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|
# Test MTU exchange (initiated by central) and the effect on notify and write
# size.
#
# See ble_mtu_peripheral.py which tests peripheral-initiated MTU exchange (not supported on btstack).
#
# Four connections are made:
#
# Test | Requested | Preferred | Result | Notes
# 0 | 300 (C) | 256 (P) | 256 |
# 1 | 300 (C) | 200 (P) | 200 |
# 2 | 300 (C) | 400 (P) | 300 |
# 3 | 300 (C) | 50 (P) | 50 | Shorter than 64 so the notification is truncated.
#
# For each connection a notification is sent by the server (peripheral) and a characteristic
# is written by the client (central) to ensure that the expected size is transmitted.
from micropython import const
import time, machine, bluetooth
TIMEOUT_MS = 5000
_IRQ_CENTRAL_CONNECT = const(1)
_IRQ_CENTRAL_DISCONNECT = const(2)
_IRQ_GATTS_WRITE = const(3)
_IRQ_PERIPHERAL_CONNECT = const(7)
_IRQ_PERIPHERAL_DISCONNECT = const(8)
_IRQ_GATTC_CHARACTERISTIC_RESULT = const(11)
_IRQ_GATTC_CHARACTERISTIC_DONE = const(12)
_IRQ_GATTC_WRITE_DONE = const(17)
_IRQ_GATTC_NOTIFY = const(18)
_IRQ_MTU_EXCHANGED = const(21)
SERVICE_UUID = bluetooth.UUID("A5A5A5A5-FFFF-9999-1111-5A5A5A5A5A5A")
CHAR_UUID = bluetooth.UUID("00000000-1111-2222-3333-444444444444")
CHAR = (
CHAR_UUID,
bluetooth.FLAG_READ | bluetooth.FLAG_WRITE | bluetooth.FLAG_NOTIFY,
)
SERVICE = (
SERVICE_UUID,
(CHAR,),
)
SERVICES = (SERVICE,)
waiting_events = {}
def irq(event, data):
if event == _IRQ_CENTRAL_CONNECT:
print("_IRQ_CENTRAL_CONNECT")
waiting_events[event] = data[0]
elif event == _IRQ_CENTRAL_DISCONNECT:
print("_IRQ_CENTRAL_DISCONNECT")
elif event == _IRQ_GATTS_WRITE:
print("_IRQ_GATTS_WRITE")
elif event == _IRQ_PERIPHERAL_CONNECT:
print("_IRQ_PERIPHERAL_CONNECT")
waiting_events[event] = data[0]
elif event == _IRQ_PERIPHERAL_DISCONNECT:
print("_IRQ_PERIPHERAL_DISCONNECT")
elif event == _IRQ_GATTC_CHARACTERISTIC_RESULT:
if data[-1] == CHAR_UUID:
print("_IRQ_GATTC_CHARACTERISTIC_RESULT", data[-1])
waiting_events[event] = data[2]
else:
return
elif event == _IRQ_GATTC_CHARACTERISTIC_DONE:
print("_IRQ_GATTC_CHARACTERISTIC_DONE")
elif event == _IRQ_GATTC_WRITE_DONE:
print("_IRQ_GATTC_WRITE_DONE")
elif event == _IRQ_GATTC_NOTIFY:
print("_IRQ_GATTC_NOTIFY", len(data[-1]), chr(data[-1][0]))
elif event == _IRQ_MTU_EXCHANGED:
print("_IRQ_MTU_EXCHANGED", data[-1])
waiting_events[event] = data[-1]
if event not in waiting_events:
waiting_events[event] = None
def wait_for_event(event, timeout_ms):
t0 = time.ticks_ms()
while time.ticks_diff(time.ticks_ms(), t0) < timeout_ms:
if event in waiting_events:
return waiting_events.pop(event)
machine.idle()
raise ValueError("Timeout waiting for {}".format(event))
# Acting in peripheral role.
def instance0():
multitest.globals(BDADDR=ble.config("mac"))
((char_handle,),) = ble.gatts_register_services(SERVICES)
ble.gatts_set_buffer(char_handle, 500, False)
multitest.next()
default_mtus = [256, 200, 400, 50]
try:
for i in range(4):
ble.config(mtu=default_mtus[i])
print("gap_advertise")
ble.gap_advertise(20_000, b"\x02\x01\x06\x04\xffMPY")
multitest.broadcast(f"peripheral:adv:{i}")
# Wait for central to connect to us.
conn_handle = wait_for_event(_IRQ_CENTRAL_CONNECT, TIMEOUT_MS)
# Inform the central that we have been connected to.
multitest.broadcast("peripheral is connected")
mtu = wait_for_event(_IRQ_MTU_EXCHANGED, TIMEOUT_MS)
multitest.wait(f"client:discovery:{i}")
print("gatts_notify")
ble.gatts_notify(conn_handle, char_handle, str(i) * 64)
wait_for_event(_IRQ_GATTS_WRITE, TIMEOUT_MS)
print("gatts_read")
data = ble.gatts_read(char_handle)
print("characteristic len:", len(data), chr(data[0]))
# Wait for the central to disconnect.
wait_for_event(_IRQ_CENTRAL_DISCONNECT, TIMEOUT_MS)
finally:
ble.active(0)
# Acting in central role.
def instance1():
multitest.next()
try:
for i in range(4):
ble.config(mtu=300)
multitest.wait(f"peripheral:adv:{i}")
print("gap_connect")
ble.gap_connect(BDADDR[0], BDADDR[1], TIMEOUT_MS)
conn_handle = wait_for_event(_IRQ_PERIPHERAL_CONNECT, TIMEOUT_MS)
# Wait for peripheral to be ready for MTU exchange.
# On ESP32 with NimBLE and IDF 5.4.2 (at least), if the MTU exchange occurs
# immediately after the peripheral connect event, the peripheral may see its
# _IRQ_MTU_EXCHANGED event before its _IRQ_CENTRAL_CONNECT event. The wait
# here ensures correct event ordering on the peripheral.
multitest.wait("peripheral is connected")
# Central-initiated mtu exchange.
print("gattc_exchange_mtu")
ble.gattc_exchange_mtu(conn_handle)
mtu = wait_for_event(_IRQ_MTU_EXCHANGED, TIMEOUT_MS)
print("gattc_discover_characteristics")
ble.gattc_discover_characteristics(conn_handle, 1, 65535)
value_handle = wait_for_event(_IRQ_GATTC_CHARACTERISTIC_RESULT, TIMEOUT_MS)
wait_for_event(_IRQ_GATTC_CHARACTERISTIC_DONE, TIMEOUT_MS)
multitest.broadcast(f"client:discovery:{i}")
wait_for_event(_IRQ_GATTC_NOTIFY, TIMEOUT_MS)
print("gattc_write")
ble.gattc_write(conn_handle, value_handle, chr(ord("a") + i) * (mtu - 3), 1)
wait_for_event(_IRQ_GATTC_WRITE_DONE, TIMEOUT_MS)
time.sleep_ms(300)
# Disconnect from peripheral.
print("gap_disconnect:", ble.gap_disconnect(conn_handle))
wait_for_event(_IRQ_PERIPHERAL_DISCONNECT, TIMEOUT_MS)
finally:
ble.active(0)
ble = bluetooth.BLE()
ble.active(1)
ble.irq(irq)
|
