I cannot read a BLE characteristic on Bluetooth 5.0 but on Bluetooth 5.1 it work
Good day to all,
I'm having an issue with a BLE characteristic on the STM32WB55. I have a characteristic that is a read only (it doesn't notify or indicate), and currently, it is just a counter that increments every second. I'm running a P2Pserver, with 1 service and 3 characteristics.
When I read the characteristic with a client application on my desktop with BLE 5.1 it works (I also used my phone with BLE 5.1 and it also works).
When I try to read on my laptop with a BLE 5.0, it will only read the characteristic when the Bluetooth connects but after that doing a read doesn't work at all.
The only thing different is the Bluetooth version of my devices. Other than that I don't know what could be the cause.
If anyone has an idea on how to fix this issue please help, because I expect this simple application to be backward compatible to BLE 4.2.
I am using the most recent version of STM32cube and the most recent firmware package for my board.
Here is how I initialized the characteristic
/**
* P2P_State
*/
COPY_P2P_STATE_UUID(uuid16.Char_UUID_128);
ret = aci_gatt_add_char(aPeerToPeerContext.PeerToPeerSvcHdle,
UUID_TYPE_128, &uuid16,
0x02,
CHAR_PROP_READ,
ATTR_PERMISSION_NONE,
GATT_NOTIFY_READ_REQ_AND_WAIT_FOR_APPL_RESP,
0x10,
CHAR_VALUE_LEN_CONSTANT,
&(aPeerToPeerContext.P2PCommsStateHdle));
if (ret != BLE_STATUS_SUCCESS)
{
APP_DBG_MSG(" Fail : aci_gatt_add_char command : P2PCOMMSSTATE, error code: 0x%x \n\r", ret);
}
else
{
APP_DBG_MSG(" Success: aci_gatt_add_char command : P2PCOMMSSTATE \n\r");
}
The function P2PS_UpdateCounter() is called in main every 1 seconds.
and P2PS_STM_App_Update_Char(....), update the characteristics value. this function doesn't fail and finish succesffuly.
void P2PS_UpdateCounter( void )
{
static uint16_t ucMoreTimeCounter = 0;
ucMoreTimeCounter++;
if( P2P_Server_App_Context.Notification_Status )
{
P2PS_STM_App_Update_Char( P2P_STATE_CHAR_UUID, &ucMoreTimeCounter, 2 );
}
return;
}
tBleStatus P2PS_STM_App_Update_Char( uint16_t UUID, uint8_t *pPayload, uint16_t usLength )
{
tBleStatus result = BLE_STATUS_INVALID_PARAMS;
switch(UUID)
{
case P2P_STATE_CHAR_UUID:
result = aci_gatt_update_char_value(aPeerToPeerContext.PeerToPeerSvcHdle,
aPeerToPeerContext.P2PCommsStateHdle,
0, /* charValOffset */
usLength, /* charValueLen */
(uint8_t *) pPayload);
if (result != BLE_STATUS_SUCCESS)
{
APP_DBG_MSG(" Fail : aci_gatt_update_char_value STATE command, result : 0x%x \n\r", result);
// printf(" Fail : aci_gatt_update_char_value STATE command, result : 0x%x \n\r", result);
}
else
{
APP_DBG_MSG(" Success: aci_gatt_update_char_value STATE command\n\r");
// printf(" Success: aci_gatt_update_char_value STATE command\n\r");
}
break;
default:
break;
}
return result;
}/* end P2PS_STM_Init() */
And finally, In the function that handle ACI_GATT events below, on BLE5.1 when I do a read on the characteristic, I can see that the event ACI_GATT_READ_PERMIT_REQ_VSEVT_CODE every single time I do a read but on BLE 5.0, this event doesn't get triggered. it only triggered when a client connects.
static SVCCTL_EvtAckStatus_t PeerToPeer_Event_Handler(void *Event)
{
SVCCTL_EvtAckStatus_t return_value;
hci_event_pckt *event_pckt;
evt_blecore_aci *blecore_evt;
aci_gatt_attribute_modified_event_rp0 * attribute_modified;
aci_gatt_read_permit_req_event_rp0 *read_req;
aci_gatt_notification_complete_event_rp0 *notification_complete;
P2PS_STM_App_Notification_evt_t Notification;
return_value = SVCCTL_EvtNotAck;
event_pckt = (hci_event_pckt *)(((hci_uart_pckt*)Event)->data);
switch(event_pckt->evt)
{
case HCI_VENDOR_SPECIFIC_DEBUG_EVT_CODE:
{
blecore_evt = (evt_blecore_aci*)event_pckt->data;
switch(blecore_evt->ecode)
{
case ACI_GATT_ATTRIBUTE_MODIFIED_VSEVT_CODE:
{
............
}
break;
case ACI_GATT_READ_PERMIT_REQ_VSEVT_CODE :
/* USER CODE BEGIN EVT_BLUE_GATT_READ_PERMIT_REQ_BEGIN */
printf("BLE READ\n");
/* USER CODE END EVT_BLUE_GATT_READ_PERMIT_REQ_BEGIN */
read_req = (aci_gatt_read_permit_req_event_rp0*)blecore_evt->data;
if (read_req->Attribute_Handle == (aPeerToPeerContext.P2PCommsStateHdle + 1))
{
return_value = SVCCTL_EvtAckFlowEnable;
/*USER CODE BEGIN CUSTOM_STM_Service_1_Char_3_ACI_GATT_READ_PERMIT_REQ_VSEVT_CODE_1 */
/*USER CODE END CUSTOM_STM_Service_1_Char_3_ACI_GATT_READ_PERMIT_REQ_VSEVT_CODE_1*/
aci_gatt_allow_read(read_req->Connection_Handle);
/*USER CODE BEGIN CUSTOM_STM_Service_1_Char_3_ACI_GATT_READ_PERMIT_REQ_VSEVT_CODE_2 */
printf("BLE STATE\n");
/*USER CODE END CUSTOM_STM_Service_1_Char_3_ACI_GATT_READ_PERMIT_REQ_VSEVT_CODE_2*/
} /* if (read_req->Attribute_Handle == (aPeerToPeerContext.P2PCommsStateHdle + CHARACTERISTIC_VALUE_ATTRIBUTE_OFFSET))*/
/* USER CODE BEGIN EVT_BLUE_GATT_READ_PERMIT_REQ_END */
/* USER CODE END EVT_BLUE_GATT_READ_PERMIT_REQ_END */
break;
case ACI_GATT_NOTIFICATION_COMPLETE_VSEVT_CODE:
{
...............
break;
}
default:
break;
}
}
break; /* HCI_HCI_VENDOR_SPECIFIC_DEBUG_EVT_CODE_SPECIFIC */
default:
break;
}
return(return_value);
}/* end SVCCTL_EvtAckStatus_t */