how to change 'txid' after make a tp connection

[XXIN0]

Hi,

I want to change txid before send a daigrequest, but i did not see the function interface in isotp. Is there any good way to achieve this requirement?

import can
import isotp
import binascii
from udsoncan.connections import PythonIsoTpConnection

iso_tp_params = {
    "stmin": 0,
    "blocksize": 0,
    "wftmax": 0,
    "tx_data_length": 8,
    "tx_data_min_length": None,
    "tx_padding": 0xAA,
    "rx_flowcontrol_timeout": 1000,
    "rx_consecutive_frame_timeout": 1000,
    "max_frame_size": 4095,
    "can_fd": False,
    "bitrate_switch": True,
    # "rate_limit_window_size": 0.1,
}


def set_bus():
    return can.interface.Bus(
        interface="vector",
        channel='9',
        app_name="Python Can",
        bitrate=500000,
        fd=False,
        data_bitrate=2000000,
        tseg1_abr=63,
        tseg2_abr=16,
        sjw_abr=15,
        tseg1_dbr=15,
        tseg2_dbr=4,
        sjw_dbr=2,
        receive_own_messages=True)


can_bus = set_bus()
tp_address = isotp.Address(
    addressing_mode=isotp.AddressingMode.Normal_11bits,
    txid=0x701,
    rxid=0x709,
)

tp_stack = isotp.NotifierBasedCanStack(
    bus=can_bus, notifier=can.Notifier(can_bus, [can.Printer()]), address=tp_address, params=iso_tp_params
)
conn_tp = PythonIsoTpConnection(tp_stack)
if not conn_tp.is_open():
    conn_tp.open()

conn_tp.send(binascii.a2b_hex('1001'))  # send diag request with tx_id = 0x701

# how to change tx_id = 0x7df ,but do not make a new 'conn_tp' 

conn_tp.send(binascii.a2b_hex('1001'))  # send diag request with tx_id = 0x7df

[pylessard]

you can use the set_address() method on the stack object

https://can-isotp.readthedocs.io/en/latest/isotp/implementation.html#isotp.TransportLayer.set_address

[pylessard]

Carefull, set_address is not thread safe. you may want to take extra care when changing it.

if you only change the transmit part, I expect no issues. If you change the receiving address, you may mix can frames from different ECU

The safest way would be to stop, change the address, then start again

If that is not enough, we can consider adding thread safety around this method.