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add BitTiming parameter to Usb2canBus
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zariiii9003 committed Jan 27, 2023
1 parent 7a4c6f8 commit 845f892
Showing 1 changed file with 37 additions and 7 deletions.
44 changes: 37 additions & 7 deletions can/interfaces/usb2can/usb2canInterface.py
Original file line number Diff line number Diff line change
Expand Up @@ -4,16 +4,24 @@

import logging
from ctypes import byref
from typing import Optional

from can import BusABC, Message, CanInitializationError, CanOperationError
from typing import Optional, Union

from can import (
BusABC,
Message,
CanInitializationError,
CanOperationError,
BitTiming,
BitTimingFd,
)
from .usb2canabstractionlayer import Usb2CanAbstractionLayer, CanalMsg, CanalError
from .usb2canabstractionlayer import (
IS_ERROR_FRAME,
IS_REMOTE_FRAME,
IS_ID_TYPE,
)
from .serial_selector import find_serial_devices
from ...util import check_or_adjust_timing_clock

# Set up logging
log = logging.getLogger("can.usb2can")
Expand Down Expand Up @@ -75,6 +83,13 @@ class Usb2canBus(BusABC):
Bitrate of channel in bit/s. Values will be limited to a maximum of 1000 Kb/s.
Default is 500 Kbs
:param timing:
Optional :class:`~can.BitTiming` instance to use for custom bit timing setting.
If this argument is set then it overrides the bitrate argument. The
`f_clock` value of the timing instance must be set to 32_000_000 (32MHz)
for standard CAN.
CAN FD and the :class:`~can.BitTimingFd` class are not supported.
:param flags:
Flags to directly pass to open function of the usb2can abstraction layer.
Expand All @@ -96,6 +111,7 @@ def __init__(
flags: int = 0x00000008,
*_,
bitrate: int = 500000,
timing: Optional[Union[BitTiming, BitTimingFd]] = None,
serial: Optional[str] = None,
**kwargs,
):
Expand All @@ -112,12 +128,26 @@ def __init__(
raise CanInitializationError("could not automatically find any device")
device_id = devices[0]

# convert to kb/s and cap: max rate is 1000 kb/s
baudrate = min(int(bitrate // 1000), 1000)

self.channel_info = f"USB2CAN device {device_id}"

connector = f"{device_id}; {baudrate}"
if isinstance(timing, BitTiming):
timing = check_or_adjust_timing_clock(timing, valid_clocks=[32_000_000])
connector = (
f"{device_id};"
"0;"
f"{timing.tseg1};"
f"{timing.tseg2};"
f"{timing.sjw};"
f"{timing.brp}"
)
elif isinstance(timing, BitTimingFd):
raise NotImplementedError(
f"CAN FD is not supported by {self.__class__.__name__}."
)
else:
# convert to kb/s and cap: max rate is 1000 kb/s
baudrate = min(int(bitrate // 1000), 1000)
connector = f"{device_id};{baudrate}"
self.handle = self.can.open(connector, flags)

super().__init__(channel=channel, **kwargs)
Expand Down

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