Bluetooth WiPy client connecting to WiPy peripheral

[lcgeldenhuys]

Hi,

I have a WiPy setup as a BLE peripheral as per the example:

import binascii
from network import Bluetooth
from machine import Timer

bt_periph = Bluetooth()
bt_periph.set_advertisement(name = 'mag_test', service_uuid = b'1234567890123456')

def conn_cb (bt_o):
    events = bt_o.events()
    if  events & Bluetooth.CLIENT_CONNECTED:
        bt_o.advertise(False)
        print("Client connected")
    elif events & Bluetooth.CLIENT_DISCONNECTED:
        bt_o.advertise(True)
        print("Client disconnected")

bt_periph.callback(trigger = Bluetooth.CLIENT_CONNECTED | Bluetooth.CLIENT_DISCONNECTED, handler = conn_cb)
bt_periph.advertise(True)
srv_test = bt_periph.service(uuid = b'1234567890123456', isprimary = True, nbr_chars = 1)
blaster = srv_test.characteristic(uuid = b'ab34567890123456', properties = Bluetooth.PROP_READ, value = 55)

def blaster_cb(chr):
    print("Read request, returning value = {}".format(blaster.value()))

blaster_cb = blaster.callback(trigger = Bluetooth.CHAR_READ_EVENT, handler = blaster_cb)

I also have a WiPy setup as a client, trying to connect so I can read the service characteristic. However, whilst the peripheral is telling me that the client is connected, the client tells me that it is not:

import binascii
from network import Bluetooth
import time

bt_client = Bluetooth()
bt_client.start_scan(-1)

while True:
	adv = bt_client.get_adv()
	if adv and bt_client.resolve_adv_data(adv.data, Bluetooth.ADV_NAME_CMPL) == 'mag_test':
		print ("Found mag test peripheral")
		print("RSSI : {}, MAC : {}".format(adv.rssi, binascii.hexlify(adv.mac)))
		bt_client.stop_scan()
		
		try:
			conn = bt_client.connect(adv.mac)
			while not conn.isconnected():
				conn = bt_client.connect(adv.mac)
				time.sleep(0.100)

			print("Connected...")

			services = conn.services()
		    
			for service in services:
				time.sleep(0.300)
				if type(service.uuid()) == bytes:
					print('Reading characteristics from service = {}'.format(service.uuid()))
				else:
					print('Reading characteristics from service = %x' % service.uuid())
		      	
				chars = service.characteristics()
		      	
				while conn.isconnected():
					for idx, char in enumerate(chars):
						if (char.properties() & Bluetooth.PROP_READ):
							print("char.read : {}".format(char.read()))
						time.sleep(1.000)
		   	
			print("Disconnected...")
			break
		
		except Exception as ex:
			print("Exception caught...")
			print(ex)
	
	else:
		time.sleep(0.050)

The conn.isconnected() never returns True, despite the peripheral reporting a connection. I know the connection works, because I can connect and read the characteristic value with a smartphone application.

If I ignore the False connection state and try to create a services object anyway services = conn.services() then an exception is generated with "connection is already closed"

Any help for troubleshooting / hunting down the cause would be greatly appreciated.

Lourens

[daniel]

Hello,

Thanks for pointing out this bug. It has been fixed on the latest release 1.7.1.b1.

Cheers,
Daniel

[yunying]

I have the same problem with two Lopy, I lose connection immediately:)

[jmarcelino]

@Innocenzo
That's OK. As we all know there is no magic, only great science and engineering. ;-)

Seriously now, we all get that message it's related to storage of BLE bonding keys in the NVS ( non-volatile storage ) area which isn't ready yet. Nothing to worry about.

[Innocenzo]

When power up the BLE I Have this messages:

BTDM CONTROLLER VERSION: 010101
BTDM ROM VERSION 0101
BD_ADDR: 24:0A:C4:XX:XX:XX
NVDS MAGIC FAILED
RF Init OK with coex
Enable Classic BT
Enable Low Energy

[Innocenzo]

@jmarcelino I try also to increase the sleep time (a connection every 2 seconds) but the problem persists

[jmarcelino]

I understand you're re-trying to connect but triggering a new connection ( conn = bt_client.connect() ) ten times a second sounds like a bad idea to me. I can't see why you'd have to do that but I'll do some tests later today.

[Innocenzo]

@lcgeldenhuys So the problem is the WiPy firmware? I actually use the release 1.6.7.b1 and your code does not work.

There is a fix for that or the only way to perform a BLE connection is to downgrade the firmware?

[lcgeldenhuys]

I downgraded to 1.4.0.b1 as I was sure this worked some time ago, and indeed, it works again!

[lcgeldenhuys]

Also, tried using the example client code to connect to other peripherals, e.g. the Tile. Same behaviour, namely a mobile app (specifically https://itunes.apple.com/us/app/lightblue-explorer-bluetooth/id557428110?mt=8) is able to connect and interrogate the services and characteristics, but the WiPy fails.

Using current firmware 1.6.5.b1