6621CX系列芯片做主怎么使能从机notify

整体流程如下：
在发现服务的时候，记录从机服务相关句柄，在app_gattc_cmp_evt_handler里面做对应的操作（对从机的读写操作）

在app_gattc_sdp_svc_ind_handler()里面做如下操作：
for (uint8_t idx=0; idx<(ind->end_hdl - ind->start_hdl); idx++)
    {        // characteristic description
        if(ind->info[idx].att_type == GATTC_SDP_ATT_DESC)
        {            uint16_t char_hdl = ind->start_hdl + 1 + idx;            uint16_t uuid = ((ind->info[idx].att.uuid[1]<<8) | ind->info[idx].att.uuid[0]);
            LOG_DBG("desc:  0x%04x(%d), uuid: 0x%04x", char_hdl, char_hdl, uuid);            if (uuid == ATT_DESC_CLIENT_CHAR_CFG)
            {                //客户自己定义一个数据结构存储自己需要的东西,比如这里的notify的句柄
                app_env.central.connect[index].ccc_handle[app_env.central.connect[index].ccc_handle_num++] = char_hdl;
                LOG_DBG("CCC handle: 0x%02x(%d)", char_hdl, char_hdl);
            }
        }
    }

在app_gattc_cmp_evt_handler()里面做对应的操作，这里只以下发使能notify的操作为例
__STATIC int app_gattc_cmp_evt_handler(ke_msg_id_t const msgid,
                                       struct gattc_cmp_evt const *param,
                                       ke_task_id_t const dest_id,
                                       ke_task_id_t const src_id)
{
    LOG_VBS_FUNC();

    uint8_t conidx = KE_IDX_GET(src_id);
    uint8_t index = app_central_find_by_conidx(conidx);

    switch(param->operation)
    {
        case GATTC_READ:
            LOG_DBG("GATTC_READ");
            break;

        case GATTC_READ_LONG:
            LOG_DBG("GATTC_READ_LONG");
            break;

        case GATTC_READ_BY_UUID:
            LOG_DBG("GATTC_READ_BY_UUID");
            break;

        case GATTC_READ_MULTIPLE:
            LOG_DBG("GATTC_READ_MULTIPLE");
            break;

        case GATTC_WRITE:
            LOG_DBG("GATTC_WRITE");
            break;

        case GATTC_WRITE_NO_RESPONSE:
            LOG_DBG("GATTC_WRITE_NO_RESPONSE");
            break;

        case GATTC_SDP_DISC_SVC:
            LOG_DBG("GATTC_SDP_DISC_SVC");
            break;

        case GATTC_SDP_DISC_SVC_ALL:
        {
            LOG_DBG("GATTC_SDP_DISC_SVC_ALL");
            if (app_env.central.connect[index].ccc_handle_num != 0)
            {
                LOG_INF("Enable all notifications.");
                for (int i=0; i<app_env.central.connect[index].ccc_handle_num; i++)
                {
                    LOG_INF("CCC handle: 0x%02x(%d)", app_env.central.connect[index].ccc_handle[i],
                                                      app_env.central.connect[index].ccc_handle[i]);
                    prf_gatt_write_ntf_ind(&app_env.central.prf_env, conidx,
                                           app_env.central.connect[index].ccc_handle[i],
                                           PRF_CLI_START_NTF);
                }
            }
        } break;

        default:
            break;
    }
    return (KE_MSG_CONSUMED);
}