We're trying to build an HF audio gateway using CYW920706WCDEVAL and unmodified example software provided with WICED Studio 6.4 (WICED-SDK Version: Wiced_006.004.000.0061 / b38d42ee8368ff374b13514286120afd9e788a07), and we have troubles connecting AirPods to the evaluation board, and I think the WeSCO setting can be the reason for those. Comparing air traces for a mobile phone and CYW20706 I could see that "LMP eSCO Link Request" by the mobile phone is accepted by AirPods, while the request from our product is not answered at all. The only difference between those 2 requests is WeSCO - mobile phone sets it to 4, while CYBT sets it to 6.
When CYW920706 requests an eSCO link towards a headset (see code snippet below), it results in "LMP eSCO Link Request" for 2-EV3 packets where WeSCO parameter in is set to 6 slots. However, according to Bluetooth Core specs (Link Manager Protocol Specification, Table 5.3: Mandatory parameter ranges for eSCO packet types) this parameter for 2-EV3 packets shall be 0, 2 or 4.
Please advise, how to force WeSCO become 4 instead of 6.
wiced_bt_sco_params_t params;
params.use_wbs = WICED_TRUE;
params.max_latency = 13;
params.retrans_effort = BTM_ESCO_RETRANS_QUALITY;
params.packet_types = ( BTM_SCO_PKT_TYPES_MASK_EV3 | /* EV3 + 2-EV3 */
BTM_SCO_PKT_TYPES_MASK_NO_3_EV3 |
BTM_SCO_PKT_TYPES_MASK_NO_2_EV5 |
BTM_SCO_PKT_TYPES_MASK_NO_3_EV5 );
status = wiced_bt_sco_create_as_initiator(p_scb->hf_addr, &p_scb->sco_idx, ¶ms);
