使用python来调用CAN通讯的DLL实现方法

Python  /  管理员 发布于 7年前   237

由于工作上的需要，经常要与USBCAN打交道，但厂家一般不会提供PYTHON的例子，于是自己摸索地写一个例子出来，以便在工作上随时可以使用PYTHON来测试CAN的功能。这里的例子是使用珠海创芯科技有限公司的USBCAN接口卡，他们提供一个ControlCAN.dll，也提供了一个.h文件，如下：

#ifndef CONTROLCAN_H#define CONTROLCAN_H ////文件版本：v2.00 20150920//#include <cvidef.h>//使用CVI平台开发，请使用该语句。 //接口卡类型定义 #define VCI_USBCAN13#define VCI_USBCAN24#define VCI_USBCAN2A4 #define VCI_USBCAN_E_U 20#define VCI_USBCAN_2E_U 21   //函数调用返回状态值#defineSTATUS_OK1#define STATUS_ERR0/*------------------------------------------------兼容ZLG的函数及数据类型------------------------------------------------*///1.ZLGCAN系列接口卡信息的数据类型。typedef struct _VCI_BOARD_INFO{unsigned shorthw_Version;unsigned shortfw_Version;unsigned shortdr_Version;unsigned shortin_Version;unsigned shortirq_Num;unsigned charcan_Num;charstr_Serial_Num[20];charstr_hw_Type[40];unsigned shortReserved[4];} VCI_BOARD_INFO,*PVCI_BOARD_INFO;  //2.定义CAN信息帧的数据类型。typedef struct _VCI_CAN_OBJ{unsigned intID;unsigned intTimeStamp;unsigned charTimeFlag;unsigned charSendType;unsigned charRemoteFlag;//是否是远程帧unsigned charExternFlag;//是否是扩展帧unsigned charDataLen;unsigned charData[8];unsigned charReserved[3];}VCI_CAN_OBJ,*PVCI_CAN_OBJ; //3.定义初始化CAN的数据类型typedef struct _VCI_INIT_CONFIG{unsigned longAccCode;unsigned longAccMask;unsigned longReserved;unsigned charFilter;unsigned charTiming0;unsigned charTiming1;unsigned charMode;}VCI_INIT_CONFIG,*PVCI_INIT_CONFIG; ///////// new add struct for filter /////////typedef struct _VCI_FILTER_RECORD{unsigned longExtFrame;//是否为扩展帧unsigned longStart;unsigned longEnd;}VCI_FILTER_RECORD,*PVCI_FILTER_RECORD; #define EXTERNCextern "C" EXTERNC unsigned long __stdcall VCI_OpenDevice(unsigned long DeviceType,unsigned long DeviceInd,unsigned long Reserved);EXTERNC unsigned long __stdcall VCI_CloseDevice(unsigned long DeviceType,unsigned long DeviceInd);EXTERNC unsigned long __stdcall VCI_InitCAN(unsigned long DeviceType, unsigned long DeviceInd, unsigned long CANInd, PVCI_INIT_CONFIG pInitConfig); EXTERNC unsigned long __stdcall VCI_ReadBoardInfo(unsigned long DeviceType,unsigned long DeviceInd,PVCI_BOARD_INFO pInfo); EXTERNC unsigned long __stdcall VCI_SetReference(unsigned long DeviceType,unsigned long DeviceInd,unsigned long CANInd,unsigned long RefType,void* pData); EXTERNC unsigned long __stdcall VCI_GetReceiveNum(unsigned long DeviceType,unsigned long DeviceInd,unsigned long CANInd);EXTERNC unsigned long __stdcall VCI_ClearBuffer(unsigned long DeviceType,unsigned long DeviceInd,unsigned long CANInd); EXTERNC unsigned long __stdcall VCI_StartCAN(unsigned long DeviceType,unsigned long DeviceInd,unsigned long CANInd);EXTERNC unsigned long __stdcall VCI_ResetCAN(unsigned long DeviceType,unsigned long DeviceInd,unsigned long CANInd); EXTERNC unsigned long __stdcall VCI_Transmit(unsigned long DeviceType,unsigned long DeviceInd,unsigned long CANInd,PVCI_CAN_OBJ pSend,unsigned long Len);EXTERNC unsigned long __stdcall VCI_Receive(unsigned long DeviceType,unsigned long DeviceInd,unsigned long CANInd,PVCI_CAN_OBJ pReceive,unsigned long Len,int WaitTime);  /*------------------------------------------------其他补充函数及数据结构描述------------------------------------------------*/ //USB-CAN总线适配器板卡信息的数据类型1，该类型为VCI_FindUsbDevice函数的返回参数。typedef struct _VCI_BOARD_INFO1{unsigned longhw_Version;unsigned longfw_Version;unsigned longdr_Version;unsigned longin_Version;unsigned longirq_Num;unsigned charcan_Num;unsigned charReserved;charstr_Serial_Num[8];charstr_hw_Type[16];charstr_Usb_Serial[4][4];} VCI_BOARD_INFO1,*PVCI_BOARD_INFO1; //USB-CAN总线适配器板卡信息的数据类型2，该类型为VCI_FindUsbDevice函数的返回参数。为扩展更多的设备typedef struct _VCI_BOARD_INFO2{unsigned longhw_Version;unsigned longfw_Version;unsigned longdr_Version;unsigned longin_Version;unsigned longirq_Num;unsigned charcan_Num;unsigned charReserved;charstr_Serial_Num[8];charstr_hw_Type[16];charstr_Usb_Serial[10][4];} VCI_BOARD_INFO2,*PVCI_BOARD_INFO2;  #define EXTERNCextern "C" EXTERNC unsigned long __stdcall VCI_GetReference2(unsigned long DevType,unsigned long DevIndex,unsigned long CANIndex,unsigned long Reserved,unsigned char *pData);EXTERNC unsigned long __stdcall VCI_SetReference2(unsigned long DevType,unsigned long DevIndex,unsigned long CANIndex,unsigned long RefType,unsigned char *pData);  EXTERNC unsigned long __stdcall VCI_ConnectDevice(unsigned long DevType,unsigned long DevIndex);EXTERNC unsigned long __stdcall VCI_UsbDeviceReset(unsigned long DevType,unsigned long DevIndex,unsigned long Reserved);EXTERNC unsigned long __stdcall VCI_FindUsbDevice(PVCI_BOARD_INFO1 pInfo);EXTERNC unsigned long __stdcall VCI_FindUsbDevice2(PVCI_BOARD_INFO2 pInfo);   #endif 

要调用这些函数才可以完成工作，下面就来创建一个例子，从CAN的通道0向通道1来发送一帧CAN数据，例子代码如下：

#python3.6 32位#https://blog.csdn.net/caimouse/article/details/51749579#开发人员：蔡军生（QQ：9073204） 深圳 2018-3-25#from ctypes import * VCI_USBCAN2A = 4STATUS_OK = 1class 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_ubyte),        ("SendType", c_ubyte),        ("RemoteFlag", c_ubyte),        ("ExternFlag", c_ubyte),        ("DataLen", c_ubyte),        ("Data", c_ubyte*8),        ("Reserved", c_ubyte*3)        ]  CanDLLName = 'ControlCAN.dll' #DLL是32位的，必须使用32位的PYTHONcanDLL = windll.LoadLibrary(CanDLLName)print(CanDLLName) ret = canDLL.VCI_OpenDevice(VCI_USBCAN2A, 0, 0)print(ret)if ret != STATUS_OK:  print('调用 VCI_OpenDevice出错\r\n') #初始0通道vci_initconfig = VCI_INIT_CONFIG(0x80000008, 0xFFFFFFFF, 0,     2, 0x00, 0x1C, 0)ret = canDLL.VCI_InitCAN(VCI_USBCAN2A, 0, 0, byref(vci_initconfig))if ret != STATUS_OK:  print('调用 VCI_InitCAN出错\r\n') ret = canDLL.VCI_StartCAN(VCI_USBCAN2A, 0, 0)if ret != STATUS_OK:  print('调用 VCI_StartCAN出错\r\n') #初始1通道ret = canDLL.VCI_InitCAN(VCI_USBCAN2A, 0, 1, byref(vci_initconfig))if ret != STATUS_OK:  print('调用 VCI_InitCAN 1 出错\r\n') ret = canDLL.VCI_StartCAN(VCI_USBCAN2A, 0, 1)if ret != STATUS_OK:  print('调用 VCI_StartCAN 1 出错\r\n') #通道0发送数据ubyte_array = c_ubyte*8a = ubyte_array(1,2,3,4, 5, 6, 7, 64)ubyte_3array = c_ubyte*3b = ubyte_3array(0, 0 , 0)vci_can_obj = VCI_CAN_OBJ(0x0, 0, 0, 1, 0, 0, 8, a, b) ret = canDLL.VCI_Transmit(VCI_USBCAN2A, 0, 0, byref(vci_can_obj), 1)if ret != STATUS_OK:  print('调用 VCI_Transmit 出错\r\n') #通道1接收数据a = ubyte_array(0, 0, 0, 0, 0, 0, 0, 0)vci_can_obj = VCI_CAN_OBJ(0x0, 0, 0, 1, 0, 0, 8, a, b)ret = canDLL.VCI_Receive(VCI_USBCAN2A, 0, 1, byref(vci_can_obj), 1, 0)print(ret)while ret <= 0:  print('调用 VCI_Receive 出错\r\n')  ret = canDLL.VCI_Receive(VCI_USBCAN2A, 0, 1, byref(vci_can_obj), 1, 0)if ret > 0:  print(vci_can_obj.DataLen)  print(list(vci_can_obj.Data)) #关闭canDLL.VCI_CloseDevice(VCI_USBCAN2A, 0) 

运行结果输出如下：

ControlCAN.dll
1
1
8

[1, 2, 3, 4, 5, 6, 7, 64]

可以看到从通道1里收通道0发过来的数据，达到这个程序的目的。

以上这篇使用python来调用CAN通讯的DLL实现方法就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持。