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上篇博文《Python调用周立功CAN接口卡接口库函数》仅做了发送数据例程,有网友在测试接收时出现了问题,在此给出自己的接收数据代码。
在此需要强调的是,因为经济水平有限,自己所使用的CAN接口卡为第三方兼容周立功函数库的接口卡,经测试,第三方CAN接口卡VCI_Receive接收函数其参数WaitTime是无效的,即使该值为-1,也不会阻塞等待数据,若使用周立功原版接口卡则无此问题。
以USBCAN-2E-U接口卡,1000k波特率,接收一帧数据并打印为例,代码如下:
import platform import time from ctypes import * class _VCI_INIT_CONFIG(Structure): _fields_ = [('AccCode', c_ulong), ('AccMask', c_ulong), ('Reserved', c_ulong), ('Filter', c_ubyte), ('Timing0', c_ubyte), ('Timing1', c_ubyte), ('Mode', c_ubyte)] class _VCI_CAN_OBJ(Structure): _fields_ = [('ID', c_uint), ('TimeStamp', c_uint), ('TimeFlag', c_byte), ('SendType', c_byte), ('RemoteFlag', c_byte), ('ExternFlag', c_byte), ('DataLen', c_byte), ('Data', c_byte*8), ('Reserved', c_byte*3)] vic = _VCI_INIT_CONFIG() vic.AccCode = 0x00000000 vic.AccMask = 0xffffffff vic.Filter = 0 vic.Timing0 = 0x00 vic.Timing1 = 0x1c vic.Mode = 0 vco = _VCI_CAN_OBJ() vco.ID = 0x00000001 vco.SendType = 0 vco.RemoteFlag = 0 vco.ExternFlag = 0 vco.DataLen = 8 vco.Data = (1, 2, 3, 4, 5, 6, 7, 8) canLib = windll.LoadLibrary('.\\CAN_Lib\\'+platform.architecture()[0]+'\\ControlCAN.dll') print('打开设备: %d' % (canLib.VCI_OpenDevice(21, 0, 0))) print('设置波特率: %d' % (canLib.VCI_SetReference(21, 0, 0, 0, pointer(c_int(0x060003))))) print('初始化: %d' % (canLib.VCI_InitCAN(21, 0, 0, pointer(vic)))) print('启动: %d' % (canLib.VCI_StartCAN(21, 0, 0))) print('清空缓冲区: %d' % (canLib.VCI_ClearBuffer(21, 0, 0))) while canLib.VCI_Receive(3, 0, 0, pointer(vco), 1, 50) == 0: pass else: for d in vco.Data: print(d)
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