BlueNRG: Not notified when attribute is written

[occam25]

I have modified the BlueNRG sensor demo adding a new characteristic to turn on/off a LED. I want to be notified when the client (the smartphone) sends data so I can check the written value to change the LED status accordinly.

I have tried many options but I am not being notified for writes, only for reads.

This is the characteristic added (just bellow de humidity characteristic):

COPY_LED_CHAR_UUID(uuid);
 ret =  aci_gatt_add_char(envSensServHandle, 
    	 UUID_TYPE_128, 
    	uuid, 
 	2,
 	CHAR_PROP_WRITE | CHAR_PROP_WRITE_WITHOUT_RESP,
	ATTR_PERMISSION_NONE, 
    	GATT_NOTIFY_WRITE_REQ_AND_WAIT_FOR_APPL_RESP | GATT_NOTIFY_ATTRIBUTE_WRITE,
 	16, 
    	0, 
   	&ledCharHandle);
    if (ret != BLE_STATUS_SUCCESS) goto fail;
 
    charFormat.format = FORMAT_UINT16;
    charFormat.exp = -1;
    charFormat.unit = UNIT_UNITLESS;
    charFormat.name_space = 0;
    charFormat.desc = 0;
 
    uuid16 = CHAR_FORMAT_DESC_UUID;
 
    ret = aci_gatt_add_char_desc(envSensServHandle,
    				 ledCharHandle,
                                 UUID_TYPE_16,
                                 (uint8_t *)&uuid16,
                                 7,
                                 7,
                                 (void *)&charFormat,
                                 ATTR_PERMISSION_NONE,
				 ATTR_PERMISSION_NONE, 
				 ATTR_ACCESS_WRITE_REQ_ONLY, 
                                 16,
                                 FALSE,
                                 &descHandle);
    if (ret != BLE_STATUS_SUCCESS) goto fail;

The return value is BLE_STATUS_SUCCESS

Then, in the user_notify callback, I add the EVT_BLUE_GATT_WRITE_PERMIT_REQ event but it is never called.

  case EVT_VENDOR:
	{
		evt_blue_aci *blue_evt = (void*)event_pckt->data;
		switch(blue_evt->ecode){
		case EVT_BLUE_GATT_READ_PERMIT_REQ:
		{
			evt_gatt_read_permit_req *pr = (void*)blue_evt->data;
			Read_Request_CB(pr->attr_handle);
			break;
		}
		// ADDED THE WRITE REQUEST NOTIFICATION
		case EVT_BLUE_GATT_WRITE_PERMIT_REQ:
		{
			evt_gatt_write_permit_req *pr = (void *)blue_evt->data;
			Write_Request_CB(pr);
			break;
		}
		}
	}

Am I missing something? do I need to do anything else in order to get the write notifications? (read notifications work perfectly)

I have been stuck with this for a long time, any help will be appreciated!

Thanks

[occam25 · Accepted solution]

Just in case it is useful to someone, It turned out that the code is ok and the problem was in the smartphone app. In app inventor. I was using the writeBytes call but it doesn't work properly. After changing to writeStrings the write notification worked like a charm

[Avan .12]

Excellent! Thank you!