python-can使用总结
python-can的使用总结
简介
python-can库为Python提供了控制器局域网的支持，为不同的硬件设备提供了通用的抽象，并提供了一套实用程序，用于在CAN总线上发送和接收消息。
支持的硬件接口：
| Name | Documentation |
|---|---|
| “socketcan” | SocketCAN |
| “kvaser” | Kvaser’s CANLIB |
| “serial” | CAN over Serial |
| “slcan” | CAN over Serial / SLCAN |
| “ixxat” | IXXAT Virtual CAN Interface |
| “pcan” | PCAN Basic API |
| “usb2can” | USB2CAN Interface |
| “nican” | NI-CAN |
| “iscan” | isCAN |
| “neovi” | NEOVI Interface |
| “vector” | Vector |
| “virtual” | Virtual |
| “canalystii” | CANalyst-II |
| “systec” | SYSTEC interface |
使用
1、首先导入库
import can
2、实例化Canalyst, PeakCAN
def SetChannel():
global bus_instance
print("实例化pcan")
bus_instance = can.interface.Bus(bustype='pcan', channel='PCAN_USBBUS1',bitrate=500000)
def SetChannel_can(ChannelNumber):
global bus_instance
print("实例化can")
print(ChannelNumber)
bus_instance = can.interface.Bus(bustype='canalystii', channel=ChannelNumber, bitrate=500000)
3、发送报文
def SendMessage(canMessage):
bus_instance.send(canMessage, 0.1)
can_data_list = [0, 0, 0, 0, 0, 0, 0, 0]
can_message = can.Message(arbitration_id=SendID, data=can_data_list, is_extended_id=False)
SendMessage(can_message)
can.message(timestamp=0.0, //时间戳
arbitration_id=0, //报文id
is_extended_id=True, //是否为扩展帧
is_remote_frame=False, //是否为远程帧
is_error_frame=False, //是否为错误帧
channel=None, //通道
dlc=None, //dlc大小
data=None, //数据
is_fd=False, //是否为canfd
is_rx=True, //是否为接收帧
bitrate_switch=False, //比特率开关
error_state_indicator=False,
check=False)
4、接收报文（rcvId换成自己的报文id，如0x123）
def recv_message(rcvId):
recv_id = 0x123
can_filter = [{"can_id": recv_id, "can_mask": 0xFFFFFFFF}]
bus_instance.set_filters(can_filter)
# state = bus_instance.status()
# print("pcan总线状态：", state)
message = bus_instance.recv(0.001)
return message
报文数据在message的data中
message = recv_message(RcvID)
recv_can_data = message.data
# recv_can_data[0]...
另一种处理数据的方法
message = recv_message(RcvID)
recv_can_msg = str(message).split()
can_id = recv_can_msg[3] # eg:'00000123',注意id的格式
can_data0 = recv_can_msg[7] # eg:'ff'
can_data1 = recv_can_msg[8]
can_data2 = recv_can_msg[9]
can_data3 = recv_can_msg[10]
can_data4 = recv_can_msg[11]
can_data5 = recv_can_msg[12]
can_data6 = recv_can_msg[13]
can_data7 = recv_can_msg[14]
can_data0 = int(can_data0,16) # eg:255即0xff
5、清空缓存区
# 丢弃可能在输出缓冲区排队的每一条信息
def resetTxBuffer():
bus_instance.flush_tx_buffer()
6、pcan清空缓存区接收到的报文不对的话要重置总线
# 重置总线
def resetBus():
bus_instance.reset()
7、pcan切换芯片后再次实例化报错初始化失败时需要关闭总线
# 关闭总线
def shutdownBus():
bus_instance.shutdown()