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I'm using CYW43012, which is controlled by another MCU through UART flow-control with standard HCI protocol (not Wiced).

Currently, I'm able to make it advertise normally. However, when I'm using a phone to connect to it, it always fail.

When I look into the HCI data, here is the result when phone is trying to connect to Cypress:


BLE_GAP_EVT_ADV_START --------------------------> Start advertising normally

hciEvtProcessMsg: evt=3E, data=0A00400001010FBA4B90174200000000000000000000000018000000480001

DM_CONN_OPEN_IND, r=0, cid=1 -------------------> Phone is trying to connect

hciEvtProcessMsg: evt=3E, data=14400000 --------> Channel selection Algorithm event

hciEvtProcessMsg: evt=FF, data=5500004000 ------> Vendor HCI event code 0x55, I don't know what the meaning of this event.

hciEvtProcessMsg: evt=05, data=00400008 --------> Disconnect event with reason 0x08 (Supervision timeout)

DM_CONN_CLOSE_IND, r=0, cid=1 ------------------> Connection close

hciEvtProcessMsg: evt=0E, data=01082000

hciEvtProcessCmdCmpl: 2008

hciEvtProcessMsg: evt=0E, data=01092000

hciEvtProcessCmdCmpl: 2009

hciEvtProcessMsg: evt=0E, data=01062000

hciEvtProcessCmdCmpl: 2006

hciEvtProcessMsg: evt=0E, data=010A2000

hciEvtProcessCmdCmpl: 200A

BLE_GAP_EVT_ADV_START --------------------------> Start advertising again


As you can see, when phone is trying to connect to Cypress, the Cypress sent back a vendor HCI event code 0x55 (marked as RED above).

I've tried finding on google if there is any document about this event code but no luck.

I doubt that this is the reason why the disconnection happens, as the MCU does not handle this event correctly, thus, there is no communication between host and the Cypress board, that leads to disconnect with supervision timeout.

Could you please help explain what is the meaning of this event and what steps do I need to make it connect successfully?

Thank you very much.

2 Replies
250 replies posted 100 solutions authored 100 replies posted


If you use WICED chips in Standard HCI mode, then it should behave totally as a standard Bluetooth Controller. In this mode, little Vendor HCI event should be seen because it is a standard Bluetooth Controller.

And from the log, I think the red line implies that the event code should be 0xFF while the event data is 5500004000?


Sincere regards from​ C. L.



Hi ChunleiL_51​,

Thank you very much for your response.

"The red line implies that the event code should be 0xFF while the event data is 5500004000?"

-> Yes, you are correct. The event code is 0xFF and the event data is 0x5500004000, sorry about the mistake.

And 0xFF, as far as I know, indicates that this is a Cypress vendor-specific event and I doubt that this is the reason why the disconnection happens.