To write an interfacing program with parallel port or serial port, we need to know the base address of the corresponding port in advance. Normally the base address of LPT1 will be 0x378 and that of LPT2 will be 0x3F8. And most of the home PCs will have only one parallel port with base address 0x378.
To write an interfacing program with parallel port or serial port, we need to know the base address of the corresponding port in advance. Normally the base address of LPT1 will be 0x378 and that of LPT2 will be 0x3F8. And most of the home PCs will have only one parallel port with base address 0x378. If only one port is present on the system we can probably assume that the base address is 0x378. And this can be confirmed by checking the Parallel Port properties in Device Manager. To do this, right click on My Computer, select Manage. Select Device Manager from the Computer Management console. Choose Parallel Port from the device tree, right click on it and select "Properties". Go to the "Resources" tab. Here you can find the Base address of the parallel port. A sample parallel port properties window is shown below. The Base address is highlighted in red circle.
As 64 bit capable Windows versions arrive, it is very important to port inpout32.dll to it's 64 bit version so that 64 bit windows developers also can take advantage from programming parallel port. Here presents a 64 bit version inpout along with it's driver(it is also 64 bit). The 64 bit port is prepared and compiled by Phil (http://www.highrez.co.uk/). You can find the original document at http://www.highrez.co.uk/Downloads/InpOut32/default.htm.
He has ported it to Windows XP 64bit Edition (XP/2003 x64 Editions) because the 32bit driver will not install or run on x64 systems.The new version supports both 32bit and 64bit systems running under WOW64 as 32bit applicaitons, and, with a new DLL, pure x64 applicaitons.
Please click here for full description and original source code and binaries package of 32 bit version.
Installation
You need to put the driver file in your System32\Drivers folder. Make sure, if your using XP/2003 x64 Editions, to put the 64bit version there (hwinterfacedrvx64.sys) instead of the original 32bit version (hwinterface.sys)
Usage
There are examples and usage instructions for the 32bit version here . To use the pure 64bit version, all you need to do, is to link to my new InpOutx64.DLL using InpOutx64.lib. Everything else is the same.
Downloads
Driver source code (Requires the Windows 2003 DDK to build either 32bit or 64bit version)
32bit and 64bit Interface DLL source code (requires Visual Studio 2005 )
Just the binaries and libs requred to integrate with your own program.
Even though it is possible to get the parallel port base address from the properties dialogue, it will be much convenient, if we can retrieve the address of the available parallel ports programatically. DOS allowed applications to read information directly from BIOS. And that was the most popularly used method to identify parallel/Serial port address in DOS applications. But windows do not allow user mode applications to read BIOS directly. For a Windows application, this can be done with the help of a device driver only. The device driver can map the address in to the user mode process's address space and read the contents safely.
Logix4u introduces a library (hwinterface32) to access Physical memory directly from user mode application. Obviously, a device driver is involved in the process, but it is hidden from the user. Just like the Inpout32.dll , the device driver is embedded in the DLL and will be installed and configured automatically at the very first call made to the library (DLL). As a programmer, all that you need to do is, copy the DLL to relevant directory (system directory or application directory) and Call the exported functions. No driver installation, no hassles. Current Beta version of this library supports all the functions available in Inpout32.dll (Inp32() and Out32()), The library also contains functions Inpw32()/OutW32 which reads/writes 16 bit word and InpD32()/OutD32 which reads/writes 32 but DWords. Apart from I/O functions this library contains memory access functions also. Please refer the table below to see all functions supported by this library.
Function Description
short Inp32(short PortAddress) Reads a single Byte from the specified I/O address.
void Out32(short PortAddress, short data)
Writes a single Byte to the specified I/O address.
short InpW32(short PortAddress) Reads a Word from the specified I/O address.
void OutW32(short PortAddress, short data) Writes a Word to the specified I/O address.
long InpD32(short PortAddress) Reads a DWord from the specified I/O address.
void OutD32(short PortAddress, long data) Writes a DWord to the specified I/O address.
long ReadMemChar(ULONG Address) Reads a single Byte from the specified memory address.
long ReadMemShort(ULONG Address) Reads a 16 bit word from the specified memory address.
long ReadMemLong(ULONG Address) Reads a 32 bit Dword from the specified memory address.
void WriteMemChar(ULONG Address, UCHAR data ) Writes a single Byte to the specified memory address.
void WriteMemShort(ULONG Address, USHORT data) Writes a single Word to the specified memory address.
void WriteMemLong(ULONG Address, ULONG data) Writes a single DWord to the specified memory address.
Reading Parallel/Serial Port Address from BIOS
Typically, The addresses of Parallel and Serial ports present on a PC is stored in BIOS. An application can read this data to determine the presence of ports and there base addresses. The addresses of serial ports can be found starting from address 400H in BIOS. And the addresses of parallel port can be found starting from the address 408H in BIOS. The table below lists the BIOS address at which base address of each serial/parallel port can be found.
Address Port
400H Base I/O address for serial port 1 (COM 1)
402H Base I/O address for serial port 2 (COM 2)
404H Base I/O address for serial port 3 (COM 3)
406H Base I/O address for serial port 4 (COM 4)
408H Base I/O address for parallel port 1 (LPT 1)
40AH Base I/O address for parallel port 2 (LPT 2)
40CH Base I/O address for parallel port 3 (LPT 3)
It is easy to get the base address of Parallel/Serial port by reading the above addresses listed. The picture below shows the screen shot of a VB sample application which prints the base addresses of Parallel ports and serial ports with the help of hwinterface32 library.
To write an interfacing program with parallel port or serial port, we need to know the base address of the corresponding port in advance. Normally the base address of LPT1 will be 0x378 and that of LPT2 will be 0x3F8. And most of the home PCs will have only one parallel port with base address 0x378.
To write an interfacing program with parallel port or serial port, we need to know the base address of the corresponding port in advance. Normally the base address of LPT1 will be 0x378 and that of LPT2 will be 0x3F8. And most of the home PCs will have only one parallel port with base address 0x378. If only one port is present on the system we can probably assume that the base address is 0x378. And this can be confirmed by checking the Parallel Port properties in Device Manager. To do this, right click on My Computer, select Manage. Select Device Manager from the Computer Management console. Choose Parallel Port from the device tree, right click on it and select "Properties". Go to the "Resources" tab. Here you can find the Base address of the parallel port. A sample parallel port properties window is shown below. The Base address is highlighted in red circle.
Even though it is possible to get the parallel port base address from the properties dialogue, it will be much convenient, if we can retrieve the address of the available parallel ports programatically. DOS allowed applications to read information directly from BIOS. And that was the most popularly used method to identify parallel/Serial port address in DOS applications. But windows do not allow user mode applications to read BIOS directly. For a Windows application, this can be done with the help of a device driver only. The device driver can map the address in to the user mode process's address space and read the contents safely.
Logix4u introduces a library (hwinterface32) to access Physical memory directly from user mode application. Obviously, a device driver is involved in the process, but it is hidden from the user. Just like the Inpout32.dll , the device driver is embedded in the DLL and will be installed and configured automatically at the very first call made to the library (DLL). As a programmer, all that you need to do is, copy the DLL to relevant directory (system directory or application directory) and Call the exported functions. No driver installation, no hassles. Current Beta version of this library supports all the functions available in Inpout32.dll (Inp32() and Out32()), The library also contains functions Inpw32()/OutW32 which reads/writes 16 bit word and InpD32()/OutD32 which reads/writes 32 but DWords. Apart from I/O functions this library contains memory access functions also. Please refer the table below to see all functions supported by this library.
Function Description
short Inp32(short PortAddress) Reads a single Byte from the specified I/O address.
void Out32(short PortAddress, short data)
Writes a single Byte to the specified I/O address.
short InpW32(short PortAddress) Reads a Word from the specified I/O address.
void OutW32(short PortAddress, short data) Writes a Word to the specified I/O address.
long InpD32(short PortAddress) Reads a DWord from the specified I/O address.
void OutD32(short PortAddress, long data) Writes a DWord to the specified I/O address.
long ReadMemChar(ULONG Address) Reads a single Byte from the specified memory address.
long ReadMemShort(ULONG Address) Reads a 16 bit word from the specified memory address.
long ReadMemLong(ULONG Address) Reads a 32 bit Dword from the specified memory address.
void WriteMemChar(ULONG Address, UCHAR data ) Writes a single Byte to the specified memory address.
void WriteMemShort(ULONG Address, USHORT data) Writes a single Word to the specified memory address.
void WriteMemLong(ULONG Address, ULONG data) Writes a single DWord to the specified memory address.
Reading Parallel/Serial Port Address from BIOS
Typically, The addresses of Parallel and Serial ports present on a PC is stored in BIOS. An application can read this data to determine the presence of ports and there base addresses. The addresses of serial ports can be found starting from address 400H in BIOS. And the addresses of parallel port can be found starting from the address 408H in BIOS. The table below lists the BIOS address at which base address of each serial/parallel port can be found.
Address Port
400H Base I/O address for serial port 1 (COM 1)
402H Base I/O address for serial port 2 (COM 2)
404H Base I/O address for serial port 3 (COM 3)
406H Base I/O address for serial port 4 (COM 4)
408H Base I/O address for parallel port 1 (LPT 1)
40AH Base I/O address for parallel port 2 (LPT 2)
40CH Base I/O address for parallel port 3 (LPT 3)
It is easy to get the base address of Parallel/Serial port by reading the above addresses listed. The picture below shows the screen shot of a VB sample application which prints the base addresses of Parallel ports and serial ports with the help of hwinterface32 library.
To write an interfacing program with parallel port or serial port, we need to know the base address of the corresponding port in advance. Normally the base address of LPT1 will be 0x378 and that of LPT2 will be 0x3F8. And most of the home PCs will have only one parallel port with base address 0x378.
To write an interfacing program with parallel port or serial port, we need to know the base address of the corresponding port in advance. Normally the base address of LPT1 will be 0x378 and that of LPT2 will be 0x3F8. And most of the home PCs will have only one parallel port with base address 0x378. If only one port is present on the system we can probably assume that the base address is 0x378. And this can be confirmed by checking the Parallel Port properties in Device Manager. To do this, right click on My Computer, select Manage. Select Device Manager from the Computer Management console. Choose Parallel Port from the device tree, right click on it and select "Properties". Go to the "Resources" tab. Here you can find the Base address of the parallel port. A sample parallel port properties window is shown below. The Base address is highlighted in red circle.
Even though it is possible to get the parallel port base address from the properties dialogue, it will be much convenient, if we can retrieve the address of the available parallel ports programatically. DOS allowed applications to read information directly from BIOS. And that was the most popularly used method to identify parallel/Serial port address in DOS applications. But windows do not allow user mode applications to read BIOS directly. For a Windows application, this can be done with the help of a device driver only. The device driver can map the address in to the user mode process's address space and read the contents safely.
Logix4u introduces a library (hwinterface32) to access Physical memory directly from user mode application. Obviously, a device driver is involved in the process, but it is hidden from the user. Just like the Inpout32.dll , the device driver is embedded in the DLL and will be installed and configured automatically at the very first call made to the library (DLL). As a programmer, all that you need to do is, copy the DLL to relevant directory (system directory or application directory) and Call the exported functions. No driver installation, no hassles. Current Beta version of this library supports all the functions available in Inpout32.dll (Inp32() and Out32()), The library also contains functions Inpw32()/OutW32 which reads/writes 16 bit word and InpD32()/OutD32 which reads/writes 32 but DWords. Apart from I/O functions this library contains memory access functions also. Please refer the table below to see all functions supported by this library.
Function Description
short Inp32(short PortAddress) Reads a single Byte from the specified I/O address.
void Out32(short PortAddress, short data)
Writes a single Byte to the specified I/O address.
short InpW32(short PortAddress) Reads a Word from the specified I/O address.
void OutW32(short PortAddress, short data) Writes a Word to the specified I/O address.
long InpD32(short PortAddress) Reads a DWord from the specified I/O address.
void OutD32(short PortAddress, long data) Writes a DWord to the specified I/O address.
long ReadMemChar(ULONG Address) Reads a single Byte from the specified memory address.
long ReadMemShort(ULONG Address) Reads a 16 bit word from the specified memory address.
long ReadMemLong(ULONG Address) Reads a 32 bit Dword from the specified memory address.
void WriteMemChar(ULONG Address, UCHAR data ) Writes a single Byte to the specified memory address.
void WriteMemShort(ULONG Address, USHORT data) Writes a single Word to the specified memory address.
void WriteMemLong(ULONG Address, ULONG data) Writes a single DWord to the specified memory address.
Reading Parallel/Serial Port Address from BIOS
Typically, The addresses of Parallel and Serial ports present on a PC is stored in BIOS. An application can read this data to determine the presence of ports and there base addresses. The addresses of serial ports can be found starting from address 400H in BIOS. And the addresses of parallel port can be found starting from the address 408H in BIOS. The table below lists the BIOS address at which base address of each serial/parallel port can be found.
Address Port
400H Base I/O address for serial port 1 (COM 1)
402H Base I/O address for serial port 2 (COM 2)
404H Base I/O address for serial port 3 (COM 3)
406H Base I/O address for serial port 4 (COM 4)
408H Base I/O address for parallel port 1 (LPT 1)
40AH Base I/O address for parallel port 2 (LPT 2)
40CH Base I/O address for parallel port 3 (LPT 3)
It is easy to get the base address of Parallel/Serial port by reading the above addresses listed. The picture below shows the screen shot of a VB sample application which prints the base addresses of Parallel ports and serial ports with the help of hwinterface32 library.
To write an interfacing program with parallel port or serial port, we need to know the base address of the corresponding port in advance. Normally the base address of LPT1 will be 0x378 and that of LPT2 will be 0x3F8. And most of the home PCs will have only one parallel port with base address 0x378. If only one port is present on the system we can probably assume that the base address is 0x378. And this can be confirmed by checking the Parallel Port properties in Device Manager. To do this, right click on My Computer, select Manage. Select Device Manager from the Computer Management console. Choose Parallel Port from the device tree, right click on it and select "Properties". Go to the "Resources" tab. Here you can find the Base address of the parallel port. A sample parallel port properties window is shown below. The Base address is highlighted in red circle.
As 64 bit capable Windows versions arrive, it is very important to port inpout32.dll to it's 64 bit version so that 64 bit windows developers also can take advantage from programming parallel port. Here presents a 64 bit version inpout along with it's driver(it is also 64 bit). The 64 bit port is prepared and compiled by Phil (http://www.highrez.co.uk/). You can find the original document at http://www.highrez.co.uk/Downloads/InpOut32/default.htm.
He has ported it to Windows XP 64bit Edition (XP/2003 x64 Editions) because the 32bit driver will not install or run on x64 systems.The new version supports both 32bit and 64bit systems running under WOW64 as 32bit applicaitons, and, with a new DLL, pure x64 applicaitons.
Please click here for full description and original source code and binaries package of 32 bit version.
Installation
You need to put the driver file in your System32\Drivers folder. Make sure, if your using XP/2003 x64 Editions, to put the 64bit version there (hwinterfacedrvx64.sys) instead of the original 32bit version (hwinterface.sys)
Usage
There are examples and usage instructions for the 32bit version here . To use the pure 64bit version, all you need to do, is to link to my new InpOutx64.DLL using InpOutx64.lib. Everything else is the same.
Downloads
Driver source code (Requires the Windows 2003 DDK to build either 32bit or 64bit version)
32bit and 64bit Interface DLL source code (requires Visual Studio 2005 )
Just the binaries and libs requred to integrate with your own program.
Even though it is possible to get the parallel port base address from the properties dialogue, it will be much convenient, if we can retrieve the address of the available parallel ports programatically. DOS allowed applications to read information directly from BIOS. And that was the most popularly used method to identify parallel/Serial port address in DOS applications. But windows do not allow user mode applications to read BIOS directly. For a Windows application, this can be done with the help of a device driver only. The device driver can map the address in to the user mode process's address space and read the contents safely.
Logix4u introduces a library (hwinterface32) to access Physical memory directly from user mode application. Obviously, a device driver is involved in the process, but it is hidden from the user. Just like the Inpout32.dll , the device driver is embedded in the DLL and will be installed and configured automatically at the very first call made to the library (DLL). As a programmer, all that you need to do is, copy the DLL to relevant directory (system directory or application directory) and Call the exported functions. No driver installation, no hassles. Current Beta version of this library supports all the functions available in Inpout32.dll (Inp32() and Out32()), The library also contains functions Inpw32()/OutW32 which reads/writes 16 bit word and InpD32()/OutD32 which reads/writes 32 but DWords. Apart from I/O functions this library contains memory access functions also. Please refer the table below to see all functions supported by this library.
Function Description
short Inp32(short PortAddress) Reads a single Byte from the specified I/O address.
void Out32(short PortAddress, short data)
Writes a single Byte to the specified I/O address.
short InpW32(short PortAddress) Reads a Word from the specified I/O address.
void OutW32(short PortAddress, short data) Writes a Word to the specified I/O address.
long InpD32(short PortAddress) Reads a DWord from the specified I/O address.
void OutD32(short PortAddress, long data) Writes a DWord to the specified I/O address.
long ReadMemChar(ULONG Address) Reads a single Byte from the specified memory address.
long ReadMemShort(ULONG Address) Reads a 16 bit word from the specified memory address.
long ReadMemLong(ULONG Address) Reads a 32 bit Dword from the specified memory address.
void WriteMemChar(ULONG Address, UCHAR data ) Writes a single Byte to the specified memory address.
void WriteMemShort(ULONG Address, USHORT data) Writes a single Word to the specified memory address.
void WriteMemLong(ULONG Address, ULONG data) Writes a single DWord to the specified memory address.
Reading Parallel/Serial Port Address from BIOS
Typically, The addresses of Parallel and Serial ports present on a PC is stored in BIOS. An application can read this data to determine the presence of ports and there base addresses. The addresses of serial ports can be found starting from address 400H in BIOS. And the addresses of parallel port can be found starting from the address 408H in BIOS. The table below lists the BIOS address at which base address of each serial/parallel port can be found.
Address Port
400H Base I/O address for serial port 1 (COM 1)
402H Base I/O address for serial port 2 (COM 2)
404H Base I/O address for serial port 3 (COM 3)
406H Base I/O address for serial port 4 (COM 4)
408H Base I/O address for parallel port 1 (LPT 1)
40AH Base I/O address for parallel port 2 (LPT 2)
40CH Base I/O address for parallel port 3 (LPT 3)
It is easy to get the base address of Parallel/Serial port by reading the above addresses listed. The picture below shows the screen shot of a VB sample application which prints the base addresses of Parallel ports and serial ports with the help of hwinterface32 library.
To write an interfacing program with parallel port or serial port, we need to know the base address of the corresponding port in advance. Normally the base address of LPT1 will be 0x378 and that of LPT2 will be 0x3F8. And most of the home PCs will have only one parallel port with base address 0x378.
To write an interfacing program with parallel port or serial port, we need to know the base address of the corresponding port in advance. Normally the base address of LPT1 will be 0x378 and that of LPT2 will be 0x3F8. And most of the home PCs will have only one parallel port with base address 0x378. If only one port is present on the system we can probably assume that the base address is 0x378. And this can be confirmed by checking the Parallel Port properties in Device Manager. To do this, right click on My Computer, select Manage. Select Device Manager from the Computer Management console. Choose Parallel Port from the device tree, right click on it and select "Properties". Go to the "Resources" tab. Here you can find the Base address of the parallel port. A sample parallel port properties window is shown below. The Base address is highlighted in red circle.
Even though it is possible to get the parallel port base address from the properties dialogue, it will be much convenient, if we can retrieve the address of the available parallel ports programatically. DOS allowed applications to read information directly from BIOS. And that was the most popularly used method to identify parallel/Serial port address in DOS applications. But windows do not allow user mode applications to read BIOS directly. For a Windows application, this can be done with the help of a device driver only. The device driver can map the address in to the user mode process's address space and read the contents safely.
Logix4u introduces a library (hwinterface32) to access Physical memory directly from user mode application. Obviously, a device driver is involved in the process, but it is hidden from the user. Just like the Inpout32.dll , the device driver is embedded in the DLL and will be installed and configured automatically at the very first call made to the library (DLL). As a programmer, all that you need to do is, copy the DLL to relevant directory (system directory or application directory) and Call the exported functions. No driver installation, no hassles. Current Beta version of this library supports all the functions available in Inpout32.dll (Inp32() and Out32()), The library also contains functions Inpw32()/OutW32 which reads/writes 16 bit word and InpD32()/OutD32 which reads/writes 32 but DWords. Apart from I/O functions this library contains memory access functions also. Please refer the table below to see all functions supported by this library.
Function Description
short Inp32(short PortAddress) Reads a single Byte from the specified I/O address.
void Out32(short PortAddress, short data)
Writes a single Byte to the specified I/O address.
short InpW32(short PortAddress) Reads a Word from the specified I/O address.
void OutW32(short PortAddress, short data) Writes a Word to the specified I/O address.
long InpD32(short PortAddress) Reads a DWord from the specified I/O address.
void OutD32(short PortAddress, long data) Writes a DWord to the specified I/O address.
long ReadMemChar(ULONG Address) Reads a single Byte from the specified memory address.
long ReadMemShort(ULONG Address) Reads a 16 bit word from the specified memory address.
long ReadMemLong(ULONG Address) Reads a 32 bit Dword from the specified memory address.
void WriteMemChar(ULONG Address, UCHAR data ) Writes a single Byte to the specified memory address.
void WriteMemShort(ULONG Address, USHORT data) Writes a single Word to the specified memory address.
void WriteMemLong(ULONG Address, ULONG data) Writes a single DWord to the specified memory address.
Reading Parallel/Serial Port Address from BIOS
Typically, The addresses of Parallel and Serial ports present on a PC is stored in BIOS. An application can read this data to determine the presence of ports and there base addresses. The addresses of serial ports can be found starting from address 400H in BIOS. And the addresses of parallel port can be found starting from the address 408H in BIOS. The table below lists the BIOS address at which base address of each serial/parallel port can be found.
Address Port
400H Base I/O address for serial port 1 (COM 1)
402H Base I/O address for serial port 2 (COM 2)
404H Base I/O address for serial port 3 (COM 3)
406H Base I/O address for serial port 4 (COM 4)
408H Base I/O address for parallel port 1 (LPT 1)
40AH Base I/O address for parallel port 2 (LPT 2)
40CH Base I/O address for parallel port 3 (LPT 3)
It is easy to get the base address of Parallel/Serial port by reading the above addresses listed. The picture below shows the screen shot of a VB sample application which prints the base addresses of Parallel ports and serial ports with the help of hwinterface32 library.
To write an interfacing program with parallel port or serial port, we need to know the base address of the corresponding port in advance. Normally the base address of LPT1 will be 0x378 and that of LPT2 will be 0x3F8. And most of the home PCs will have only one parallel port with base address 0x378.
To write an interfacing program with parallel port or serial port, we need to know the base address of the corresponding port in advance. Normally the base address of LPT1 will be 0x378 and that of LPT2 will be 0x3F8. And most of the home PCs will have only one parallel port with base address 0x378. If only one port is present on the system we can probably assume that the base address is 0x378. And this can be confirmed by checking the Parallel Port properties in Device Manager. To do this, right click on My Computer, select Manage. Select Device Manager from the Computer Management console. Choose Parallel Port from the device tree, right click on it and select "Properties". Go to the "Resources" tab. Here you can find the Base address of the parallel port. A sample parallel port properties window is shown below. The Base address is highlighted in red circle.
Even though it is possible to get the parallel port base address from the properties dialogue, it will be much convenient, if we can retrieve the address of the available parallel ports programatically. DOS allowed applications to read information directly from BIOS. And that was the most popularly used method to identify parallel/Serial port address in DOS applications. But windows do not allow user mode applications to read BIOS directly. For a Windows application, this can be done with the help of a device driver only. The device driver can map the address in to the user mode process's address space and read the contents safely.
Logix4u introduces a library (hwinterface32) to access Physical memory directly from user mode application. Obviously, a device driver is involved in the process, but it is hidden from the user. Just like the Inpout32.dll , the device driver is embedded in the DLL and will be installed and configured automatically at the very first call made to the library (DLL). As a programmer, all that you need to do is, copy the DLL to relevant directory (system directory or application directory) and Call the exported functions. No driver installation, no hassles. Current Beta version of this library supports all the functions available in Inpout32.dll (Inp32() and Out32()), The library also contains functions Inpw32()/OutW32 which reads/writes 16 bit word and InpD32()/OutD32 which reads/writes 32 but DWords. Apart from I/O functions this library contains memory access functions also. Please refer the table below to see all functions supported by this library.
Function Description
short Inp32(short PortAddress) Reads a single Byte from the specified I/O address.
void Out32(short PortAddress, short data)
Writes a single Byte to the specified I/O address.
short InpW32(short PortAddress) Reads a Word from the specified I/O address.
void OutW32(short PortAddress, short data) Writes a Word to the specified I/O address.
long InpD32(short PortAddress) Reads a DWord from the specified I/O address.
void OutD32(short PortAddress, long data) Writes a DWord to the specified I/O address.
long ReadMemChar(ULONG Address) Reads a single Byte from the specified memory address.
long ReadMemShort(ULONG Address) Reads a 16 bit word from the specified memory address.
long ReadMemLong(ULONG Address) Reads a 32 bit Dword from the specified memory address.
void WriteMemChar(ULONG Address, UCHAR data ) Writes a single Byte to the specified memory address.
void WriteMemShort(ULONG Address, USHORT data) Writes a single Word to the specified memory address.
void WriteMemLong(ULONG Address, ULONG data) Writes a single DWord to the specified memory address.
Reading Parallel/Serial Port Address from BIOS
Typically, The addresses of Parallel and Serial ports present on a PC is stored in BIOS. An application can read this data to determine the presence of ports and there base addresses. The addresses of serial ports can be found starting from address 400H in BIOS. And the addresses of parallel port can be found starting from the address 408H in BIOS. The table below lists the BIOS address at which base address of each serial/parallel port can be found.
Address Port
400H Base I/O address for serial port 1 (COM 1)
402H Base I/O address for serial port 2 (COM 2)
404H Base I/O address for serial port 3 (COM 3)
406H Base I/O address for serial port 4 (COM 4)
408H Base I/O address for parallel port 1 (LPT 1)
40AH Base I/O address for parallel port 2 (LPT 2)
40CH Base I/O address for parallel port 3 (LPT 3)
It is easy to get the base address of Parallel/Serial port by reading the above addresses listed. The picture below shows the screen shot of a VB sample application which prints the base addresses of Parallel ports and serial ports with the help of hwinterface32 library.
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