Code.py found on "Adafruit CircuitPython 6.2.0 on 2021-04-05; Adafruit ItsyBitsy nRF52840 Express with nRF52840" date 2020/04/14

Dual_mouse_bug.py

###
# Dual BLE mouse jiggling:
#  Advertise a first mouse as "CircuitPython HID1"
#  Once we have a first connection
#  Advertise a second mouse as "CircuitPython HID2"
#
# Once the first mouse is connected the jiggling start.
# Mouse1 should do Left-Right movement
# Mouse2 (once connected) should do Up-Down movement
#
# BUG?: Mouse2 does square move, so it gets the move for Mouse1.
###

import adafruit_ble

from adafruit_ble.advertising import Advertisement
from adafruit_ble.advertising.standard import ProvideServicesAdvertisement
from adafruit_ble.services.standard.hid import HIDService
from adafruit_ble.services.standard.device_info import DeviceInfoService
from adafruit_hid.mouse import Mouse

import time
import board

hid1 = HIDService()
device_info = DeviceInfoService(software_revision=adafruit_ble.__version__, manufacturer="Adafruit Industries")
advertisement1 = ProvideServicesAdvertisement(hid1)
advertisement1.appearance = 961
scan_response1 = Advertisement()
scan_response1.complete_name = "CircuitPython HID1"

ble = adafruit_ble.BLERadio()

if not ble.connected:
    print("advertising1")
    ble.start_advertising(advertisement1, scan_response1)
else:
    print("already connected")
    print(ble.connections)

# This is a BLE mouse
mouse1 = Mouse(hid1.devices)

hid2 = HIDService()
advertisement2 = ProvideServicesAdvertisement(hid2)
advertisement2.appearance = 961
scan_response2 = Advertisement()
scan_response2.complete_name = "CircuitPython HID2"

# If I do the following before I get a connection on the first advertisement...
#   ble.start_advertising(advertisement2, scan_response2)
# It produce the following error...
#   _bleio.BluetoothError: Already advertising.

# This is a trick to wait for a first connection before making a new advertisement
while len(ble.connections) < 1:
    pass

print("advertising2")
ble.start_advertising(advertisement2, scan_response2)

# This is a BLE mouse
mouse2 = Mouse(hid2.devices)

m=10
s=1

# This works even if mouse2 is not connected yet
while True:
    while not ble.connected:
        pass
    print("Start shaking the mouse for you.")

    while ble.connected:
        time.sleep(s);        mouse1.move(x=m);
        time.sleep(s);                              mouse2.move(y=m);
        time.sleep(s);        mouse1.move(x=-m);
        time.sleep(s);                              mouse2.move(y=-m);

# This is far from perfect, we only advertise 1 where the second is not there too.
    ble.start_advertising(advertisement1)