110 lines
3.8 KiB
Plaintext
110 lines
3.8 KiB
Plaintext
AST RESEARCH TECHNICAL BULLETIN TB-0247 12-10-86
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SPERRY IT I/O PORT SELECTION FOR THE TURBOLASER
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Due to a slight incompatibility problem concerning the way the
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SPERRY IT configures its Serial and Parallel ports, a user must
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patch system memory for correct operation with the TURBOLASER
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printer.
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During a power on sequence, or a reboot of the computer, DOS
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examines the I/O port addresses to determine what Serial and
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Parallel ports are installed. DOS stores these addresses in
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memory locations as follows:
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SEGMENT:OFFSET I/O PORT ADDRESS
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40:00/01 COM1 03F8
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40:02/03 COM2 02F8
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40:08/09 LPT1 03BC
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40:0A/0B LPT2 0378
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40:0C/0D LPT3 0278
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TABLE 1: PORT ASSIGNMENT
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Assuming that all five ports are installed, memory locations would
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appear as follows if "DEBUG" DISPLAY (D) were used:
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DEBUG
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D40:00 F8 03 F8 02 00 00 00 00 -BC 03 78 03 78 02 00 00
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(COM1) (COM2) (LPT1) (LPT2) (LPT3)
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(The address bytes are stored in reverse order.)
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NOTE: On the SPERRY IT, these locations show all zeros and will
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inhibit correct TURBOLASER operation.
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When selecting printer ports, the user must know:
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1. What ports are installed and their I/O address.
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2. That no two devices can use the same I/O address.
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3. That DOS assigns both COM1 and LPT1 the hightest hexadecimal
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address it finds during the boot process. This can be very
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confusing.
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A. An example of the above procedure would assign Port address
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02F8 (normally COM2) as COM1 if Port address 03F8 was not
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also installed in the system.
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B. Another example would be if the only Parallel Port in the
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system has a I/O Port address of 0278 (normally LPT3).
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DOS would assign this port LPT1.
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C. Memory Location 40:00 through 40:0F would appear as:
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F8 02 00 00 00 00 00 00-78 02 00 00 00 00 00 00
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4. Most Multifunction "add-on" boards use I/O address 0378 as
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LPT1. This automatically bumps to LPT2 if another board, such
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as the IBM Monochrome adapter using address 03BC, is installed.
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5. The AST TURBOLASER port selection jumpers select the I/O Port
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addresses as shown in Table 1.
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6. There cannot be a COM2 Printer Port without a COM1.
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7. There cannot be a LPT2 without a LPT1, nor a LPT3 without having
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both a LPT1 and LPT2.
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PROCEDURE TO PATCH MEMORY
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1. Use EDLIN, or any other line editor, to create the two files
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listed below:
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PATCH (File Name)
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F 40:00 L2 F8 03 *if TurboLaser is COM1
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F 40:02 L2 F8 02 *if TurboLaser is COM2
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F 40:08 L2 BC 03 *if TurboLaser is LPT1
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F 40:0A L2 78 03 *if TurboLaser is LPT2
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F 40:0C L2 78 02 *if TurboLaser is LPT3
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Q (Quit)
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Note: Choose only one or two of the above ports according
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to the TURBOLASER jumper selections.
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SETPORT.BAT (File Name)
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DEBUG < PATCH
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*MODE COMn:9600,,,,P
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*MODE LPTn:=COMn
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*MODE LPTn:,,P
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*CD\ASTLP
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*LPLOAD PORTn ASTLASER.LNG
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*LPLOAD PORTn FBEGIN font font FEND
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or
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*EPSONI
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* Indicates optional entries depending on configuration
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and user application.
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2. The SETPORT.BAT file should be the last entry in the AUTOEXEC.BAT
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file if automatic execution is desired.
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3. The above two files should reside in the "ROOT" directory of the
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Boot disk, or a correct path should be specified.
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