barcode scanner vb.net textbox Copyright 2001 The McGraw-Hill Companies, Inc. Click Here for Terms of Use. in Software

Encoding Data Matrix in Software Copyright 2001 The McGraw-Hill Companies, Inc. Click Here for Terms of Use.

Copyright 2001 The McGraw-Hill Companies, Inc. Click Here for Terms of Use.
Data Matrix Decoder In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
ECC200 Drawer In None
Using Barcode generator for Software Control to generate, create Data Matrix image in Software applications.
460 COMPUTER CONTROL VIA PC PRINTER PORT
ECC200 Recognizer In None
Using Barcode recognizer for Software Control to read, scan read, scan image in Software applications.
Encoding DataMatrix In Visual C#
Using Barcode maker for Visual Studio .NET Control to generate, create Data Matrix image in .NET framework applications.
number of input-specific lines for directly communicating with a printer or other peripheral, though the number of input lines is small. This chapter deals primarily with how to use the parallel port on an IBM PC compatible. Why the PC It s a common computer hundreds of millions of them are in use today. While the PC comes in many styles, shapes, and sizes, they all do basically the same thing and provide the same specifications for both software and parallel port output. If you don t want to use your main PC for your robot work, you can probably find a secondhand machine for under $100.
Data Matrix Printer In Visual Studio .NET
Using Barcode generator for ASP.NET Control to generate, create Data Matrix image in ASP.NET applications.
Make ECC200 In Visual Studio .NET
Using Barcode printer for .NET framework Control to generate, create ECC200 image in .NET applications.
The text that follows pertains to the parallel port on an IBM PC compatible used in standard mode, and not in enhanced, bidirectional mode. On some computers, you may need to modify the system BIOS settings to turn off enhanced and/or bidirectional settings. Otherwise, the port may not behave the way you want it to. You can modify the BIOS settings by restarting your computer and following the Setup instructions shown on the screen as the PC boots.
Making Data Matrix ECC200 In Visual Basic .NET
Using Barcode drawer for VS .NET Control to generate, create Data Matrix image in .NET applications.
Code 39 Encoder In None
Using Barcode creator for Software Control to generate, create Code-39 image in Software applications.
The Fundamental Approach
ANSI/AIM Code 128 Maker In None
Using Barcode creation for Software Control to generate, create Code 128 Code Set C image in Software applications.
GTIN - 12 Generation In None
Using Barcode generator for Software Control to generate, create UCC - 12 image in Software applications.
In the original design of the IBM PC, system input and output such as the parallel port, serial port, and video display were handled by daughter boards that were plugged into the computer s main motherboard. This design practice continues, though today the average PC compatible comes with features such as parallel and serial port, video display, modem, and even a sound card already built into the motherboard. Whether these features are built into the motherboard or added by plugging in a daughter board, all of are input/output (I/O) ports of one type or another. The PC accesses its various I/O ports by using an address code. Each device or board in the computer has an address that is unique to itself, just as you have a home address that no one else in the world shares with you. Very old IBM PCs and compatibles used a monochrome display adapter board, which included its own parallel port. The printer port on this board used a starting address of 956. This address is in decimal, or base-10 numbering form. You may also see PC system addresses specified in hexadecimal, or base-16, form. In hex, the starting address is 3BCH (the address is really 3BC; the H means that the number is in hex). By convention, the parallel port contained on an I/O expansion board, or built into the motherboard, has a decimal address of 888 (or 378H hex) or 632 (278H). Parallel ports in the PC are given the logical names LPT1:, LPT2:, and LPT3:. Every time the system is powered up or reset, the ROM BIOS (Basic Input/Output System) chip on the computer motherboard automatically looks for parallel ports at these I/O addresses, 3BCH, 378H, and 278H, in that order. (It skips 3BCH if you don t have a monochrome card or printer port installed, which you probably don t unless your machine is ancient!). The logical names are assigned to these ports as they are found. Table 30.1 shows the port addresses for the parallel ports in the PC. Applications software often use the logical port names instead of the actual addresses, but in attaching a robot to the computer we ll need to rely on the actual address hence the need to go into these details.
UCC - 12 Printer In None
Using Barcode creation for Software Control to generate, create UCC - 12 image in Software applications.
Bar Code Maker In None
Using Barcode creation for Software Control to generate, create bar code image in Software applications.
THE FUNDAMENTAL APPROACH
Draw USD-3 In None
Using Barcode generation for Software Control to generate, create USD-3 image in Software applications.
1D Barcode Encoder In Visual Studio .NET
Using Barcode generation for Visual Studio .NET Control to generate, create Linear 1D Barcode image in .NET framework applications.
TABLE 30.1 ADAPTER
UCC - 12 Decoder In Java
Using Barcode decoder for Java Control to read, scan read, scan image in Java applications.
Draw UCC-128 In Objective-C
Using Barcode encoder for iPhone Control to generate, create GTIN - 128 image in iPhone applications.
ADDRESSES OF PARALLEL PORTS. DATA STATUS CONTROL
Print Data Matrix ECC200 In VB.NET
Using Barcode maker for VS .NET Control to generate, create DataMatrix image in VS .NET applications.
Draw Bar Code In Visual Basic .NET
Using Barcode maker for VS .NET Control to generate, create barcode image in VS .NET applications.
Parallel port on monochrome display card PC/XT/AT printer adapter Secondary LPTx card (as LPT2:) H Suffix Hex
Code 128 Maker In Java
Using Barcode maker for BIRT Control to generate, create Code 128 image in BIRT applications.
Code 128B Scanner In VB.NET
Using Barcode reader for .NET Control to read, scan read, scan image in .NET applications.
3BCH, 956D
3BDH, 957D
3BEH, 958D
378H, 888D 278H, 632D
379H, 889D 279H, 633D
37AH, 890D 27AH, 634D
D Suffix 5 Decimal
The PC parallel port is a 25-pin connector, which is referred to as a DB-25 connector. Cables and mating connectors are in abundant supply, which makes it easy for you to wire up your own peripherals. You can buy connectors that crimp onto 25-conductor ribbon cable or connectors that are designed for direct soldering. Fig. 30.1 shows the pinout designations for the connector (shown with the end of the connector facing you). Note that only a little more than half of the pins are in use. The others are either not connected inside the computer or are grounded to the chassis. Table 30.2 shows the meaning of the pins. Notice that not one address is given, but three. The so-called starting address is used for data output register. The data output register is comprised of eight binary weighted bits, something on the order of 01101000 (see Fig. 30.2). There are 256 possible combinations of the eight bits. In a printer application, this means that the computer can send specific code for up to 256 different characters. The data output pins are numbered 2 through 9. The bit positions and their weights are shown in Table 30.3. The other two registers of the parallel port, have different addresses (base address of the port, plus either one or two). These registers are for status and control. The most commonly used status and control bits (for a printing application, anyway) are shown in Fig. 30.3 on page 464. The function of the status and control bits is shown in Table 30.4 on page 465. To a printer, one of the most important control pins is pin number 1. This is the STROBE line, which is used to tell the peripheral (printer, robot) that the parallel data on lines 2 through 9 is ready to be read. The STROBE line is used because all the data may not arrive at their outputs at the same time. It is also used to signal a change in state. The output lines are latched, meaning that whatever data you place on them stays there until you change it or turn off the computer. During printing, the STROBE line toggles HIGH to LOW and then HIGH again. You don t have to use the STROBE line when commanding your robot, but it s a good idea if you do. Other control lines you may find on parallel printer ports include the following (some of these lines aren t always implemented):
Copyright © OnBarcode.com . All rights reserved.