpeterson]

Version: 6d91b0e99fa7924ac91ae8a07b77caac0d5ba201 (branch in my fork = origin/main + #1507 + #1502 + #1501)

Environment: Running repeats of modified BLE_FreeRTOS application on a vanilla MAX32666FTHR with continuous characteristic notifications (high-rate or slow, doesn't matter) sent to a Raspberry Pi 5 Debian (trixie) BlueZ Host with WiFi disabled. Host and peripheral are separated by about 9 inches so the channel is NOT impaired.

Console log and Wireshark trace below.

On ~3% of connections (e.g 50 / 1847 overnight), the MAX32666 peripheral app will report a sequence of back-to-back RX errors ( RX_TIMEOUT or CRC_FAILED) and then terminate with SUP_TIMEOUT. The default Linux/BlueZ configured timeout is 420ms so it takes about 8 consecutive RX errors to cause the SUP_TIMEOUT.

Another extended run of repeats with the supervision timeout configured to 72 (720ms) resulted in no timeouts, though there are multiple occurrences of 8+ back-to-back RX errors, just none longer than the 720ms timeout window.

So, bottom line, the default Linux timeout of 420ms is too short for the MAX32666 to connect/communicate reliably with RPi5. And for what it's worth, substituting with a Qualcomm based Ubuntu 24.04 BlueZ host (Particle Tachyon) is clean at 420ms so this appears to be specific to the RPi5 BLE PHY. And substituting a Realtek RTL8721DM based BLE peripheral is also clean.

This problem looks similar to the behavior of #1500 where transmitter appears to stop and all packets received from then on have errors. But in this case there is no PHY update in the picture.

Any known issues with the MAX32666 BB/PHY that would explain the large error bursts?

One more observation - other peripheral devices use a longer supervision timeout despite the host request of 420ms. I wonder if that might be a good solution here. I will test it out and if it works, create a PR.

Here is the console log but with the middle clipped once notifications start streaming:

2026-01-20T17:23:23.930510: lctrSlvAdvExecuteSm: state=1, event=4
2026-01-20T17:23:23.937690: lctrSlvConnExecuteSm: handle=0, state=INITIALIZED, event=RX_CONNECT_IND
2026-01-20T17:23:23.942437: lctrSlvConnBuildOp: interval:39, latency:0, timeout:42, txWinSize: 3
2026-01-20T17:23:23.946255: >>> Connection established, handle=0 <<<
2026-01-20T17:23:23.952096: connIntervalUsec=48750
2026-01-20T17:23:23.955132: dueUsec=6582517
2026-01-20T17:23:23.959331: minDurUsec=4604
2026-01-20T17:23:23.962687: Topology Add, handle=0, interval_ms=48
2026-01-20T17:23:23.966070: Topology Add,            durUsec=806
2026-01-20T17:23:23.971334: lctrLlcpExecuteCommonSm: handle=0, proc=4, state=IDLE, event=1
2026-01-20T17:23:23.975559: ### LlEvent ###  LL_CONN_IND, handle=0, status=0
2026-01-20T17:23:23.981552: ### LlEvent ###  LL_CH_SEL_ALGO_IND, handle=0, status=0, usedChSel=0
2026-01-20T17:23:23.983923: dmConnIdByBdAddr not found
2026-01-20T17:23:23.985426: dmConnCcbAlloc 1
2026-01-20T17:23:23.988305: dmConnSmExecute event=28 state=0
2026-01-20T17:23:23.990553: dmAdvConnected: state: 1
2026-01-20T17:23:23.995553: dmDevPassEvtToDevPriv: event: 13, param: 34, advHandle: 0
2026-01-20T17:23:23.997802: AttsCccInitTable connId=1
2026-01-20T17:23:24.000807: smpDbGetRecord: connId: 1 type: 0
2026-01-20T17:23:24.002170: smpDbAddDevice
2026-01-20T17:23:24.005808: SmpDbGetFailureCount: connId: 1 count: 0
2026-01-20T17:23:24.008678: smpDbGetRecord: connId: 1 type: 0
2026-01-20T17:23:24.010058: smpDbAddDevice
2026-01-20T17:23:24.015687: SmpDbGetPairingDisabledTime: connId: 1 period: 0 attemptMult: 0
2026-01-20T17:23:24.016925: Ble got evt 39
2026-01-20T17:23:24.020810: ### LlApi ###  LlReadRemoteFeat, handle=0
2026-01-20T17:23:24.022930: >>> Connection opened <<<
2026-01-20T17:23:24.028429: lctrLlcpExecuteCommonSm: handle=0, proc=2, state=BUSY, event=0
2026-01-20T17:23:24.032171: Pending procedure in progress: activeProc=4
2026-01-20T17:23:24.033924: 20486840: enabling
2026-01-20T17:23:24.036047: connId=1 idleMask=0x0000
2026-01-20T17:23:24.041561: lctrLlcpExecuteCommonSm: handle=0, proc=2, state=BUSY, event=4
2026-01-20T17:23:24.046920: Procedure collision; pending incomplete request, activeProc=4
2026-01-20T17:23:24.055174: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=22, eventCounter=1
2026-01-20T17:23:24.087476: 20487000: tick
2026-01-20T17:23:24.105420: lctrLlcpExecuteCommonSm: handle=0, proc=4, state=BUSY, event=5
2026-01-20T17:23:24.110420: ### LlEvent ###  LL_DATA_LEN_CHANGE_IND, handle=0, status=0
2026-01-20T17:23:24.114043: Effective data lengths maxTxLen=251, maxRxLen=251
2026-01-20T17:23:24.118670: Effective data times maxTxTime=2120, maxRxTime=2120
2026-01-20T17:23:24.124053: lctrLlcpExecuteCommonSm: handle=0, proc=2, state=IDLE, event=1
2026-01-20T17:23:24.125418: Ble got evt 65
2026-01-20T17:23:24.155314: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=18, eventCounter=4
2026-01-20T17:23:24.202186: lctrLlcpExecuteCommonSm: handle=0, proc=4, state=BUSY, event=4
2026-01-20T17:23:24.207432: Procedure collision; pending incomplete request, activeProc=2
2026-01-20T17:23:24.211925: Effective data lengths maxTxLen=251, maxRxLen=251
2026-01-20T17:23:24.216302: Effective data times maxTxTime=2120, maxRxTime=2120
2026-01-20T17:23:24.248098: attsProcMtuReq features 0x00
2026-01-20T17:23:24.250191: hciCoreTxAclStart len=7
2026-01-20T17:23:24.251573: Ble got evt 22
2026-01-20T17:23:24.299727: lctrLlcpExecuteCommonSm: handle=0, proc=2, state=BUSY, event=5
2026-01-20T17:23:24.305058: ### LlEvent ###  LL_READ_REMOTE_FEAT_CNF, handle=0, status=0
2026-01-20T17:23:24.306303: Ble got evt 87
2026-01-20T17:23:24.345521: hciCoreTxAclStart len=9
2026-01-20T17:23:24.399107: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=36, eventCounter=9
2026-01-20T17:23:24.491793: hciCoreTxAclStart len=24
2026-01-20T17:23:24.588881: hciCoreTxAclStart len=9
2026-01-20T17:23:24.691836: lctrSlvConnRxCompletion: BB failed with status=CRC_FAILED, handle=0, bleChan=28, eventCounter=15
2026-01-20T17:23:24.735555: hciCoreTxAclStart len=9
2026-01-20T17:23:24.789221: lctrSlvConnRxCompletion: BB failed with status=CRC_FAILED, handle=0, bleChan=13, eventCounter=17
2026-01-20T17:23:24.837950: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=24, eventCounter=18
2026-01-20T17:23:24.984650: lctrSlvConnRxCompletion: BB failed with status=CRC_FAILED, handle=0, bleChan=20, eventCounter=21
2026-01-20T17:23:25.032971: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=31, eventCounter=22
2026-01-20T17:23:25.076611: connId 1 updated csf to 0x05
2026-01-20T17:23:25.082257: hciCoreTxAclStart len=5
2026-01-20T17:23:25.083538: 20488000: tick
2026-01-20T17:23:25.175960: attsCccMainCback connId=1 handle=19
2026-01-20T17:23:25.183452: Ble got evt 20
2026-01-20T17:23:25.184337: ccc state ind value:2 handle:19 idx:0
2026-01-20T17:23:25.184666: hciCoreTxAclStart len=5
2026-01-20T17:23:25.229791: lctrSlvConnRxCompletion: BB failed with status=CRC_FAILED, handle=0, bleChan=1, eventCounter=26
2026-01-20T17:23:25.280280: lctrSlvConnRxCompletion: BB failed with status=CRC_FAILED, handle=0, bleChan=12, eventCounter=27
2026-01-20T17:23:25.374323: lctrSlvConnRxCompletion: BB failed with status=CRC_FAILED, handle=0, bleChan=34, eventCounter=29
2026-01-20T17:23:25.419694: attsCccMainCback connId=1 handle=5379
2026-01-20T17:23:25.421878: Ble got evt 20
2026-01-20T17:23:25.423703: ccc state ind value:1 handle:5379 idx:2
2026-01-20T17:23:25.425806: hciCoreTxAclStart len=5
2026-01-20T17:23:25.427559: 20488335: starting
2026-01-20T17:23:25.429719: connId=1 idleMask=0x0010
2026-01-20T17:23:25.432088: hciCoreTxAclStart len=179
2026-01-20T17:23:25.433461: Ble got evt 18
2026-01-20T17:23:25.449591: hciCoreTxAclStart len=178
2026-01-20T17:23:25.450599: Ble got evt 18
.
.
.
2026-01-20T17:23:29.499631: hciCoreTxAclStart len=176
2026-01-20T17:23:29.501276: Ble got evt 18
2026-01-20T17:23:29.518130: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=9, eventCounter=114
2026-01-20T17:23:29.532389: Ble got evt 18
2026-01-20T17:23:29.560019: flowDisabled=1 handle=0
2026-01-20T17:23:29.561953: hciCoreTxAclStart len=179
2026-01-20T17:23:29.564202: hciCoreTxAclStart len=180
2026-01-20T17:23:29.566326: flowDisabled=0 handle=0
2026-01-20T17:23:29.567705: Ble got evt 18
2026-01-20T17:23:29.591029: hciCoreTxAclStart len=179
2026-01-20T17:23:29.592027: Ble got evt 18
2026-01-20T17:23:29.615663: lctrSlvConnRxCompletion: BB failed with status=CRC_FAILED, handle=0, bleChan=29, eventCounter=116
2026-01-20T17:23:29.621497: hciCoreTxAclStart len=180
2026-01-20T17:23:29.622885: Ble got evt 18
2026-01-20T17:23:29.652104: Ble got evt 18
2026-01-20T17:23:29.664218: lctrSlvConnRxCompletion: BB failed with status=CRC_FAILED, handle=0, bleChan=3, eventCounter=117
2026-01-20T17:23:29.684024: flowDisabled=1 handle=0
2026-01-20T17:23:29.713502: lctrSlvConnRxCompletion: BB failed with status=CRC_FAILED, handle=0, bleChan=14, eventCounter=118
2026-01-20T17:23:29.763240: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=25, eventCounter=119
2026-01-20T17:23:29.811092: lctrSlvConnRxCompletion: BB failed with status=CRC_FAILED, handle=0, bleChan=36, eventCounter=120
2026-01-20T17:23:29.859404: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=10, eventCounter=121
2026-01-20T17:23:29.908985: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=21, eventCounter=122
2026-01-20T17:23:29.957116: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=32, eventCounter=123
2026-01-20T17:23:29.991026: lctrConnStatelessEventHandler: handle=0, state=2, event=SUP_TIMEOUT
2026-01-20T17:23:29.995968: lctrConnStatelessEventHandler: handle=0, state=3, event=TERMINATED
2026-01-20T17:23:29.998248: Topology Remove, handle=0
2026-01-20T17:23:30.004606: ### LlEvent ###  LL_DISCONNECT_IND, handle=0, status=LL_SUCCESS, reason=8
2026-01-20T17:23:30.008472: >>> Connection terminated, handle=0 <<<

And here is the Wireshark trace for the last 8 notifications + the 9 unanswered packets from the host before the peripheral times out. The first unanswered packet starts at Frame 6010:

Frame 5994: Packet, 201 bytes on wire (1608 bits), 201 bytes captured (1608 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6009
    Length of packet: 10
    Flags: 0x01
        .... ...1 = CRC: Ok
        .... ..0. = Direction: Peripheral -> Central
        .... .0.. = Encrypted: No
        .... 0... = MIC (not relevant): 0
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 11
    RSSI: -61 dBm
    Event counter: 111
    Timestamp: 257345640µs
    [Packet time (start to end): 1480µs]
    [Delta time (end to start): 150µs]
    [Delta time (start to start): 230µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..10 = LLID: Start of an L2CAP message or a complete L2CAP message with no fragmentation (0x2)
        .... .1.. = Next Expected Sequence Number: 1 [ACK]
        .... 0... = Sequence Number: 0 [OK]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 175
    [L2CAP Index: 1568]
    [Connection Parameters in: 5674]
    CRC: 0x1069a5
Bluetooth L2CAP Protocol
Bluetooth Attribute Protocol

Frame 5995: Packet, 26 bytes on wire (208 bits), 26 bytes captured (208 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6010
    Length of packet: 10
    Flags: 0x0b
        .... ...1 = CRC: Ok
        .... ..1. = Direction: Central -> Peripheral
        .... .0.. = Encrypted: No
        .... 1... = MIC (not relevant): 1
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 22
    RSSI: -55 dBm
    Event counter: 112
    Timestamp: 257390369µs
    [Packet time (start to end): 80µs]
    [Delta time (end to start): 43249µs]
    [Delta time (start to start): 44729µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..01 = LLID: Continuation fragment of an L2CAP message, or an Empty PDU (0x1)
        .... .1.. = Next Expected Sequence Number: 1 [ACK]
        .... 1... = Sequence Number: 1 [OK]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 0
    [Connection Parameters in: 5674]
    CRC: 0x23b029

Frame 5996: Packet, 202 bytes on wire (1616 bits), 202 bytes captured (1616 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6011
    Length of packet: 10
    Flags: 0x01
        .... ...1 = CRC: Ok
        .... ..0. = Direction: Peripheral -> Central
        .... .0.. = Encrypted: No
        .... 0... = MIC (not relevant): 0
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 22
    RSSI: -57 dBm
    Event counter: 112
    Timestamp: 257390599µs
    [Packet time (start to end): 1488µs]
    [Delta time (end to start): 150µs]
    [Delta time (start to start): 230µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..10 = LLID: Start of an L2CAP message or a complete L2CAP message with no fragmentation (0x2)
        .... .0.. = Next Expected Sequence Number: 0 [ACK]
        .... 1... = Sequence Number: 1 [OK]
        ...1 .... = More Data: True
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 176
    [L2CAP Index: 1569]
    [Connection Parameters in: 5674]
    CRC: 0xad3d3e
Bluetooth L2CAP Protocol
Bluetooth Attribute Protocol

Frame 5997: Packet, 26 bytes on wire (208 bits), 26 bytes captured (208 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6012
    Length of packet: 10
    Flags: 0x0b
        .... ...1 = CRC: Ok
        .... ..1. = Direction: Central -> Peripheral
        .... .0.. = Encrypted: No
        .... 1... = MIC (not relevant): 1
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 22
    RSSI: -56 dBm
    Event counter: 112
    Timestamp: 257392237µs
    [Packet time (start to end): 80µs]
    [Delta time (end to start): 150µs]
    [Delta time (start to start): 1638µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..01 = LLID: Continuation fragment of an L2CAP message, or an Empty PDU (0x1)
        .... .0.. = Next Expected Sequence Number: 0 [ACK]
        .... 0... = Sequence Number: 0 [OK]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 0
    [Connection Parameters in: 5674]
    CRC: 0x8d6029

Frame 5998: Packet, 201 bytes on wire (1608 bits), 201 bytes captured (1608 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6013
    Length of packet: 10
    Flags: 0x01
        .... ...1 = CRC: Ok
        .... ..0. = Direction: Peripheral -> Central
        .... .0.. = Encrypted: No
        .... 0... = MIC (not relevant): 0
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 22
    RSSI: -54 dBm
    Event counter: 112
    Timestamp: 257392467µs
    [Packet time (start to end): 1480µs]
    [Delta time (end to start): 150µs]
    [Delta time (start to start): 230µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..10 = LLID: Start of an L2CAP message or a complete L2CAP message with no fragmentation (0x2)
        .... .1.. = Next Expected Sequence Number: 1 [ACK]
        .... 0... = Sequence Number: 0 [OK]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 175
    [L2CAP Index: 1570]
    [Connection Parameters in: 5674]
    CRC: 0x3c15ea
Bluetooth L2CAP Protocol
Bluetooth Attribute Protocol

Frame 5999: Packet, 26 bytes on wire (208 bits), 26 bytes captured (208 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6014
    Length of packet: 10
    Flags: 0x0b
        .... ...1 = CRC: Ok
        .... ..1. = Direction: Central -> Peripheral
        .... .0.. = Encrypted: No
        .... 1... = MIC (not relevant): 1
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 33
    RSSI: -56 dBm
    Event counter: 113
    Timestamp: 257439120µs
    [Packet time (start to end): 80µs]
    [Delta time (end to start): 45173µs]
    [Delta time (start to start): 46653µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..01 = LLID: Continuation fragment of an L2CAP message, or an Empty PDU (0x1)
        .... .1.. = Next Expected Sequence Number: 1 [ACK]
        .... 1... = Sequence Number: 1 [OK]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 0
    [Connection Parameters in: 5674]
    CRC: 0x23b029

Frame 6000: Packet, 206 bytes on wire (1648 bits), 206 bytes captured (1648 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6015
    Length of packet: 10
    Flags: 0x01
        .... ...1 = CRC: Ok
        .... ..0. = Direction: Peripheral -> Central
        .... .0.. = Encrypted: No
        .... 0... = MIC (not relevant): 0
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 33
    RSSI: -49 dBm
    Event counter: 113
    Timestamp: 257439350µs
    [Packet time (start to end): 1520µs]
    [Delta time (end to start): 150µs]
    [Delta time (start to start): 230µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..10 = LLID: Start of an L2CAP message or a complete L2CAP message with no fragmentation (0x2)
        .... .0.. = Next Expected Sequence Number: 0 [ACK]
        .... 1... = Sequence Number: 1 [OK]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 180
    [L2CAP Index: 1571]
    [Connection Parameters in: 5674]
    CRC: 0x9e5afa
Bluetooth L2CAP Protocol
Bluetooth Attribute Protocol

Frame 6001: Packet, 26 bytes on wire (208 bits), 26 bytes captured (208 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6016
    Length of packet: 10
    Flags: 0x0b
        .... ...1 = CRC: Ok
        .... ..1. = Direction: Central -> Peripheral
        .... .0.. = Encrypted: No
        .... 1... = MIC (not relevant): 1
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 9
    RSSI: -46 dBm
    Event counter: 114
    Timestamp: 257487871µs
    [Packet time (start to end): 80µs]
    [Delta time (end to start): 47001µs]
    [Delta time (start to start): 48521µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..01 = LLID: Continuation fragment of an L2CAP message, or an Empty PDU (0x1)
        .... .0.. = Next Expected Sequence Number: 0 [ACK]
        .... 0... = Sequence Number: 0 [OK]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 0
    [Connection Parameters in: 5674]
    CRC: 0x8d6029

Frame 6002: Packet, 26 bytes on wire (208 bits), 26 bytes captured (208 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6017
    Length of packet: 10
    Flags: 0x0b
        .... ...1 = CRC: Ok
        .... ..1. = Direction: Central -> Peripheral
        .... .0.. = Encrypted: No
        .... 1... = MIC (not relevant): 1
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 18
    RSSI: -51 dBm
    Event counter: 115
    Timestamp: 257536623µs
    [Packet time (start to end): 80µs]
    [Delta time (end to start): 48672µs]
    [Delta time (start to start): 48752µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..01 = LLID: Continuation fragment of an L2CAP message, or an Empty PDU (0x1)
        .... .0.. = Next Expected Sequence Number: 0 [ACK]
        .... 0... = Sequence Number: 0 [Retransmit]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 0
    [Connection Parameters in: 5674]
    CRC: 0x8d6029

Frame 6003: Packet, 201 bytes on wire (1608 bits), 201 bytes captured (1608 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6018
    Length of packet: 10
    Flags: 0x01
        .... ...1 = CRC: Ok
        .... ..0. = Direction: Peripheral -> Central
        .... .0.. = Encrypted: No
        .... 0... = MIC (not relevant): 0
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 18
    RSSI: -56 dBm
    Event counter: 115
    Timestamp: 257536853µs
    [Packet time (start to end): 1480µs]
    [Delta time (end to start): 150µs]
    [Delta time (start to start): 230µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..10 = LLID: Start of an L2CAP message or a complete L2CAP message with no fragmentation (0x2)
        .... .1.. = Next Expected Sequence Number: 1 [ACK]
        .... 0... = Sequence Number: 0 [OK]
        ...1 .... = More Data: True
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 175
    [L2CAP Index: 1572]
    [Connection Parameters in: 5674]
    CRC: 0x155f45
Bluetooth L2CAP Protocol
Bluetooth Attribute Protocol

Frame 6004: Packet, 26 bytes on wire (208 bits), 26 bytes captured (208 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6019
    Length of packet: 10
    Flags: 0x0b
        .... ...1 = CRC: Ok
        .... ..1. = Direction: Central -> Peripheral
        .... .0.. = Encrypted: No
        .... 1... = MIC (not relevant): 1
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 18
    RSSI: -52 dBm
    Event counter: 115
    Timestamp: 257538483µs
    [Packet time (start to end): 80µs]
    [Delta time (end to start): 150µs]
    [Delta time (start to start): 1630µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..01 = LLID: Continuation fragment of an L2CAP message, or an Empty PDU (0x1)
        .... .1.. = Next Expected Sequence Number: 1 [ACK]
        .... 1... = Sequence Number: 1 [OK]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 0
    [Connection Parameters in: 5674]
    CRC: 0x23b029

Frame 6005: Packet, 202 bytes on wire (1616 bits), 202 bytes captured (1616 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6020
    Length of packet: 10
    Flags: 0x01
        .... ...1 = CRC: Ok
        .... ..0. = Direction: Peripheral -> Central
        .... .0.. = Encrypted: No
        .... 0... = MIC (not relevant): 0
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 18
    RSSI: -56 dBm
    Event counter: 115
    Timestamp: 257538713µs
    [Packet time (start to end): 1488µs]
    [Delta time (end to start): 150µs]
    [Delta time (start to start): 230µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..10 = LLID: Start of an L2CAP message or a complete L2CAP message with no fragmentation (0x2)
        .... .0.. = Next Expected Sequence Number: 0 [ACK]
        .... 1... = Sequence Number: 1 [OK]
        ...1 .... = More Data: True
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 176
    [L2CAP Index: 1573]
    [Connection Parameters in: 5674]
    CRC: 0x4f0f29
Bluetooth L2CAP Protocol
Bluetooth Attribute Protocol

Frame 6006: Packet, 26 bytes on wire (208 bits), 26 bytes captured (208 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6021
    Length of packet: 10
    Flags: 0x0b
        .... ...1 = CRC: Ok
        .... ..1. = Direction: Central -> Peripheral
        .... .0.. = Encrypted: No
        .... 1... = MIC (not relevant): 1
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 18
    RSSI: -51 dBm
    Event counter: 115
    Timestamp: 257540351µs
    [Packet time (start to end): 80µs]
    [Delta time (end to start): 150µs]
    [Delta time (start to start): 1638µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..01 = LLID: Continuation fragment of an L2CAP message, or an Empty PDU (0x1)
        .... .0.. = Next Expected Sequence Number: 0 [ACK]
        .... 0... = Sequence Number: 0 [OK]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 0
    [Connection Parameters in: 5674]
    CRC: 0x8d6029

Frame 6007: Packet, 205 bytes on wire (1640 bits), 205 bytes captured (1640 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6022
    Length of packet: 10
    Flags: 0x01
        .... ...1 = CRC: Ok
        .... ..0. = Direction: Peripheral -> Central
        .... .0.. = Encrypted: No
        .... 0... = MIC (not relevant): 0
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 18
    RSSI: -55 dBm
    Event counter: 115
    Timestamp: 257540581µs
    [Packet time (start to end): 1512µs]
    [Delta time (end to start): 150µs]
    [Delta time (start to start): 230µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..10 = LLID: Start of an L2CAP message or a complete L2CAP message with no fragmentation (0x2)
        .... .1.. = Next Expected Sequence Number: 1 [ACK]
        .... 0... = Sequence Number: 0 [OK]
        ...1 .... = More Data: True
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 179
    [L2CAP Index: 1574]
    [Connection Parameters in: 5674]
    CRC: 0xe1579a
Bluetooth L2CAP Protocol
Bluetooth Attribute Protocol

Frame 6008: Packet, 26 bytes on wire (208 bits), 26 bytes captured (208 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6023
    Length of packet: 10
    Flags: 0x0b
        .... ...1 = CRC: Ok
        .... ..1. = Direction: Central -> Peripheral
        .... .0.. = Encrypted: No
        .... 1... = MIC (not relevant): 1
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 18
    RSSI: -56 dBm
    Event counter: 115
    Timestamp: 257542244µs
    [Packet time (start to end): 80µs]
    [Delta time (end to start): 151µs]
    [Delta time (start to start): 1663µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..01 = LLID: Continuation fragment of an L2CAP message, or an Empty PDU (0x1)
        .... .1.. = Next Expected Sequence Number: 1 [ACK]
        .... 1... = Sequence Number: 1 [OK]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 0
    [Connection Parameters in: 5674]
    CRC: 0x23b029

Frame 6009: Packet, 206 bytes on wire (1648 bits), 206 bytes captured (1648 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6024
    Length of packet: 10
    Flags: 0x01
        .... ...1 = CRC: Ok
        .... ..0. = Direction: Peripheral -> Central
        .... .0.. = Encrypted: No
        .... 0... = MIC (not relevant): 0
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 18
    RSSI: -55 dBm
    Event counter: 115
    Timestamp: 257542474µs
    [Packet time (start to end): 1520µs]
    [Delta time (end to start): 150µs]
    [Delta time (start to start): 230µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..10 = LLID: Start of an L2CAP message or a complete L2CAP message with no fragmentation (0x2)
        .... .0.. = Next Expected Sequence Number: 0 [ACK]
        .... 1... = Sequence Number: 1 [OK]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 180
    [L2CAP Index: 1575]
    [Connection Parameters in: 5674]
    CRC: 0x489e00
Bluetooth L2CAP Protocol
Bluetooth Attribute Protocol

Frame 6010: Packet, 26 bytes on wire (208 bits), 26 bytes captured (208 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6025
    Length of packet: 10
    Flags: 0x0b
        .... ...1 = CRC: Ok
        .... ..1. = Direction: Central -> Peripheral
        .... .0.. = Encrypted: No
        .... 1... = MIC (not relevant): 1
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 29
    RSSI: -57 dBm
    Event counter: 116
    Timestamp: 257585374µs
    [Packet time (start to end): 80µs]
    [Delta time (end to start): 41380µs]
    [Delta time (start to start): 42900µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..01 = LLID: Continuation fragment of an L2CAP message, or an Empty PDU (0x1)
        .... .0.. = Next Expected Sequence Number: 0 [ACK]
        .... 0... = Sequence Number: 0 [OK]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 0
    [Connection Parameters in: 5674]
    CRC: 0x8d6029

Frame 6011: Packet, 26 bytes on wire (208 bits), 26 bytes captured (208 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6026
    Length of packet: 10
    Flags: 0x0b
        .... ...1 = CRC: Ok
        .... ..1. = Direction: Central -> Peripheral
        .... .0.. = Encrypted: No
        .... 1... = MIC (not relevant): 1
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 3
    RSSI: -51 dBm
    Event counter: 117
    Timestamp: 257634125µs
    [Packet time (start to end): 80µs]
    [Delta time (end to start): 48671µs]
    [Delta time (start to start): 48751µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..01 = LLID: Continuation fragment of an L2CAP message, or an Empty PDU (0x1)
        .... .0.. = Next Expected Sequence Number: 0 [ACK]
        .... 0... = Sequence Number: 0 [Retransmit]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 0
    [Connection Parameters in: 5674]
    CRC: 0x8d6029

Frame 6012: Packet, 26 bytes on wire (208 bits), 26 bytes captured (208 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6027
    Length of packet: 10
    Flags: 0x0b
        .... ...1 = CRC: Ok
        .... ..1. = Direction: Central -> Peripheral
        .... .0.. = Encrypted: No
        .... 1... = MIC (not relevant): 1
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 14
    RSSI: -51 dBm
    Event counter: 118
    Timestamp: 257682877µs
    [Packet time (start to end): 80µs]
    [Delta time (end to start): 48672µs]
    [Delta time (start to start): 48752µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..01 = LLID: Continuation fragment of an L2CAP message, or an Empty PDU (0x1)
        .... .0.. = Next Expected Sequence Number: 0 [ACK]
        .... 0... = Sequence Number: 0 [Retransmit]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 0
    [Connection Parameters in: 5674]
    CRC: 0x8d6029

Frame 6013: Packet, 26 bytes on wire (208 bits), 26 bytes captured (208 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6028
    Length of packet: 10
    Flags: 0x0b
        .... ...1 = CRC: Ok
        .... ..1. = Direction: Central -> Peripheral
        .... .0.. = Encrypted: No
        .... 1... = MIC (not relevant): 1
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 25
    RSSI: -56 dBm
    Event counter: 119
    Timestamp: 257731628µs
    [Packet time (start to end): 80µs]
    [Delta time (end to start): 48671µs]
    [Delta time (start to start): 48751µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..01 = LLID: Continuation fragment of an L2CAP message, or an Empty PDU (0x1)
        .... .0.. = Next Expected Sequence Number: 0 [ACK]
        .... 0... = Sequence Number: 0 [Retransmit]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 0
    [Connection Parameters in: 5674]
    CRC: 0x8d6029

Frame 6014: Packet, 26 bytes on wire (208 bits), 26 bytes captured (208 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6029
    Length of packet: 10
    Flags: 0x0b
        .... ...1 = CRC: Ok
        .... ..1. = Direction: Central -> Peripheral
        .... .0.. = Encrypted: No
        .... 1... = MIC (not relevant): 1
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 36
    RSSI: -55 dBm
    Event counter: 120
    Timestamp: 257780379µs
    [Packet time (start to end): 80µs]
    [Delta time (end to start): 48671µs]
    [Delta time (start to start): 48751µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..01 = LLID: Continuation fragment of an L2CAP message, or an Empty PDU (0x1)
        .... .0.. = Next Expected Sequence Number: 0 [ACK]
        .... 0... = Sequence Number: 0 [Retransmit]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 0
    [Connection Parameters in: 5674]
    CRC: 0x8d6029

Frame 6015: Packet, 26 bytes on wire (208 bits), 26 bytes captured (208 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6030
    Length of packet: 10
    Flags: 0x0b
        .... ...1 = CRC: Ok
        .... ..1. = Direction: Central -> Peripheral
        .... .0.. = Encrypted: No
        .... 1... = MIC (not relevant): 1
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 10
    RSSI: -46 dBm
    Event counter: 121
    Timestamp: 257829130µs
    [Packet time (start to end): 80µs]
    [Delta time (end to start): 48671µs]
    [Delta time (start to start): 48751µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..01 = LLID: Continuation fragment of an L2CAP message, or an Empty PDU (0x1)
        .... .0.. = Next Expected Sequence Number: 0 [ACK]
        .... 0... = Sequence Number: 0 [Retransmit]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 0
    [Connection Parameters in: 5674]
    CRC: 0x8d6029

Frame 6016: Packet, 26 bytes on wire (208 bits), 26 bytes captured (208 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6031
    Length of packet: 10
    Flags: 0x0b
        .... ...1 = CRC: Ok
        .... ..1. = Direction: Central -> Peripheral
        .... .0.. = Encrypted: No
        .... 1... = MIC (not relevant): 1
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 21
    RSSI: -55 dBm
    Event counter: 122
    Timestamp: 257877882µs
    [Packet time (start to end): 80µs]
    [Delta time (end to start): 48672µs]
    [Delta time (start to start): 48752µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..01 = LLID: Continuation fragment of an L2CAP message, or an Empty PDU (0x1)
        .... .0.. = Next Expected Sequence Number: 0 [ACK]
        .... 0... = Sequence Number: 0 [Retransmit]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 0
    [Connection Parameters in: 5674]
    CRC: 0x8d6029

Frame 6017: Packet, 26 bytes on wire (208 bits), 26 bytes captured (208 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6032
    Length of packet: 10
    Flags: 0x0b
        .... ...1 = CRC: Ok
        .... ..1. = Direction: Central -> Peripheral
        .... .0.. = Encrypted: No
        .... 1... = MIC (not relevant): 1
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 32
    RSSI: -56 dBm
    Event counter: 123
    Timestamp: 257926633µs
    [Packet time (start to end): 80µs]
    [Delta time (end to start): 48671µs]
    [Delta time (start to start): 48751µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..01 = LLID: Continuation fragment of an L2CAP message, or an Empty PDU (0x1)
        .... .0.. = Next Expected Sequence Number: 0 [ACK]
        .... 0... = Sequence Number: 0 [Retransmit]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 0
    [Connection Parameters in: 5674]
    CRC: 0x8d6029

Frame 6018: Packet, 26 bytes on wire (208 bits), 26 bytes captured (208 bits) on interface COM10-4.6, id 0
nRF Sniffer for Bluetooth LE
    Board: 10
    Header Version: 3, Packet counter: 6033
    Length of packet: 10
    Flags: 0x0b
        .... ...1 = CRC: Ok
        .... ..1. = Direction: Central -> Peripheral
        .... .0.. = Encrypted: No
        .... 1... = MIC (not relevant): 1
        .000 .... = PHY: LE 1M (0)
        0... .... = Reserved: 0
    Channel Index: 8
    RSSI: -48 dBm
    Event counter: 124
    Timestamp: 257975384µs
    [Packet time (start to end): 80µs]
    [Delta time (end to start): 48671µs]
    [Delta time (start to start): 48751µs]
Bluetooth Low Energy Link Layer
    Access Address: 0x50654b9b
    [Central Address: RaspberryPi_20:0b:dd (88:a2:9e:20:0b:dd)]
    [Peripheral Address: MaximIntegra_ff:9e:b1 (00:18:80:ff:9e:b1)]
    Data Header
        .... ..01 = LLID: Continuation fragment of an L2CAP message, or an Empty PDU (0x1)
        .... .0.. = Next Expected Sequence Number: 0 [ACK]
        .... 0... = Sequence Number: 0 [Retransmit]
        ...0 .... = More Data: False
        ..0. .... = CTE Info: Not Present
        00.. .... = RFU: 0
        Length: 0
    [Connection Parameters in: 5674]
    CRC: 0x8d6029

[khpeterson]

Hacked the concept of overriding the host requested supervision timeout:

diff --git a/Libraries/Cordio/controller/sources/ble/lctr/lctr_main_conn_slave.c b/Libraries/Cordio/controller/sources/ble/lctr/lctr_main_conn_slave.c
index 79830502ee..8ae172dc75 100644
--- a/Libraries/Cordio/controller/sources/ble/lctr/lctr_main_conn_slave.c
+++ b/Libraries/Cordio/controller/sources/ble/lctr/lctr_main_conn_slave.c
@@ -247,6 +247,15 @@ void lctrSlvConnBuildOp(lctrConnCtx_t *pCtx)
   BbBleSlvConnEvent_t * const pConn = &pBle->op.slvConn;
   lctrConnInd_t * const pConnInd = &pLctrConnMsg->connEstablish.connInd;
 
+  uint16_t supTimeout = pConnInd->timeout;
+  if (supTimeout < 100) {
+      supTimeout = 100;
+      WsfTrace("lctrSlvConnBuildOp: overriding requested supervision timeout of %d with %d",
+               pConnInd->timeout, supTimeout);
+  }
+  WsfTrace("lctrSlvConnBuildOp: interval:%d, latency:%d, timeout:%d, txWinSize: %d",
+           pConnInd->interval, pConnInd->latency, supTimeout, pConnInd->txWinSize);
+
   memset(pOp, 0, sizeof(BbOpDesc_t));
   memset(pBle, 0, sizeof(BbBleData_t));
   memset(pConn, 0, sizeof(BbBleSlvConnEvent_t));
@@ -287,7 +296,7 @@ void lctrSlvConnBuildOp(lctrConnCtx_t *pCtx)
   /* pCtx->txHdr.nesn = 0; */               /* cleared in alloc */
   pCtx->data.slv.totalAcc = lctrCalcTotalAccuracy(pConnInd->masterSca);
   pCtx->maxLatency = pConnInd->latency;
-  pCtx->supTimeoutMs = LCTR_CONN_IND_TO_MS(pConnInd->timeout);
+  pCtx->supTimeoutMs = LCTR_CONN_IND_TO_MS(supTimeout);
   pCtx->authTimeoutMs = LL_DEF_AUTH_TO_MS;
   pCtx->pingPeriodMs = lctrCalcPingPeriodMs(pCtx, LL_DEF_AUTH_TO_MS);
   /* pCtx->llcpState = LCTR_LLCP_STATE_IDLE; */

And there was an improvement, though the issue persists:

khp@Kevins-MacBook-Pro-M1 % grep 'test complete' build/test-bluez-analog/repeats-20260122-02.log | wc -l
    1908
khp@Kevins-MacBook-Pro-M1 % grep 'test complete.*FAIL' build/test-bluez-analog/repeats-20260122-02.log | wc -l
      16

Here's another example of a log sequence of back-to-back RX errors this time spanning the expected 1s interval:

2026-01-22T19:06:22.591834: lctrSlvConnRxCompletion: BB failed with status=CRC_FAILED, handle=0, bleChan=2, eventCounter=172
2026-01-22T19:06:22.595081: Ble got evt 18
2026-01-22T19:06:22.689294: lctrSlvConnRxCompletion: BB failed with status=CRC_FAILED, handle=0, bleChan=14, eventCounter=174
2026-01-22T19:06:22.738093: lctrSlvConnRxCompletion: BB failed with status=CRC_FAILED, handle=0, bleChan=20, eventCounter=175
2026-01-22T19:06:22.761947: 04897000: tick
2026-01-22T19:06:22.835746: lctrSlvConnRxCompletion: BB failed with status=CRC_FAILED, handle=0, bleChan=32, eventCounter=177
2026-01-22T19:06:22.884325: lctrSlvConnRxCompletion: BB failed with status=CRC_FAILED, handle=0, bleChan=1, eventCounter=178
2026-01-22T19:06:22.933192: lctrSlvConnRxCompletion: BB failed with status=CRC_FAILED, handle=0, bleChan=7, eventCounter=179
2026-01-22T19:06:22.981832: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=13, eventCounter=180
2026-01-22T19:06:23.030879: lctrSlvConnRxCompletion: BB failed with status=CRC_FAILED, handle=0, bleChan=19, eventCounter=181
2026-01-22T19:06:23.079436: lctrSlvConnRxCompletion: BB failed with status=CRC_FAILED, handle=0, bleChan=25, eventCounter=182
2026-01-22T19:06:23.128220: lctrSlvConnRxCompletion: BB failed with status=CRC_FAILED, handle=0, bleChan=31, eventCounter=183
2026-01-22T19:06:23.176838: lctrSlvConnRxCompletion: BB failed with status=CRC_FAILED, handle=0, bleChan=0, eventCounter=184
2026-01-22T19:06:23.225659: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=6, eventCounter=185
2026-01-22T19:06:23.274720: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=12, eventCounter=186
2026-01-22T19:06:23.323806: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=18, eventCounter=187
2026-01-22T19:06:23.373199: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=24, eventCounter=188
2026-01-22T19:06:23.421482: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=30, eventCounter=189
2026-01-22T19:06:23.469449: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=36, eventCounter=190
2026-01-22T19:06:23.518310: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=5, eventCounter=191
2026-01-22T19:06:23.566943: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=11, eventCounter=192
2026-01-22T19:06:23.582564: Ble got evt 18
2026-01-22T19:06:23.615778: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=17, eventCounter=193
2026-01-22T19:06:23.664435: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=23, eventCounter=194
2026-01-22T19:06:23.713205: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=29, eventCounter=195
2026-01-22T19:06:23.761943: lctrSlvConnRxCompletion: BB failed with status=RX_TIMEOUT, handle=0, bleChan=35, eventCounter=196
2026-01-22T19:06:23.763302: 04898000: tick
2026-01-22T19:06:23.781240: lctrConnStatelessEventHandler: handle=0, state=2, event=SUP_TIMEOUT
2026-01-22T19:06:23.787441: lctrConnStatelessEventHandler: handle=0, state=3, event=TERMINATED

Without source for libphy it will be impossible for me to take this much further.

[khpeterson]

Trying to get to the bottom of this issue...

Setting the BlueZ ConnectionSupervisionTimeout to something other than the default is not a good option. And Tachyon/Qualcomm BlueZ with same timeout has no problem. Why?

As noted above the root cause appears to be long sequences of back-to-back Rx errors from the PHY combined with a relatively short timeout and long packet-to-packet interval.

Comparing the connection parameters requested by the RPi/Infineon and Particle Tachyon/Qualcomm BlueZ hosts:

RPi5/Infineon:

2026-01-01T12:16:03.088203: lctrSlvConnBuildOp: interval:39, latency:0, timeout:42, txWinSize: 42

Tachyon/Qualcomm:

2026-01-01T12:22:30.987353: lctrSlvConnBuildOp: interval:24, latency:0, timeout:42, txWinSize: 42

Wrt to back-to-back Rx errors, because the Tachyon packet-to-packet interval is short (24x1.25=30ms) compared to RPi5 (39x1.25=48.75ms), Tachyon can tolerate (42x10=420ms)/30ms=~14 back to back Rx errors before timing out whereas RPi5 can only tolerate (42x10=420ms)/48.75ms=~8 back to back RX errors.

To characterize this I ran a series of 200 x 20s connection repeats with firmware instrumented to capture back-to-back error histograms. The test setup looks like this:

Summary/Observations (details below):

1. At 9" there were no SUP_TIMEOUT events reported by the MAX32666FTHR for the Tachyon repeats; there were 11 for RPi5, slightly higher than 3% failure rate I reported earlier but still in line.
2. The # of SUP_TIMEOUT events for RPi5 corresponds exactly to the number of back-to-back Rx errors at the timeout threshold.
3. At 9', there were no SUP_TIMEOUT events reported for either host.
4. The number of Rx errors drops dramatically at 9' for Tachyon, but is still relatively high for RPi5.
5. Assuming the Nordic nRF52840 sniffer captures close to truth, the Wireshark traces confirm that RPi5 transmits 5-6 dB more power than Tachyon.

Bottom line: the MAX32666FTHR BLE receive path must be saturating at short distances resulting in high numbers of Rx errors. This is especially true with the RPi5 host which transmits 5-6 dB more power. And given the relatively high error rate for RPi at 9 feet, I suspect the RPi5/Infineon transmit path is saturating too.

Here are the error burst histograms, first for Tachyon/Qualcomm, timeout thresholds shown in red:

And then for RPi5/Infineon:

And for reference, here is the RSSI the sniffer sees for each host:

Same thing at 9 feet: