学习笔记之----在Qt下的串口读写

Tags: linux Qt 串口

这几天一直纠结于Qt下的串口读写，我把疑问和解决过程陆续记录下来，怕以后忘记了嘿嘿。 欢迎大家一起学习分享经验！

因为Qt没有提供给我们现成的串口类，在Qt下想实现串口读写操作，有两种办法：

1.自定义串口类

通常我们都是使用写好的第三方串口类，当然了有linux下与window下两个版本，我是做Linux下开发的，所以这里就先提供Linux下的串口类资源，网上相关的资源很多很多，baidu google一下就好。

几个类之间的关系图

在Linux下：我们需要

qextserialbase.cpp和qextserialbase.h 以及posix_qextserialport.cpp和posix_qextserialport.h

使用查询Polling方式。

代码资源如下：

/** * @file qextserialenumerator.cpp * @author Michał Policht * @see QextSerialEnumerator */ #include "qextserialenumerator.h" #include <objbase.h> #include <initguid.h> #ifdef _TTY_WIN_ //this is serial port GUID #ifndef GUID_CLASS_COMPORT DEFINE_GUID(GUID_CLASS_COMPORT, 0x86e0d1e0L, 0x8089, 0x11d0, 0x9c, 0xe4, 0x08, 0x00, 0x3e, 0x30, 0x1f, 0x73); #endif /* Gordon Schumacher's macros for TCHAR -> QString conversions and vice versa */ #ifdef UNICODE #define QStringToTCHAR(x) (wchar_t*) x.utf16() #define PQStringToTCHAR(x) (wchar_t*) x->utf16() #define TCHARToQString(x) QString::fromUtf16((ushort*)(x)) #define TCHARToQStringN(x,y) QString::fromUtf16((ushort*)(x),(y)) #else #define QStringToTCHAR(x) x.local8Bit().constData() #define PQStringToTCHAR(x) x->local8Bit().constData() #define TCHARToQString(x) QString::fromLocal8Bit((x)) #define TCHARToQStringN(x,y) QString::fromLocal8Bit((x),(y)) #endif /*UNICODE*/ //static QString QextSerialEnumerator::getRegKeyValue(HKEY key, LPCTSTR property) { DWORD size = 0; RegQueryValueEx(key, property, NULL, NULL, NULL, & size); BYTE * buff = new BYTE[size]; if (RegQueryValueEx(key, property, NULL, NULL, buff, & size) == ERROR_SUCCESS) { return TCHARToQStringN(buff, size); delete [] buff; } else { qWarning("QextSerialEnumerator::getRegKeyValue: can not obtain value from registry"); delete [] buff; return QString(); } } //static QString QextSerialEnumerator::getDeviceProperty(HDEVINFO devInfo, PSP_DEVINFO_DATA devData, DWORD property) { DWORD buffSize = 0; SetupDiGetDeviceRegistryProperty(devInfo, devData, property, NULL, NULL, 0, & buffSize); BYTE * buff = new BYTE[buffSize]; if (!SetupDiGetDeviceRegistryProperty(devInfo, devData, property, NULL, buff, buffSize, NULL)) qCritical("Can not obtain property: %ld from registry", property); QString result = TCHARToQString(buff); delete [] buff; return result; } //static void QextSerialEnumerator::setupAPIScan(QList<QextPortInfo> & infoList) { HDEVINFO devInfo = INVALID_HANDLE_VALUE; GUID * guidDev = (GUID *) & GUID_CLASS_COMPORT; devInfo = SetupDiGetClassDevs(guidDev, NULL, NULL, DIGCF_PRESENT | DIGCF_DEVICEINTERFACE); if(devInfo == INVALID_HANDLE_VALUE) { qCritical("SetupDiGetClassDevs failed. Error code: %ld", GetLastError()); return; } //enumerate the devices bool ok = true; SP_DEVICE_INTERFACE_DATA ifcData; ifcData.cbSize = sizeof(SP_DEVICE_INTERFACE_DATA); SP_DEVICE_INTERFACE_DETAIL_DATA * detData = NULL; DWORD detDataSize = 0; DWORD oldDetDataSize = 0; for (DWORD i = 0; ok; i++) { ok = SetupDiEnumDeviceInterfaces(devInfo, NULL, guidDev, i, &ifcData); if (ok) { SP_DEVINFO_DATA devData = {sizeof(SP_DEVINFO_DATA)}; //check for required detData size SetupDiGetDeviceInterfaceDetail(devInfo, & ifcData, NULL, 0, & detDataSize, & devData); //if larger than old detData size then reallocate the buffer if (detDataSize > oldDetDataSize) { delete [] detData; detData = (SP_DEVICE_INTERFACE_DETAIL_DATA *) new char[detDataSize]; detData->cbSize = sizeof(SP_DEVICE_INTERFACE_DETAIL_DATA); oldDetDataSize = detDataSize; } //check the details if (SetupDiGetDeviceInterfaceDetail(devInfo, & ifcData, detData, detDataSize, NULL, & devData)) { // Got a device. Get the details. QextPortInfo info; info.friendName = getDeviceProperty(devInfo, & devData, SPDRP_FRIENDLYNAME); info.physName = getDeviceProperty(devInfo, & devData, SPDRP_PHYSICAL_DEVICE_OBJECT_NAME); info.enumName = getDeviceProperty(devInfo, & devData, SPDRP_ENUMERATOR_NAME); //anyway, to get the port name we must still open registry directly :( ??? //Eh... HKEY devKey = SetupDiOpenDevRegKey(devInfo, & devData, DICS_FLAG_GLOBAL, 0, DIREG_DEV, KEY_READ); info.portName = getRegKeyValue(devKey, TEXT("PortName")); RegCloseKey(devKey); infoList.append(info); } else { qCritical("SetupDiGetDeviceInterfaceDetail failed. Error code: %ld", GetLastError()); delete [] detData; return; } } else { if (GetLastError() != ERROR_NO_MORE_ITEMS) { delete [] detData; qCritical("SetupDiEnumDeviceInterfaces failed. Error code: %ld", GetLastError()); return; } } } delete [] detData; } #endif /*_TTY_WIN_*/ //static QList<QextPortInfo> QextSerialEnumerator::getPorts() { QList<QextPortInfo> ports; #ifdef _TTY_WIN_ OSVERSIONINFO vi; vi.dwOSVersionInfoSize = sizeof(vi); if (!::GetVersionEx(&vi)) { qCritical("Could not get OS version."); return ports; } // Handle windows 9x and NT4 specially if (vi.dwMajorVersion < 5) { qCritical("Enumeration for this version of Windows is not implemented yet"); /* if (vi.dwPlatformId == VER_PLATFORM_WIN32_NT) EnumPortsWNt4(ports); else EnumPortsW9x(ports);*/ } else //w2k or later setupAPIScan(ports); #endif /*_TTY_WIN_*/ #ifdef _TTY_POSIX_ qCritical("Enumeration for POSIX systems is not implemented yet."); #endif /*_TTY_POSIX_*/ return ports; }

/*! /class Posix_QextSerialPort /version 1.0.0 /author Stefan Sander /author Michal Policht A cross-platform serial port class. This class encapsulates the POSIX portion of QextSerialPort. The user will be notified of errors and possible portability conflicts at run-time by default - this behavior can be turned off by defining _TTY_NOWARN_ (to turn off all warnings) or _TTY_NOWARN_PORT_ (to turn off portability warnings) in the project. Note that _TTY_NOWARN_ will also turn off portability warnings. */ #include <stdio.h> #include "posix_qextserialport.h" /*! /fn Posix_QextSerialPort::Posix_QextSerialPort() Default constructor. Note that the name of the device used by a QextSerialPort constructed with this constructor will be determined by #defined constants, or lack thereof - the default behavior is the same as _TTY_LINUX_. Possible naming conventions and their associated constants are: /verbatim Constant Used By Naming Convention ---------- ------------- ------------------------ _TTY_WIN_ Windows COM1, COM2 _TTY_IRIX_ SGI/IRIX /dev/ttyf1, /dev/ttyf2 _TTY_HPUX_ HP-UX /dev/tty1p0, /dev/tty2p0 _TTY_SUN_ SunOS/Solaris /dev/ttya, /dev/ttyb _TTY_DIGITAL_ Digital UNIX /dev/tty01, /dev/tty02 _TTY_FREEBSD_ FreeBSD /dev/ttyd0, /dev/ttyd1 _TTY_LINUX_ Linux /dev/ttyS0, /dev/ttyS1 <none> Linux /dev/ttyS0, /dev/ttyS1 /endverbatim This constructor assigns the device name to the name of the first port on the specified system. See the other constructors if you need to open a different port. */ Posix_QextSerialPort::Posix_QextSerialPort() : QextSerialBase() { Posix_File=new QFile(); } /*! /fn Posix_QextSerialPort::Posix_QextSerialPort(const Posix_QextSerialPort&) Copy constructor. */ Posix_QextSerialPort::Posix_QextSerialPort(const Posix_QextSerialPort& s) : QextSerialBase(s.port) { setOpenMode(s.openMode()); port = s.port; Settings.BaudRate=s.Settings.BaudRate; Settings.DataBits=s.Settings.DataBits; Settings.Parity=s.Settings.Parity; Settings.StopBits=s.Settings.StopBits; Settings.FlowControl=s.Settings.FlowControl; lastErr=s.lastErr; Posix_File=new QFile(); Posix_File=s.Posix_File; memcpy(&Posix_Timeout, &s.Posix_Timeout, sizeof(struct timeval)); memcpy(&Posix_Copy_Timeout, &s.Posix_Copy_Timeout, sizeof(struct timeval)); memcpy(&Posix_CommConfig, &s.Posix_CommConfig, sizeof(struct termios)); } /*! /fn Posix_QextSerialPort::Posix_QextSerialPort(const QString & name) Constructs a serial port attached to the port specified by name. name is the name of the device, which is windowsystem-specific, e.g."COM1" or "/dev/ttyS0". */ Posix_QextSerialPort::Posix_QextSerialPort(const QString & name, QextSerialBase::QueryMode mode) : QextSerialBase(name) { Posix_File=new QFile(); setQueryMode(mode); init(); } /*! /fn Posix_QextSerialPort::Posix_QextSerialPort(const PortSettings& settings) Constructs a port with default name and specified settings. */ Posix_QextSerialPort::Posix_QextSerialPort(const PortSettings& settings, QextSerialBase::QueryMode mode) : QextSerialBase() { setBaudRate(settings.BaudRate); setDataBits(settings.DataBits); setParity(settings.Parity); setStopBits(settings.StopBits); setFlowControl(settings.FlowControl); Posix_File=new QFile(); setTimeout(settings.Timeout_Millisec); setQueryMode(mode); init(); } /*! /fn Posix_QextSerialPort::Posix_QextSerialPort(const QString & name, const PortSettings& settings) Constructs a port with specified name and settings. */ Posix_QextSerialPort::Posix_QextSerialPort(const QString & name, const PortSettings& settings, QextSerialBase::QueryMode mode) : QextSerialBase(name) { setBaudRate(settings.BaudRate); setDataBits(settings.DataBits); setParity(settings.Parity); setStopBits(settings.StopBits); setFlowControl(settings.FlowControl); Posix_File=new QFile(); setTimeout(settings.Timeout_Millisec); setQueryMode(mode); init(); } /*! /fn Posix_QextSerialPort& Posix_QextSerialPort::operator=(const Posix_QextSerialPort& s) Override the = operator. */ Posix_QextSerialPort& Posix_QextSerialPort::operator=(const Posix_QextSerialPort& s) { setOpenMode(s.openMode()); port = s.port; Settings.BaudRate=s.Settings.BaudRate; Settings.DataBits=s.Settings.DataBits; Settings.Parity=s.Settings.Parity; Settings.StopBits=s.Settings.StopBits; Settings.FlowControl=s.Settings.FlowControl; lastErr=s.lastErr; Posix_File=s.Posix_File; memcpy(&Posix_Timeout, &(s.Posix_Timeout), sizeof(struct timeval)); memcpy(&Posix_Copy_Timeout, &(s.Posix_Copy_Timeout), sizeof(struct timeval)); memcpy(&Posix_CommConfig, &(s.Posix_CommConfig), sizeof(struct termios)); return *this; } void Posix_QextSerialPort::init() { if (queryMode() == QextSerialBase::EventDriven) qWarning("POSIX doesn't have event driven mechanism implemented yet"); } /*! /fn Posix_QextSerialPort::~Posix_QextSerialPort() Standard destructor. */ Posix_QextSerialPort::~Posix_QextSerialPort() { if (isOpen()) { close(); } Posix_File->close(); delete Posix_File; } /*! /fn void Posix_QextSerialPort::setBaudRate(BaudRateType baudRate) Sets the baud rate of the serial port. Note that not all rates are applicable on all platforms. The following table shows translations of the various baud rate constants on Windows(including NT/2000) and POSIX platforms. Speeds marked with an * are speeds that are usable on both Windows and POSIX. /note BAUD76800 may not be supported on all POSIX systems. SGI/IRIX systems do not support BAUD1800. /verbatim RATE Windows Speed POSIX Speed ----------- ------------- ----------- BAUD50 110 50 BAUD75 110 75 *BAUD110 110 110 BAUD134 110 134.5 BAUD150 110 150 BAUD200 110 200 *BAUD300 300 300 *BAUD600 600 600 *BAUD1200 1200 1200 BAUD1800 1200 1800 *BAUD2400 2400 2400 *BAUD4800 4800 4800 *BAUD9600 9600 9600 BAUD14400 14400 9600 *BAUD19200 19200 19200 *BAUD38400 38400 38400 BAUD56000 56000 38400 *BAUD57600 57600 57600 BAUD76800 57600 76800 *BAUD115200 115200 115200 BAUD128000 128000 115200 BAUD256000 256000 115200 /endverbatim */ void Posix_QextSerialPort::setBaudRate(BaudRateType baudRate) { LOCK_MUTEX(); if (Settings.BaudRate!=baudRate) { switch (baudRate) { case BAUD14400: Settings.BaudRate=BAUD9600; break; case BAUD56000: Settings.BaudRate=BAUD38400; break; case BAUD76800: #ifndef B76800 Settings.BaudRate=BAUD57600; #else Settings.BaudRate=baudRate; #endif break; case BAUD128000: case BAUD256000: Settings.BaudRate=BAUD115200; break; default: Settings.BaudRate=baudRate; break; } } if (isOpen()) { switch (baudRate) { /*50 baud*/ case BAUD50: TTY_PORTABILITY_WARNING("Posix_QextSerialPort Portability Warning: Windows does not support 50 baud operation."); #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B50; #else cfsetispeed(&Posix_CommConfig, B50); cfsetospeed(&Posix_CommConfig, B50); #endif break; /*75 baud*/ case BAUD75: TTY_PORTABILITY_WARNING("Posix_QextSerialPort Portability Warning: Windows does not support 75 baud operation."); #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B75; #else cfsetispeed(&Posix_CommConfig, B75); cfsetospeed(&Posix_CommConfig, B75); #endif break; /*110 baud*/ case BAUD110: #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B110; #else cfsetispeed(&Posix_CommConfig, B110); cfsetospeed(&Posix_CommConfig, B110); #endif break; /*134.5 baud*/ case BAUD134: TTY_PORTABILITY_WARNING("Posix_QextSerialPort Portability Warning: Windows does not support 134.5 baud operation."); #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B134; #else cfsetispeed(&Posix_CommConfig, B134); cfsetospeed(&Posix_CommConfig, B134); #endif break; /*150 baud*/ case BAUD150: TTY_PORTABILITY_WARNING("Posix_QextSerialPort Portability Warning: Windows does not support 150 baud operation."); #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B150; #else cfsetispeed(&Posix_CommConfig, B150); cfsetospeed(&Posix_CommConfig, B150); #endif break; /*200 baud*/ case BAUD200: TTY_PORTABILITY_WARNING("Posix_QextSerialPort Portability Warning: Windows does not support 200 baud operation."); #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B200; #else cfsetispeed(&Posix_CommConfig, B200); cfsetospeed(&Posix_CommConfig, B200); #endif break; /*300 baud*/ case BAUD300: #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B300; #else cfsetispeed(&Posix_CommConfig, B300); cfsetospeed(&Posix_CommConfig, B300); #endif break; /*600 baud*/ case BAUD600: #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B600; #else cfsetispeed(&Posix_CommConfig, B600); cfsetospeed(&Posix_CommConfig, B600); #endif break; /*1200 baud*/ case BAUD1200: #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B1200; #else cfsetispeed(&Posix_CommConfig, B1200); cfsetospeed(&Posix_CommConfig, B1200); #endif break; /*1800 baud*/ case BAUD1800: TTY_PORTABILITY_WARNING("Posix_QextSerialPort Portability Warning: Windows and IRIX do not support 1800 baud operation."); #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B1800; #else cfsetispeed(&Posix_CommConfig, B1800); cfsetospeed(&Posix_CommConfig, B1800); #endif break; /*2400 baud*/ case BAUD2400: #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B2400; #else cfsetispeed(&Posix_CommConfig, B2400); cfsetospeed(&Posix_CommConfig, B2400); #endif break; /*4800 baud*/ case BAUD4800: #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B4800; #else cfsetispeed(&Posix_CommConfig, B4800); cfsetospeed(&Posix_CommConfig, B4800); #endif break; /*9600 baud*/ case BAUD9600: #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B9600; #else cfsetispeed(&Posix_CommConfig, B9600); cfsetospeed(&Posix_CommConfig, B9600); #endif break; /*14400 baud*/ case BAUD14400: TTY_WARNING("Posix_QextSerialPort: POSIX does not support 14400 baud operation. Switching to 9600 baud."); #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B9600; #else cfsetispeed(&Posix_CommConfig, B9600); cfsetospeed(&Posix_CommConfig, B9600); #endif break; /*19200 baud*/ case BAUD19200: #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B19200; #else cfsetispeed(&Posix_CommConfig, B19200); cfsetospeed(&Posix_CommConfig, B19200); #endif break; /*38400 baud*/ case BAUD38400: #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B38400; #else cfsetispeed(&Posix_CommConfig, B38400); cfsetospeed(&Posix_CommConfig, B38400); #endif break; /*56000 baud*/ case BAUD56000: TTY_WARNING("Posix_QextSerialPort: POSIX does not support 56000 baud operation. Switching to 38400 baud."); #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B38400; #else cfsetispeed(&Posix_CommConfig, B38400); cfsetospeed(&Posix_CommConfig, B38400); #endif break; /*57600 baud*/ case BAUD57600: #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B57600; #else cfsetispeed(&Posix_CommConfig, B57600); cfsetospeed(&Posix_CommConfig, B57600); #endif break; /*76800 baud*/ case BAUD76800: TTY_PORTABILITY_WARNING("Posix_QextSerialPort Portability Warning: Windows and some POSIX systems do not support 76800 baud operation."); #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); #ifdef B76800 Posix_CommConfig.c_cflag|=B76800; #else TTY_WARNING("Posix_QextSerialPort: Posix_QextSerialPort was compiled without 76800 baud support. Switching to 57600 baud."); Posix_CommConfig.c_cflag|=B57600; #endif //B76800 #else //CBAUD #ifdef B76800 cfsetispeed(&Posix_CommConfig, B76800); cfsetospeed(&Posix_CommConfig, B76800); #else TTY_WARNING("Posix_QextSerialPort: Posix_QextSerialPort was compiled without 76800 baud support. Switching to 57600 baud."); cfsetispeed(&Posix_CommConfig, B57600); cfsetospeed(&Posix_CommConfig, B57600); #endif //B76800 #endif //CBAUD break; /*115200 baud*/ case BAUD115200: #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B115200; #else cfsetispeed(&Posix_CommConfig, B115200); cfsetospeed(&Posix_CommConfig, B115200); #endif break; /*128000 baud*/ case BAUD128000: TTY_WARNING("Posix_QextSerialPort: POSIX does not support 128000 baud operation. Switching to 115200 baud."); #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B115200; #else cfsetispeed(&Posix_CommConfig, B115200); cfsetospeed(&Posix_CommConfig, B115200); #endif break; /*256000 baud*/ case BAUD256000: TTY_WARNING("Posix_QextSerialPort: POSIX does not support 256000 baud operation. Switching to 115200 baud."); #ifdef CBAUD Posix_CommConfig.c_cflag&=(~CBAUD); Posix_CommConfig.c_cflag|=B115200; #else cfsetispeed(&Posix_CommConfig, B115200); cfsetospeed(&Posix_CommConfig, B115200); #endif break; } tcsetattr(Posix_File->handle(), TCSAFLUSH, &Posix_CommConfig); } UNLOCK_MUTEX(); } /*! /fn void Posix_QextSerialPort::setDataBits(DataBitsType dataBits) Sets the number of data bits used by the serial port. Possible values of dataBits are: /verbatim DATA_5 5 data bits DATA_6 6 data bits DATA_7 7 data bits DATA_8 8 data bits /endverbatim /note This function is subject to the following restrictions: /par 5 data bits cannot be used with 2 stop bits. /par 8 data bits cannot be used with space parity on POSIX systems. */ void Posix_QextSerialPort::setDataBits(DataBitsType dataBits) { LOCK_MUTEX(); if (Settings.DataBits!=dataBits) { if ((Settings.StopBits==STOP_2 && dataBits==DATA_5) || (Settings.StopBits==STOP_1_5 && dataBits!=DATA_5) || (Settings.Parity==PAR_SPACE && dataBits==DATA_8)) { } else { Settings.DataBits=dataBits; } } if (isOpen()) { switch(dataBits) { /*5 data bits*/ case DATA_5: if (Settings.StopBits==STOP_2) { TTY_WARNING("Posix_QextSerialPort: 5 Data bits cannot be used with 2 stop bits."); } else { Settings.DataBits=dataBits; Posix_CommConfig.c_cflag&=(~CSIZE); Posix_CommConfig.c_cflag|=CS5; tcsetattr(Posix_File->handle(), TCSAFLUSH, &Posix_CommConfig); } break; /*6 data bits*/ case DATA_6: if (Settings.StopBits==STOP_1_5) { TTY_WARNING("Posix_QextSerialPort: 6 Data bits cannot be used with 1.5 stop bits."); } else { Settings.DataBits=dataBits; Posix_CommConfig.c_cflag&=(~CSIZE); Posix_CommConfig.c_cflag|=CS6; tcsetattr(Posix_File->handle(), TCSAFLUSH, &Posix_CommConfig); } break; /*7 data bits*/ case DATA_7: if (Settings.StopBits==STOP_1_5) { TTY_WARNING("Posix_QextSerialPort: 7 Data bits cannot be used with 1.5 stop bits."); } else { Settings.DataBits=dataBits; Posix_CommConfig.c_cflag&=(~CSIZE); Posix_CommConfig.c_cflag|=CS7; tcsetattr(Posix_File->handle(), TCSAFLUSH, &Posix_CommConfig); } break; /*8 data bits*/ case DATA_8: if (Settings.StopBits==STOP_1_5) { TTY_WARNING("Posix_QextSerialPort: 8 Data bits cannot be used with 1.5 stop bits."); } else { Settings.DataBits=dataBits; Posix_CommConfig.c_cflag&=(~CSIZE); Posix_CommConfig.c_cflag|=CS8; tcsetattr(Posix_File->handle(), TCSAFLUSH, &Posix_CommConfig); } break; } } UNLOCK_MUTEX(); } /*! /fn void Posix_QextSerialPort::setParity(ParityType parity) Sets the parity associated with the serial port. The possible values of parity are: /verbatim PAR_SPACE Space Parity PAR_MARK Mark Parity PAR_NONE No Parity PAR_EVEN Even Parity PAR_ODD Odd Parity /endverbatim /note This function is subject to the following limitations: /par POSIX systems do not support mark parity. /par POSIX systems support space parity only if tricked into doing so, and only with fewer than 8 data bits. Use space parity very carefully with POSIX systems. */ void Posix_QextSerialPort::setParity(ParityType parity) { LOCK_MUTEX(); if (Settings.Parity!=parity) { if (parity==PAR_MARK || (parity==PAR_SPACE && Settings.DataBits==DATA_8)) { } else { Settings.Parity=parity; } } if (isOpen()) { switch (parity) { /*space parity*/ case PAR_SPACE: if (Settings.DataBits==DATA_8) { TTY_PORTABILITY_WARNING("Posix_QextSerialPort: Space parity is only supported in POSIX with 7 or fewer data bits"); } else { /*space parity not directly supported - add an extra data bit to simulate it*/ Posix_CommConfig.c_cflag&=~(PARENB|CSIZE); switch(Settings.DataBits) { case DATA_5: Settings.DataBits=DATA_6; Posix_CommConfig.c_cflag|=CS6; break; case DATA_6: Settings.DataBits=DATA_7; Posix_CommConfig.c_cflag|=CS7; break; case DATA_7: Settings.DataBits=DATA_8; Posix_CommConfig.c_cflag|=CS8; break; case DATA_8: break; } tcsetattr(Posix_File->handle(), TCSAFLUSH, &Posix_CommConfig); } break; /*mark parity - WINDOWS ONLY*/ case PAR_MARK: TTY_WARNING("Posix_QextSerialPort: Mark parity is not supported by POSIX."); break; /*no parity*/ case PAR_NONE: Posix_CommConfig.c_cflag&=(~PARENB); tcsetattr(Posix_File->handle(), TCSAFLUSH, &Posix_CommConfig); break; /*even parity*/ case PAR_EVEN: Posix_CommConfig.c_cflag&=(~PARODD); Posix_CommConfig.c_cflag|=PARENB; tcsetattr(Posix_File->handle(), TCSAFLUSH, &Posix_CommConfig); break; /*odd parity*/ case PAR_ODD: Posix_CommConfig.c_cflag|=(PARENB|PARODD); tcsetattr(Posix_File->handle(), TCSAFLUSH, &Posix_CommConfig); break; } } UNLOCK_MUTEX(); } /*! /fn void Posix_QextSerialPort::setStopBits(StopBitsType stopBits) Sets the number of stop bits used by the serial port. Possible values of stopBits are: /verbatim STOP_1 1 stop bit STOP_1_5 1.5 stop bits STOP_2 2 stop bits /endverbatim /note This function is subject to the following restrictions: /par 2 stop bits cannot be used with 5 data bits. /par POSIX does not support 1.5 stop bits. */ void Posix_QextSerialPort::setStopBits(StopBitsType stopBits) { LOCK_MUTEX(); if (Settings.StopBits!=stopBits) { if ((Settings.DataBits==DATA_5 && stopBits==STOP_2) || stopBits==STOP_1_5) {} else { Settings.StopBits=stopBits; } } if (isOpen()) { switch (stopBits) { /*one stop bit*/ case STOP_1: Settings.StopBits=stopBits; Posix_CommConfig.c_cflag&=(~CSTOPB); tcsetattr(Posix_File->handle(), TCSAFLUSH, &Posix_CommConfig); break; /*1.5 stop bits*/ case STOP_1_5: TTY_WARNING("Posix_QextSerialPort: 1.5 stop bit operation is not supported by POSIX."); break; /*two stop bits*/ case STOP_2: if (Settings.DataBits==DATA_5) { TTY_WARNING("Posix_QextSerialPort: 2 stop bits cannot be used with 5 data bits"); } else { Settings.StopBits=stopBits; Posix_CommConfig.c_cflag|=CSTOPB; tcsetattr(Posix_File->handle(), TCSAFLUSH, &Posix_CommConfig); } break; } } UNLOCK_MUTEX(); } /*! /fn void Posix_QextSerialPort::setFlowControl(FlowType flow) Sets the flow control used by the port. Possible values of flow are: /verbatim FLOW_OFF No flow control FLOW_HARDWARE Hardware (RTS/CTS) flow control FLOW_XONXOFF Software (XON/XOFF) flow control /endverbatim /note FLOW_HARDWARE may not be supported on all versions of UNIX. In cases where it is unsupported, FLOW_HARDWARE is the same as FLOW_OFF. */ void Posix_QextSerialPort::setFlowControl(FlowType flow) { LOCK_MUTEX(); if (Settings.FlowControl!=flow) { Settings.FlowControl=flow; } if (isOpen()) { switch(flow) { /*no flow control*/ case FLOW_OFF: Posix_CommConfig.c_cflag&=(~CRTSCTS); Posix_CommConfig.c_iflag&=(~(IXON|IXOFF|IXANY)); tcsetattr(Posix_File->handle(), TCSAFLUSH, &Posix_CommConfig); break; /*software (XON/XOFF) flow control*/ case FLOW_XONXOFF: Posix_CommConfig.c_cflag&=(~CRTSCTS); Posix_CommConfig.c_iflag|=(IXON|IXOFF|IXANY); tcsetattr(Posix_File->handle(), TCSAFLUSH, &Posix_CommConfig); break; case FLOW_HARDWARE: Posix_CommConfig.c_cflag|=CRTSCTS; Posix_CommConfig.c_iflag&=(~(IXON|IXOFF|IXANY)); tcsetattr(Posix_File->handle(), TCSAFLUSH, &Posix_CommConfig); break; } } UNLOCK_MUTEX(); } /*! /fn void Posix_QextSerialPort::setTimeout(ulong sec); Sets the read and write timeouts for the port to millisec milliseconds. Note that this is a per-character timeout, i.e. the port will wait this long for each individual character, not for the whole read operation. This timeout also applies to the bytesWaiting() function. /note POSIX does not support millisecond-level control for I/O timeout values. Any timeout set using this function will be set to the next lowest tenth of a second for the purposes of detecting read or write timeouts. For example a timeout of 550 milliseconds will be seen by the class as a timeout of 500 milliseconds for the purposes of reading and writing the port. However millisecond-level control is allowed by the select() system call, so for example a 550-millisecond timeout will be seen as 550 milliseconds on POSIX systems for the purpose of detecting available bytes in the read buffer. */ void Posix_QextSerialPort::setTimeout(long millisec) { LOCK_MUTEX(); Settings.Timeout_Millisec = millisec; Posix_Copy_Timeout.tv_sec = millisec / 1000; Posix_Copy_Timeout.tv_usec = millisec % 1000; if (isOpen()) { tcgetattr(Posix_File->handle(), &Posix_CommConfig); Posix_CommConfig.c_cc[VTIME] = millisec/100; tcsetattr(Posix_File->handle(), TCSAFLUSH, &Posix_CommConfig); } UNLOCK_MUTEX(); } /*! /fn bool Posix_QextSerialPort::open(OpenMode mode) Opens the serial port associated to this class. This function has no effect if the port associated with the class is already open. The port is also configured to the current settings, as stored in the Settings structure. */ bool Posix_QextSerialPort::open(OpenMode mode) { LOCK_MUTEX(); if (mode == QIODevice::NotOpen) return isOpen(); if (!isOpen()) { /*open the port*/ Posix_File->setFileName(port); qDebug("Trying to open File"); if (Posix_File->open(QIODevice::ReadWrite|QIODevice::Unbuffered)) { qDebug("Opened File succesfully"); /*set open mode*/ QIODevice::open(mode); /*configure port settings*/ tcgetattr(Posix_File->handle(), &Posix_CommConfig); /*set up other port settings*/ Posix_CommConfig.c_cflag|=CREAD|CLOCAL; Posix_CommConfig.c_lflag&=(~(ICANON|ECHO|ECHOE|ECHOK|ECHONL|ISIG)); Posix_CommConfig.c_iflag&=(~(INPCK|IGNPAR|PARMRK|ISTRIP|ICRNL|IXANY)); Posix_CommConfig.c_oflag&=(~OPOST); Posix_CommConfig.c_cc[VMIN]=0; Posix_CommConfig.c_cc[VINTR] = _POSIX_VDISABLE; Posix_CommConfig.c_cc[VQUIT] = _POSIX_VDISABLE; Posix_CommConfig.c_cc[VSTART] = _POSIX_VDISABLE; Posix_CommConfig.c_cc[VSTOP] = _POSIX_VDISABLE; Posix_CommConfig.c_cc[VSUSP] = _POSIX_VDISABLE; setBaudRate(Settings.BaudRate); setDataBits(Settings.DataBits); setParity(Settings.Parity); setStopBits(Settings.StopBits); setFlowControl(Settings.FlowControl); setTimeout(Settings.Timeout_Sec, Settings.Timeout_Millisec); tcsetattr(Posix_File->handle(), TCSAFLUSH, &Posix_CommConfig); } else { qDebug("Could not open File! Error code : %d", Posix_File->error()); } } UNLOCK_MUTEX(); return isOpen(); } /*! /fn void Posix_QextSerialPort::close() Closes a serial port. This function has no effect if the serial port associated with the class is not currently open. */ void Posix_QextSerialPort::close() { LOCK_MUTEX(); Posix_File->close(); QIODevice::close(); UNLOCK_MUTEX(); } /*! /fn void Posix_QextSerialPort::flush() Flushes all pending I/O to the serial port. This function has no effect if the serial port associated with the class is not currently open. */ void Posix_QextSerialPort::flush() { LOCK_MUTEX(); if (isOpen()) { Posix_File->flush(); } UNLOCK_MUTEX(); } /*! /fn qint64 Posix_QextSerialPort::size() const This function will return the number of bytes waiting in the receive queue of the serial port. It is included primarily to provide a complete QIODevice interface, and will not record errors in the lastErr member (because it is const). This function is also not thread-safe - in multithreading situations, use Posix_QextSerialPort::bytesWaiting() instead. */ qint64 Posix_QextSerialPort::size() const { int numBytes; if (ioctl(Posix_File->handle(), FIONREAD, &numBytes)<0) { numBytes=0; } return (qint64)numBytes; } /*! /fn qint64 Posix_QextSerialPort::bytesAvailable() Returns the number of bytes waiting in the port's receive queue. This function will return 0 if the port is not currently open, or -1 on error. Error information can be retrieved by calling Posix_QextSerialPort::getLastError(). */ qint64 Posix_QextSerialPort::bytesAvailable() { LOCK_MUTEX(); if (isOpen()) { int bytesQueued; fd_set fileSet; FD_ZERO(&fileSet); FD_SET(Posix_File->handle(), &fileSet); /*on Linux systems the Posix_Timeout structure will be altered by the select() call. Make sure we use the right timeout values*/ //memcpy(&Posix_Timeout, &Posix_Copy_Timeout, sizeof(struct timeval)); Posix_Timeout = Posix_Copy_Timeout; int n=select(Posix_File->handle()+1, &fileSet, NULL, &fileSet, &Posix_Timeout); if (!n) { lastErr=E_PORT_TIMEOUT; UNLOCK_MUTEX(); return -1; } if (n==-1 || ioctl(Posix_File->handle(), FIONREAD, &bytesQueued)==-1) { translateError(errno); UNLOCK_MUTEX(); return -1; } lastErr=E_NO_ERROR; UNLOCK_MUTEX(); return bytesQueued + QIODevice::bytesAvailable(); } UNLOCK_MUTEX(); return 0; } /*! /fn void Posix_QextSerialPort::ungetChar(char) This function is included to implement the full QIODevice interface, and currently has no purpose within this class. This function is meaningless on an unbuffered device and currently only prints a warning message to that effect. */ void Posix_QextSerialPort::ungetChar(char) { /*meaningless on unbuffered sequential device - return error and print a warning*/ TTY_WARNING("Posix_QextSerialPort: ungetChar() called on an unbuffered sequential device - operation is meaningless"); } /*! /fn void Posix_QextSerialPort::translateError(ulong error) Translates a system-specific error code to a QextSerialPort error code. Used internally. */ void Posix_QextSerialPort::translateError(ulong error) { switch (error) { case EBADF: case ENOTTY: lastErr=E_INVALID_FD; break; case EINTR: lastErr=E_CAUGHT_NON_BLOCKED_SIGNAL; break; case ENOMEM: lastErr=E_NO_MEMORY; break; } } /*! /fn void Posix_QextSerialPort::setDtr(bool set) Sets DTR line to the requested state (high by default). This function will have no effect if the port associated with the class is not currently open. */ void Posix_QextSerialPort::setDtr(bool set) { LOCK_MUTEX(); if (isOpen()) { int status; ioctl(Posix_File->handle(), TIOCMGET, &status); if (set) { status|=TIOCM_DTR; } else { status&=~TIOCM_DTR; } ioctl(Posix_File->handle(), TIOCMSET, &status); } UNLOCK_MUTEX(); } /*! /fn void Posix_QextSerialPort::setRts(bool set) Sets RTS line to the requested state (high by default). This function will have no effect if the port associated with the class is not currently open. */ void Posix_QextSerialPort::setRts(bool set) { LOCK_MUTEX(); if (isOpen()) { int status; ioctl(Posix_File->handle(), TIOCMGET, &status); if (set) { status|=TIOCM_RTS; } else { status&=~TIOCM_RTS; } ioctl(Posix_File->handle(), TIOCMSET, &status); } UNLOCK_MUTEX(); } /*! /fn unsigned long Posix_QextSerialPort::lineStatus() returns the line status as stored by the port function. This function will retrieve the states of the following lines: DCD, CTS, DSR, and RI. On POSIX systems, the following additional lines can be monitored: DTR, RTS, Secondary TXD, and Secondary RXD. The value returned is an unsigned long with specific bits indicating which lines are high. The following constants should be used to examine the states of individual lines: /verbatim Mask Line ------ ---- LS_CTS CTS LS_DSR DSR LS_DCD DCD LS_RI RI LS_RTS RTS (POSIX only) LS_DTR DTR (POSIX only) LS_ST Secondary TXD (POSIX only) LS_SR Secondary RXD (POSIX only) /endverbatim This function will return 0 if the port associated with the class is not currently open. */ unsigned long Posix_QextSerialPort::lineStatus() { unsigned long Status=0, Temp=0; LOCK_MUTEX(); if (isOpen()) { ioctl(Posix_File->handle(), TIOCMGET, &Temp); if (Temp&TIOCM_CTS) { Status|=LS_CTS; } if (Temp&TIOCM_DSR) { Status|=LS_DSR; } if (Temp&TIOCM_RI) { Status|=LS_RI; } if (Temp&TIOCM_CD) { Status|=LS_DCD; } if (Temp&TIOCM_DTR) { Status|=LS_DTR; } if (Temp&TIOCM_RTS) { Status|=LS_RTS; } if (Temp&TIOCM_ST) { Status|=LS_ST; } if (Temp&TIOCM_SR) { Status|=LS_SR; } } UNLOCK_MUTEX(); return Status; } /*! /fn qint64 Posix_QextSerialPort::readData(char * data, qint64 maxSize) Reads a block of data from the serial port. This function will read at most maxSize bytes from the serial port and place them in the buffer pointed to by data. Return value is the number of bytes actually read, or -1 on error. /warning before calling this function ensure that serial port associated with this class is currently open (use isOpen() function to check if port is open). */ qint64 Posix_QextSerialPort::readData(char * data, qint64 maxSize) { LOCK_MUTEX(); int retVal=0; retVal=Posix_File->read(data, maxSize); if (retVal==-1) lastErr=E_READ_FAILED; UNLOCK_MUTEX(); return retVal; } /*! /fn qint64 Posix_QextSerialPort::writeData(const char * data, qint64 maxSize) Writes a block of data to the serial port. This function will write maxSize bytes from the buffer pointed to by data to the serial port. Return value is the number of bytes actually written, or -1 on error. /warning before calling this function ensure that serial port associated with this class is currently open (use isOpen() function to check if port is open). */ qint64 Posix_QextSerialPort::writeData(const char * data, qint64 maxSize) { LOCK_MUTEX(); int retVal=0; retVal=Posix_File->write(data, maxSize); if (retVal==-1) lastErr=E_WRITE_FAILED; UNLOCK_MUTEX(); return retVal; }

更多更详细资源来源于www.yafeilinux.com。

2.自定义MyQThread类继承QThread, 通过调用线程来实现，读写串口的操作函数写在run()里。

在run()里可以使用linux下的write() ,open() ,read()等函数对设备文件fd直接操作，当然别忘记#include Linux下的相关头文件!