LptPort

java.lang.Object
- ch.aplu.util.LptPort

```
public class LptPort
extends java.lang.Object
```
Support to write to and read from the LPT port registers on a Windows operating system. Uses the Java Native Interface (JNI) and INPOUT32.DLL by Jan Axelsons. Circumvents Windows protection of I/O-ports on W2K, XP, W2003 OS by installing a driver on the fly (when opening the port). INPOUT32.DLL and JLPTPORT.DLL needed in file system path (distributed with Examples, Chap. 34).

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`ACKNOWLEDGE` Bit value of Acknowledge line in status register of LPT port (at base address + 1).
`static int`	`AUTOLINEFEED` Bit value of Auto Linefeed line in control register of LPT port (at base address + 2).
`static int`	`BUSY` Bit value of Busy line in status register of LPT port (at base address + 1).
`static int`	`DATA0` Bit value of bit 0 in data register of LPT port (at base address).
`static int`	`DATA1` Bit value of bit 1 in data register of LPT port (at base address).
`static int`	`DATA2` Bit value of bit 2 in data register of LPT port (at base address).
`static int`	`DATA3` Bit value of bit 3 in data register of LPT port (at base address).
`static int`	`DATA4` Bit value of bit 4 in data register of LPT port (at base address).
`static int`	`DATA5` Bit value of bit 5 in data register of LPT port (at base address).
`static int`	`DATA6` Bit value of bit 6 in data register of LPT port (at base address).
`static int`	`DATA7` Bit value of bit 7 in data register of LPT port (at base address).
`static int`	`ERROR` Bit value of Error line in status register of LPT port (at base address + 1).
`static int`	`INITRESET` Bit value of Init/Reset line in control register of LPT port (at base address + 2).
`static int`	`PAPEREND` Bit value of Paper End line in status register of LPT port (at base address + 1).
`static int`	`SELECT` Bit value of Select line in status register of LPT port (at base address + 1).
`static int`	`SELECTIN` Bit value of Select In line in control register of LPT port (at base address + 2).
`static int`	`STROBE` Bit value of Strobe line in control register of LPT port (at base address + 2).

Constructor Summary

Constructors
Constructor and Description

LptPort()

Constructors
Constructor and Description
`LptPort()`

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`close()` Close port Do nothing, if port is not open.
`boolean`	`isOpen()` Return true if port is open, false otherwise.
`int`	`open(int address)` Open LPT port at specified base address, e.g. 0x378.
`int`	`readData()` Return content of data port (at base address) in lower byte.
`int`	`readStatus()` Return content of status port (at base address + 1) in lower byte.
`int`	`writeControl(int data)` Write lower byte of data into control port (at base address + 2).
`int`	`writeData(int data)` Write lower byte of data into data port (at base address).

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - DATA0
```
public static final int DATA0
```
    Bit value of bit 0 in data register of LPT port (at base address). Data may be written (to the external device) or read (from the external device).
    
    See Also:
    Constant Field Values
  - DATA1
```
public static final int DATA1
```
    Bit value of bit 1 in data register of LPT port (at base address). Data may be written (to the external device) or read (from the external device).
    
    See Also:
    Constant Field Values
  - DATA2
```
public static final int DATA2
```
    Bit value of bit 2 in data register of LPT port (at base address). Data may be written (to the external device) or read (from the external device).
    
    See Also:
    Constant Field Values
  - DATA3
```
public static final int DATA3
```
    Bit value of bit 3 in data register of LPT port (at base address). Data may be written (to the external device) or read (from the external device).
    
    See Also:
    Constant Field Values
  - DATA4
```
public static final int DATA4
```
    Bit value of bit 4 in data register of LPT port (at base address). Data may be written (to the external device) or read (from the external device).
    
    See Also:
    Constant Field Values
  - DATA5
```
public static final int DATA5
```
    Bit value of bit 5 in data register of LPT port (at base address). Data may be written (to the external device) or read (from the external device).
    
    See Also:
    Constant Field Values
  - DATA6
```
public static final int DATA6
```
    Bit value of bit 6 in data register of LPT port (at base address). Data may be written (to the external device) or read (from the external device).
    
    See Also:
    Constant Field Values
  - DATA7
```
public static final int DATA7
```
    Bit value of bit 7 in data register of LPT port (at base address). Data may be written (to the external device) or read (from the external device).
    
    See Also:
    Constant Field Values
  - ERROR
```
public static final int ERROR
```
    Bit value of Error line in status register of LPT port (at base address + 1). The external device informs the program about special conditions.
    
    See Also:
    Constant Field Values
  - SELECT
```
public static final int SELECT
```
    Bit value of Select line in status register of LPT port (at base address + 1). The external device informs the program about special conditions.
    
    See Also:
    Constant Field Values
  - PAPEREND
```
public static final int PAPEREND
```
    Bit value of Paper End line in status register of LPT port (at base address + 1). The external device informs the program about special conditions.
    
    See Also:
    Constant Field Values
  - ACKNOWLEDGE
```
public static final int ACKNOWLEDGE
```
    Bit value of Acknowledge line in status register of LPT port (at base address + 1). The external device informs the program about special conditions.
    
    See Also:
    Constant Field Values
  - BUSY
```
public static final int BUSY
```
    Bit value of Busy line in status register of LPT port (at base address + 1). The external device informs the program about special conditions.
    
    See Also:
    Constant Field Values
  - STROBE
```
public static final int STROBE
```
    Bit value of Strobe line in control register of LPT port (at base address + 2). The program sends some special commands to the external device.
    
    See Also:
    Constant Field Values
  - AUTOLINEFEED
```
public static final int AUTOLINEFEED
```
    Bit value of Auto Linefeed line in control register of LPT port (at base address + 2). The program sends some special commands to the external device.
    
    See Also:
    Constant Field Values
  - INITRESET
```
public static final int INITRESET
```
    Bit value of Init/Reset line in control register of LPT port (at base address + 2). The program sends some special commands to the external device.
    
    See Also:
    Constant Field Values
  - SELECTIN
```
public static final int SELECTIN
```
    Bit value of Select In line in control register of LPT port (at base address + 2). The program sends some special commands to the external device.
    
    See Also:
    Constant Field Values
- Constructor Detail
  - LptPort
```
public LptPort()
```
- Method Detail
  - open
```
public int open(int address)
```
    Open LPT port at specified base address, e.g. 0x378. Return 0 if successful, -1 otherwise.
  - isOpen
```
public boolean isOpen()
```
    Return true if port is open, false otherwise.
  - writeData
```
public int writeData(int data)
```
    Write lower byte of data into data port (at base address). Upper byte is ignored. Return -1 if port is not open, 0 otherwise
  - writeControl
```
public int writeControl(int data)
```
    Write lower byte of data into control port (at base address + 2). Upper byte is ignored. Return -1 if port is not open, 0 otherwise
  - readData
```
public int readData()
```
    Return content of data port (at base address) in lower byte. Upper byte is 0. Return -1 if port is not open.
  - readStatus
```
public int readStatus()
```
    Return content of status port (at base address + 1) in lower byte. Upper byte is 0. Return -1 if port is not open.
  - close
```
public void close()
```
    Close port Do nothing, if port is not open.

Class LptPort

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

DATA0

DATA1

DATA2

DATA3

DATA4

DATA5

DATA6

DATA7

ERROR

SELECT

PAPEREND

ACKNOWLEDGE

BUSY

STROBE

AUTOLINEFEED

INITRESET

SELECTIN

Constructor Detail

LptPort

Method Detail

open

isOpen

writeData

writeControl

readData

readStatus

close