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USERS MANUAL X.00 A Low Level Serial I/O Communications Driver for MS DOS and like Operating Systems. Copyright (c) 1993 by Raymond L. Gwinn 12469 Cavalier Drive Woodbridge, Virginia 22192 All Rights Reserved May 22, 1993 Fidonet address 1:265/104 (Routed mail only) Compuserve 72570,157 Internet 72570.157@Compuserve.com Data 703-494-0098 FAX 703-494-0595 i INTRODUCTION Previously, the documentation for X00 was little more than a collection of notes. The notes were added to as the development process continued and enhancements were made. I honestly did not suspect that X00 would become as widely used as it is. This manual is an attempt at some decent documentation for X00. But who do I document for? The user that is setting up a BBS just wants to get X00 installed and to move on to more important things. The user that is having problems needs information about serial I/O communications in general and the PC specifically. The application developer (programmer) needs detailed information about each individual function and the information generated. This manual is intended for the X00 user. A separate Application Programmers manual is being written. This manual and the software distributed with it is provided with no guarantees. Use at your own risk. ii TABLE OF CONTENTS WHAT IS X00 . . . . . . . . . . . . . . . . . . . . . . . . . 1 Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Licensing Information . . . . . . . . . . . . . . . . . . . . 2 Non-Commercial License . . . . . . . . . . . . . . . . . 2 Commercial License . . . . . . . . . . . . . . . . . . . 2 Commercial license fasttrack . . . . . . . . . . . . . . 4 GETTING STARTED . . . . . . . . . . . . . . . . . . . . . . . 5 Installing X00 . . . . . . . . . . . . . . . . . . . . . 5 Quick Start . . . . . . . . . . . . . . . . . . . . . . 5 OVERVIEW OF X00 USAGE . . . . . . . . . . . . . . . . . . . . 6 General Information . . . . . . . . . . . . . . . . . . 6 X00 loaded as a DOS Device Driver . . . . . . . . . 6 X00 loaded as a TSR . . . . . . . . . . . . . . . . 6 COMn and PORTn . . . . . . . . . . . . . . . . . . 6 COMMAND LINE OPTIONS . . . . . . . . . . . . . . . . . . . . 7 Specifying number of ports . . . . . . . . . . . . . . . 7 B option, Locking Baud, Data, Parity and Stop bits . . . 7 Valid locked baud rates . . . . . . . . . . . . . . . . 8 Eliminate . . . . . . . . . . . . . . . . . . . . . . . 8 Defer . . . . . . . . . . . . . . . . . . . . . . . . . 8 DV . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 FIFO . . . . . . . . . . . . . . . . . . . . . . . . . . 9 NOFIFO . . . . . . . . . . . . . . . . . . . . . . . . 10 NOPOST . . . . . . . . . . . . . . . . . . . . . . . . 10 R, Set Receive Buffer Size . . . . . . . . . . . . . . 10 T, Set Transmit Buffer Size . . . . . . . . . . . . . 11 VP or Master Interrupt Enable . . . . . . . . . . . . 11 Mapping port assignments . . . . . . . . . . . . . . . 11 Un-installing X00 . . . . . . . . . . . . . . . . . . 12 Multi-Tasking . . . . . . . . . . . . . . . . . . . . . . . 13 THE BIOS INT 14h EMULATOR . . . . . . . . . . . . . . . . . 15 IRQ SHARING . . . . . . . . . . . . . . . . . . . . . . . . 16 Appendix A, Hardware Port and IRQ Assignments . . . . . . . 17 Addresses and IRQs for COM1 and COM2 . . . . . . . . . 17 Defacto standard for COM3 and COM4 . . . . . . . . . . 17 Addresses and IRQ for COM3 through COM8 on the PS/2 . 17 Appendix B, SIO Chips . . . . . . . . . . . . . . . . . . . 18 8250 . . . . . . . . . . . . . . . . . . . . . . . . . 18 8250A . . . . . . . . . . . . . . . . . . . . . . . . 18 iii 16450 . . . . . . . . . . . . . . . . . . . . . . . . 19 16C451 . . . . . . . . . . . . . . . . . . . . . . . . 19 16550 Non A . . . . . . . . . . . . . . . . . . . . . 19 16550A . . . . . . . . . . . . . . . . . . . . . . . . 19 16550AF . . . . . . . . . . . . . . . . . . . . . . . 19 16550AFN . . . . . . . . . . . . . . . . . . . . . . . 19 16550s Made by Western Digital . . . . . . . . . . . . 20 16C551 . . . . . . . . . . . . . . . . . . . . . . . . 20 16C552 . . . . . . . . . . . . . . . . . . . . . . . . 20 82510 . . . . . . . . . . . . . . . . . . . . . . . . 20 Appendix C, Multi-Port Serial I/0 Cards . . . . . . . . . . 21 Connect-Com 4 . . . . . . . . . . . . . . . . . . . . 21 4 and 8 Port Boards from Decision-Computer . . . . . . 21 Stargate Plus 8 board from Software Link . . . . . . . 22 INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 1 WHAT IS X00 X00 is a Serial Input/Output (SIO) communications driver. It provides an interface between an application program and the serial communications hardware. X00 was originally designed as a FOSSIL driver. FOSSIL is an acronym containing the first character of several communications programs. The FOSSIL specification is basically an extension of the PC's BIOS services for serial communications. Except as noted in the Programmers Manual, X00 meets the FOSSIL level 5 specification. X00 provides additional functions that are not contained in the FOSSIL level 5 specification. X00 only works with 8250 (TYPE) serial I/O devices. Such devices include the 8250A, 16450, 16550, 16550A and the 82510. If you have a PC that is an IBM or near compatible which has a serial communication port, it is likely that it contains one of these devices. XU, a utility distributed with X00, will identify the existence of compatible SIO devices. Like other Device Drivers, X00 will do very little standing alone. There must be an application(s) program to use X00 before you will gain benefit. Since the introduction of the FOSSILs, a great number of new communications programs have come into existence. I like to think that the FOSSILs are largely responsible for this. Many programs that contain their own communications drivers have added FOSSIL support. One notable example is RBBS. Many programs written to use BIOS's serial communications services will also work with X00. This gives those programs the benefits of buffered interrupt driven I/O. Warranty There is none. Use at your own risk. 2 Licensing Information Non-Commercial License: A non-commercial license for use of X00 is included in the distribution file called LICENSE.TXT. Commercial License: Commercial Licenses will be liberally granted in return for a donation (usually tax deductible). Each commercial license will be individually granted. That is, there is no single policy that can be stated here. Some generally uniform commercial license policies follow (see next page for fasttrack licensing). 1 - X00 is usually licensed by product. 2 - All commercial licensees of X00 will receive a special copy of X00 that will identify, at boot time, the commercial product. 3 - I may require a fully licensed, fully featured, copy of your product for personal use on multiple computers. 4 - The required contribution, which is never to me personally, will usually be a one time contribution of $100.00. 5 - Proof of licensing belongs to you. That is, I am not going to be responsible for keeping records. I suggest that you keep a copy of the donation check so that you can send me a copy if a question arises. Otherwise you may have to make another contribution. 6 - You may only distribute versions of X00 that contain your product name in the X00 banner (at boot time). 7 - If you wish to have the latest version of X00 automatically sent to you with your product name in the X00 banner, then do the following: Send me a check for $10.00, in advance, along with a pre-addressed mailing label. If you require a 3.5 inch diskette, then write "3.5 inch" on the pre-addressed mailing label and send $15.00 (instead of $10.00). For updates, the check should be made out to Raymond L. Gwinn. The checks will be cashed when received. Individuals that wish to receive a mailed copy of the latest X00 version may also use this procedure. Once you have received an update, you will need to resend the update fee and pre-addressed mailing label if you desire to receive the next update. 8 - Your contribution check should state "X00 Licensing contribution" in the Memo or comment field. 3 If you write me about a commercial license (see next page), please include a voice phone number. Your chances of receiving a response are better if the voice phone number is included. Correspondence should be sent to: Raymond L. Gwinn 12469 Cavalier Drive Woodbridge, Va. 22192 Prior to making the special version of X00 available, I may wait for the check to clear the bank. If the check bounces, I will, most likely, not give any further consideration to a commercial license. 4 Commercial license fasttrack: Remember, in general, a commercial license is required only if you wish to distribute X00 with another software product. 1 - In a note or letter, give the name of the PRODUCT (not company) that X00 will be distributed with. If you wish to distribute X00 with multiple products, you will have to purchase an equal number of licenses. 2 - Make a check out to "Young Life" for $100.00 and send it to: Raymond L. Gwinn 12469 Cavalier Drive Woodbridge, Va. 22192 Consultants: The licensing fee to distribute X00 with software that you have written for a client is $1.00 per copy. The first 100 copies must be paid for in advance. That is, send a check as described in 2 above. Shareware: See 1 and 2 above. Remember, I do not make any money from X00. I get too many messages and letters for me to respond to. If you must ask questions (before you send a check) then you are probably not going to get an answer or license. 5 GETTING STARTED Installing X00 X00 is distributed as a ZIP file. To extract the individual files from the distribution file you need the program PKUNZIP or an equivalent. PKUNZIP is a product of PKWARE and can be downloaded from almost any bulletin board system (BBS). You probably already have PKUNZIP and know how to use it, otherwise I doubt that you would be reading this. When PKUNZIP is used to extract the various files, -AV should appear after each file name as it is extracted. In addition, the message: Authentic files Verified! should appear after the extraction process. If this message does not appear, or appears with a name other than Raymond L. Gwinn, the file is not an original X00 distribution file. The only file that the basic user actually needs is X00.SYS. Copy this file to a convenient directory or subdirectory on your system. I suggest that all users also install XU.EXE also. XU can provide important information about X00 that may be helpful when problems occur. Quick Start Copy X00.SYS and XU.EXE to the root directory of your boot drive or diskette. If you are going to use standard communications ports, either COM1 or COM2 on a PC or AT, or COM1 through COM8 on a PS/2, then add the following line to your CONFIG.SYS file: DEVICE=X00.SYS E If you wish to have more than one communications port active simultaneously, then modify the command line to include the number of simultaneously active ports you wish to support. For example, if you are using DESQview and you wish to run a BBS in two different windows, then add the following line to your CONFIG.SYS file: DEVICE=X00.SYS E 2 It should be noted that the above command tells X00 how many ports that are to be used simultaneously, not which ports. The application program may use ANY 2 serial ports in any order. If your setup is more complex, you must read on. 6 OVERVIEW OF X00 USAGE General Information Things can get a little confusing here. At the time of this writing, X00 is almost (if not completely) unique in its ability to function as a DOS device driver or as a Terminate (or Torment) and Stay Resident program (TSR). X00 loaded as a DOS Device Driver If X00 is to be used as a DOS device driver, it must be installed using the CONFIG.SYS file. For a precise description of the CONFIG.SYS file and its function, please refer to your DOS manual. Basically, you use a text editor to add a line to the CONFIG.SYS file. The line that you add is DEVICE=X00.SYS followed by optional parameters. The optional parameters will be described later. If X00.SYS is not in the current directory you will need to provide a DOS path to the directory containing X00. For example, if X00.SYS is in a subdirectory called COMM on the hard disk drive C, the line in the CONFIG.SYS file would be DEVICE=C:\COMM\X00.SYS. X00 loaded as a TSR If X00 is to be used as a Terminate and Stay Resident (TSR) program, then you must rename or copy X00.SYS to X00.EXE. The EXE version of X00 must be in the current directory or in a directory in the DOS path when it is executed. X00.EXE is executed like any other DOS program. That is, you type X00 at the DOS prompt followed by any optional parameters. In reality, you will probably be using a batch file to execute X00. COMn and PORTn X00 allows communications ports to be swapped around. That is, the serial port that DOS calls COM1 can be mapped (reassigned) to any X00 port. Therefore, when a reference in this document is made about PORTn, it refers to the serial I/O device that is mapped to that X00 port. When a reference is made to COM1 through COM8, it refers to the serial I/O device that DOS knows/uses as COMn. Also worth noting is that DOS numbers the serial I/0 devices starting at 1 (COM1 through COM8) and X00 numbers them starting at 0 (PORT0 through PORT7). X00's default is to assign PORT0 through PORT7 to COM1 through COM8. 7 COMMAND LINE OPTIONS The command line options are included in the command line that invokes X00. In several cases only the first 1 or 2 characters of the option need be entered. In other cases, the entire option name must be spelled out. Unless otherwise stated in the following descriptions, the entire option name must be spelled out. The parameters are given one after another on the same line and in any order. The length of the command line is limited only by DOS. Specifying number of ports If a single decimal number is in the X00 command line, it specifies the number of ports that X00 is to simultaneously support. The default is one port. The maximum value of the number of ports is 4 for non PS/2 systems and 8 for PS/2 systems. If you desire to use more than 4 ports on a non PS/2, each port address must be specified (see mapping port assignments below). Input and output buffers are allocated for each of the ports specified. Examples of usage are: When X00 is loaded as a Device Driver DEVICE=X00.SYS 3 DEVICE=X00.SYS 8 When X00 is loaded as a TSR X00 3 X00 8 B option, Locking Baud, Data, Parity and Stop bits Normally, the application program sets the baud rate and other parameters controlling the serial I/O hardware. Some modems provide better performance when the communications from the computer to modem is constant (Locked). That is, the computer to modem speed is not the same as the modem to modem speed. If this option is used, the modem must support RTS/CTS hardware handshaking and the feature must be enabled on the modem. The B command line option requires 2 parameters and allows an optional third parameter. The option is specified in the form B,PORTn,BAUD RATE,PARITY. You will most likely never want to lock the parity, data and stop bits. Examples of usage are: When X00 is loaded as a Device Driver DEVICE=X00.SYS B,0,2400 B,1,19200 or DEVICE=X00.SYS B,1,19200,8N1 When X00 is loaded as a TSR X00 B,0,2400 B,0,19200 or X00 B,1,19200,8N1 8 Valid locked baud rates are: 75, 110, 135.5, 150, 300, 600, 1200, 1800, 2000, 2400, 3600, 4800, 7200, 9600, 19200, 28800, 38400, 57600, and 115200. I can think of few conditions where it is necessary to use the optional third parameter of the B command line option. The optional third parameter is made up of 3 characters that specify the locked setting for data bits per character, parity bit and stop bit(s) in that order. The optional third parameter can be made up of any combination of the following first, second and third characters. First Second Third 5 N = None 1 6 E = Even 2 7 O = Odd 8 M = Mark (always 1) S = Space (always 0) The first character specifies the number of data bits per character, the second character specifies the handling of the parity bit and the third character specifies the number of stop bits. When 5 data bits and 2 stop bits (eg 5N2) are specified, the number of stop bits will actually be 1.5. As stated above, locking of the parity etc, is not advisable. Anytime an application program attempts to program the baud rate, parity etc, through X00, the locked values will be substituted. Eliminate Normally, when X00 is loaded a copyright notice is displayed for 5 seconds. Using the eliminate option will disable the 5 second display of the copyright notice. Only the first letter (E) is required to invoke this option. Examples of usage are: When X00 is loaded as a Device Driver: DEVICE=X00.SYS ELIMINATE or DEVICE=X00.SYS E When X00 is loaded as a TSR X00 ELIMINATE or X00 E Defer The Defer option creates problems on most systems. The Defer option should be avoided by most users. X00 must use several of the 80x86 interrupts. Normally, X00 will hook itself into the 80x86 interrupts when it is executed. The Defer option tells X00 9 to postpone hooking into some interrupts until an XU CAPTURE command is executed. If the defer option is used and a subsequent XU CAPTURE is not issued, X00 may not function correctly. Additionally, the XU CAPTURE must be executed prior to executing a multitasker like DESQview. Only the first 2 letters (DE) need to used to specify this option. Examples of usage are: When X00 is loaded as a Device Driver DEVICE=X00.SYS DEFER or DEVICE=X00.SYS DE When X00 is loaded as a TSR X00 DEFER or X00 DE The default for Defer is off. That is, X00 will by default immediately hook into all necessary 80x86 interrupt vectors. DV The DV command line option is only of interest to those using DESQview. The default for this option is off. When on (DV specified in the command line), X00 will make DESQview Pause calls when it seems that the application program is idle. This may make time available for other tasks to use. Refer to your DESQview manuals for details about the DESQview pause command. If you are using DESQview, try the DV option. If it does not adversely affect your system, leave it enabled (on). Examples of usage are: When X00 is loaded as a Device Driver DEVICE=X00.SYS DV When X00 is loaded as a TSR X00 DV FIFO Only the first letter of the command (F) is required to invoke this option. Some of the serial I/O hardware devices have First In First Out (FIFO) buffers. This command line option is used to specify the number of characters that X00 can load into the FIFO during a single transmit interrupt. In general this number should be set the size of the FIFO minus 1. For example, the popular 16550A has a 16 byte FIFO on both transmit and received data. Thus, if this option is used, I suggest the value of 15 be used for the 16550A. Examples of usage are: When X00 is loaded as a Device Driver DEVICE=X00.SYS FIFO=10 10 DEVICE=X00.SYS F=15 When X00 is loaded as a TSR X00 FIFO=15 X00 F=8 The size of the receive FIFO is always set to the maximum by X00. NOFIFO This command line option is used to completely disable the use of hardware FIFOs. Examples of usage are: When X00 is loaded as a Device Driver DEVICE=X00.SYS NOFIFO When X00 is loaded as a TSR X00 NOFIFO NOPOST Normally, when X00 is executed, it will alter the COM1 through COM4 hardware port addresses in BIOS RAM to match the addresses being used by X00. By doing so, many DOOR type programs that use INT 14h for their serial I/O will work correctly with X00 installed. This option (NOPOST) instructs X00 to leave the BIOS RAM unchanged. Examples of usage are: When X00 is loaded as a Device Driver DEVICE=X00.SYS NOPOST When X00 is loaded as a TSR X00 NOPOST R, Set Receive Buffer Size The R command line option allows the user to set the size of the receive buffer. The default size of the receive buffer is 512 bytes. The size of the buffer must be a power of 2. Valid buffer sizes are: 256, 512, 1024, 2048, 4096, 8192, 16384 and 32768. If an invalid buffer size is specified, the next lower correct buffer size is used. Many users needlessly set the size of the receive (or transmit) buffer too large. Examples of usage are: When X00 is loaded as a Device Driver DEVICE=X00.SYS R=1024 DEVICE=X00.SYS R=2048 11 When X00 is loaded as a TSR X00 R=1024 X00 R=2048 T, Set Transmit Buffer Size This option is identical to the R command line option (see above) except it sets the size of the transmit buffer. VP or Master Interrupt Enable VP stands for Vector Port which is not a very good name for the option. Some multiple port serial I/O cards default to only two ports enabled when power is turned on. A specified value must be written to an I/O port to enable the additional serial ports. Simply stated the VP command line option says to write the given value to the given port. Examples of usage are: When X00 is loaded as a Device Driver DEVICE=X00.SYS VP=03FF,80 When X00 is loaded as a TSR X00 VP=3FF,80 Both of the above examples in effect says, write the value 80 (hex) the I/O port at 3FF. Mapping port assignments This is the most complicated command line option for many users. By default, X00 maps up to 8 serial I/O ports (PORTS 0 through 7). X00 will (attempt to) determine the hardware architecture on which it is being executed. If a PS/2 is detected then the default Serial I/O port addresses will be set to match the PS/2 (see Appendix . If X00 detects that the system is not a PS/2 type system, then the default port addresses are as follows: 1 - Standard addresses for COM1 and COM2, 2 - The defacto standard for COM3 and COM4, and nothing for COM5 through COM8 (ports 4 through 7). Port mapping is necessary if your hardware configuration does not match the PS/2 or defacto standard for non PS/2 systems. COM1 and COM2 are the same for the PC, XT, AT and PS/2. However, hardware specifications for COM3 through COM8 became available only when IBM released the PS/2. Many multiple serial port cards are available for pre PS/2 systems that use a defacto standard. The most common assignments that I have seen for COM3 and COM4 are: COM3 at port address 3E8 12 using IRQ 3. COM4 at port address 2E8 using IRQ 4. Above the fourth port, I have not observed anything resembling a defacto standard. X00 will support almost any serial I/O card. However, in most cases, port mapping is required for anything beyond COM1 and COM2. Mapping port assignments uses two basic forms. They are: PORTn=COMn,IRQn PORTn=HEXADDRESS,IRQn Where: PORTn is the X00 port number and must be 0 through 7. COMn is a standard DOS port and must be COM1 through COM8. IRQn is the IRQ use by the serial port and must be IRQ0 through IRQ15. HEXADDRESS is a hexadecimal I/O port address that addresses the serial I/O device. In both basic forms, the IRQn is optional. X00 defaults all IRQn to IRQ3 except COM1 which defaults to IRQ4. Examples of usage are: When X00 is loaded as a Device Driver DEVICE=X00.SYS 0=COM4 DEVICE=X00.SYS 0=COM4,IRQ5 DEVICE=X00.SYS 0=2E8,IRQ3 DEVICE=X00.SYS 2=2E8 When X00 is loaded as a TSR X00 0=COM4 X00 0=COM4,IRQ5 X00 0=2E8,IRQ3 X00 2=2E8 Un-installing X00 When X00 is installed as a TSR, it can be un-installed by simply executing X00 with no command line parameters. If you wish to be sure that you do not accidently un-install X00, always execute it with a harmless parameter like X00 E. 13 Multi-Tasking By far, DESQview seems to be the multi-tasking software that X00 is most often used with. At the time of this writing, I personally use DESQview to run a multi line BBS. I believe it is best to load X00 before the multi-tasking program and to load it as a device driver. This enables all windows (tasks) access to X00. Loading X00 first also allows multiple windows to share the same IRQ. If you have loaded X00 prior to DESQview, you need to configure the window for no communications. That is, answer NO to the configuration questions, Uses Serial Ports and Optimize communications. I also suggest that you enable printer management within the window. Enabling printer management allows a remote drop to DOS to work on many systems. The Optimize communications option and the Printer management option are established with the DESQview SETUP program. The Uses serial ports (Y,N,1,2) option is in the "Change a Program" portion of window configuration. In several cases I have gained a significant increase in performance by turning X00 on prior to executing a program. Two notable cases are GATEWAY and DOORWAY. I used XU to turn X00 on. For example, XU PORT:n:ON just before invoking DOORWAY or GATEWAY produced significantly better input and output from the programs. Depending on your environment, an XU PORT:n:OFF may have to be issued after the program terminates. Also note that the n for PORTn is 1 less than the n in GATEn and COMn. The communications windows seem to work better if the ticks for the foreground and background are set relatively low. Most people that I have talked to use 2 ticks for both foreground and background. Only experimentation will determine the best setting for your system. If you do not wish to share an IRQ, you can load X00 as a TSR inside a DESQview window. When loaded inside a DESQview window, X00 is only available to programs in that window. X00 should be configured to support only 1 serial port and you should specifically name the port that X00 will use in the command line. For example use X00 0=COM1, instead of X00 1 or just plain X00. Identifying the specific serial port to be used in the window eliminates the chance that X00 will interfere with another active window. I strongly recommend that you use the 16550A (or later) SIO chip if you are using a multi-tasking system of any kind. 14 Most programs written to use BIOS INT 14h will work directly with X00's enhanced services. You should try turning X00 on using an XU PORT:n:ON command just prior to executing the program. Programs that do not have their own interrupt I/O will most likely give better performance. 15 THE BIOS INT 14h EMULATOR X00 is a BIOS INT 14h enhancement. So what is the need for a BIOS emulator also? Well, when X00 is turned off for a given port, it does not process the INT 14h functions using the enhanced code. Prior to the introduction of the BIOS INT 14h emulator, X00 simply passed calls to inactive serial ports to the BIOS INT 14h. Serial communications has changed considerably since the definition of the original BIOS for the PC. However, the BIOS services for serial communications have changed very little. Many program are still written to use the original BIOS serial communications services. Many older programs that use the BIOS communications services are still widely used. Problems occur when advanced high speed modems are used with these programs. Many of the programs are totally unaware of the concept of RTS/CTS handshaking that most of the high speed modems use. The programs cannot be aware that the user may have mapped the port addresses. BIOS for all systems (that I know of) support only 4 serial communications ports except PS/2 systems which support 8. I added the BIOS emulator to X00 to support many of the programs that are not (or cannot be) aware of the active communications environment. By default, X00's BIOS INT 14h emulator is enabled. It can be disabled by adding USEBIOS to the command line that invokes X00. When the emulator is enabled, port mapping, baud rate locking and hardware handshaking for the serial port(s) are maintained and 8 serial ports are supported. If the serial I/O chip is FIFOed, the emulator allows the FIFOs to be used. This means that many programs written to use BIOS can be used in the more advanced communications environments. The BIOS emulator can be activated and deactivated dynamically using XU. 16 IRQ SHARING Sharing the same IRQ for multiple communications ports is not for the weak of heart (or mind). Most popular multitasking software seems to do everything they can to prevent the sharing of a single IRQ between two or more tasks (windows). This big brother attitude of the multitaskers is cause of most of the problems in sharing a single IRQ between several serial communications ports. Several communications ports sharing a single IRQ is not too difficult to manage. The problem is the multitaskers not allowing the sharing of an IRQ by more than one task (window). In any case, version 1.20 of X00 has been tested with DESQview, RBBS and 8 comm ports sharing IRQ 3. I have also tested MultiLink with 2 comm ports sharing the same IRQ. With MultiLink, I had to use the NASTY option. Do not use the NASTY option with DESQview. The method I have developed to force sharing of an IRQ by multiple comm ports should work on most, if not all, multitaskers. It is too big a job, and too costly for me to test them all. Some general rules are as follows: 1 - X00 should be loaded before the multitasker. That is, if your multitasker allows the loading of device drivers into each window, DO NOT DO IT if you wish to share an IRQ. Load X00 at boot time and it should then be available to all tasks (windows). 2 - Two different boards (plugged into different slots) can not share the same IRQ. This is a hardware limitation and can not be corrected by software. This means that you can not plug in two internal modems, set them for the same IRQ and expect them to work. This does not apply to PS/2 systems. The problem of multiple boards sharing the same IRQ was corrected in the PS/2's buss design. 3 - When configuring the DESQview windows, we specified NO communications in the window. Remember, it is X00 (which is hopefully outside any window) that is doing the actual communications and not the application program inside the window. 4 - X00 can not (will not) share an IRQ with other software. If you attempt to run a program in a window that uses an IRQ that is being used by X00, the results are unpredictable. 5 - Do not load X00 into EMS memory. Loading high is okay. 17 Appendix A, Hardware Port and IRQ Assignments I have obtained the following information from various sources. Accuracy is not guaranteed. In fact, nothing in this document is guaranteed. Addresses and IRQs for COM1 and COM2 COM1 uses 03F8h and IRQ4 COM2 uses 02F8h and IRQ3 Defacto standard for COM3 and COM4 for PC, XT and AT COM3 uses 03E8h and IRQ4 COM4 uses 02E8h and IRQ3 Addresses and IRQ for COM3 through COM8 on the PS/2 COM3 uses 3220h and IRQ3 COM4 uses 3228h and IRQ3 COM5 uses 4220h and IRQ3 COM6 uses 4228h and IRQ3 COM7 uses 5220h and IRQ3 COM8 uses 5228h and IRQ3 All PCs prior to the PS/2 only used 12 bits to address hardware I/0 ports. Systems prior to the PS/2 and EISA can not address the standard addresses for COM3 through COM8. If an AT of below attempts to address COM3 through COM8 using the standard addresses, only the low 12 bits of the address are used. That is, the high digit of the hexadecimal address will be ignored. This means that any reference to COM3 through COM8 will actually address ports 220h through 22Fh. You should avoid expansion boards that use ports 220h through 22Fh unless the expansion board is a serial I/O board. X00 will (attempt to) determine the hardware architecture that it is being executed on and use to appropriate port addresses as defaults. 18 Appendix B, SIO Chips The following is a collection of comments developed from hearsay, random documents, experience, and technical specifications. So, take it with a grain of salt. Order information from the various manufactures if you want accurate information. A very good reference book that I use is available from National Semiconductor Corporation. It covers most of the SIO devices (also called UARTs) that you will find in all PCs and clones. The title of the book is Microcommunications Elements Databook. The publication number (manual number) is 400066. I am not sure that the book can be ordered directly from National semiconductor. They may require that you get it from a distributor. In any case, the address on the back of the manual is: National Semiconductor Corporation 2900 Semiconductor Drive P.O. Box 58090 Santa Clara, CA 95052-8090 Tel:(408)721-5000 TWX:(910)339-9240 8250 As best that I know, the 8250 was the first SIO chip (integrated circuit) that was used by the IBM PC and many clones. In my opinion, it was a poor choice on the part of IBM. I feel many superior devices, at comparable prices, were readily available. At that time, I feel the 8251A or the 8530 would have been better choices. I feel IBM used the 8250 to insure the PC would not have synchronous communications capability in a standard configuration. From a hardware standpoint the 8250 is a relatively slow device. It is advisable that programmers not perform successive inputs or outputs to this device. It seems that software programs can load the various registers of the 8250 faster than it can process the information. The 8250 had a total of 7 registers. The specifications state that 56kb is the maximum baud rate. 8250A I believe the 8250A is the 8250 with some bug fixes. I have no idea what the bugs may have been. A quick glance at the specifications shows the speed of the 8250 and 8250A to be much the same. The 8250A added an 8th register. This additional register enables software to detect if an 8250 is installed. The specifications state that 56kb is the maximum baud rate. 19 16450 The 16450 seems to be a speeded up version of the 8250A. There is no direct way (that I know of) for software to detect the difference between an 8250A and a 16450. I believe the 16450 was developed to eliminate the need for software to insert delays between successive accesses to the device. The specifications indicate the 16450 is a much faster device than its predecessors. The additional speed is only the speed at which the processor can access the device. The maximum baud rate for the 16450 is still stated at 56kb. However, I have been told by some people that they have run the 16450 successfully at much higher speeds. I do not believe there was ever a 16450A. 16C451 The 16C451 is a CMOS version of the 16450. CMOS is a term for the material and manufacturing process used to make the part. CMOS typically uses less power than other technologies. If you are not designing hardware, you should view the 16C451 as a 16450. 16550 Non A It is hard to find a 16550 (Non A). I was told by National Semiconductor that they did everything they could to get all 16550s back. X00 (and XU) will detect a 16550 and tell you if you have one. I am told that the 16550 was installed in early PS/2 systems. The 16550 was the first shot at a FIFOed version of the 8250 family from National semiconductor. However, I was told by National Semiconductor that the FIFOs of the 16550 are not reliable and they should not be enabled. X00 will treat a 16550 like a 16450. In this mode, they are reliable. National Semiconductor would not provide me with a specification for the 16550. However, I suspect its maximum baud rate is the same as the 16550A which is 256kb. 16550A, 16550AF and 16550AFN In the manuals that I have, National Semiconductor does not explain the differences between the 16550A and the 16550AF. I suspect the AF part may have a few bug fixes. I believe the N in AFN describes packaging, ceramic versus plastic, DIP versus surface mount etc. In the opinion of the author, there is no substitute for the 16550A (and its successors) in the 8250 type series. The 16550A is compatible with software written for the entire family of 8250 20 type devices. Programs that are 16550A aware can provide much improved performance over previous devices. The maximum baud rate for the 16550A is specified at 256kb. However, due to the hardware design of the PC et al, 115kb is the maximum baud rate that can be programmed. The 16550A can be plugged into the same socket that contains an 8250, 8250A or 16450. If your SIO expansion board has the SIO chips in sockets, you can upgrade to the 16550A by simply removing the old chips and replacing them with 16550As. The key to the performance increase of the 16550A is its FIFOs. It has 16 byte FIFOs for both transmit and receive data. 16550s Made by Western Digital I have been told, but I have not verified for myself, that 16550s made by Western Digital have a problem with their FIFOs when working at 2400 baud or below. 16C551 The 16C551 is a CMOS version of the 16550AF. See the above description of the 16C451 for a discussion of CMOS. Do not feel you need to upgrade from a 16550A or AF to a 16C551. There is no gain from an existing users point of view. 16C552 The 16C552 is two 16C551s on a single chip. These devices will start showing up on multi-port serial I/O cards. 82510 I believe Intel is the only company that manufactures the 82510. The 82510 is feature rich with several modes of operation. Its default mode is to operate as a 16450. The 82510 has a 4 byte FIFO for both transmit and receive data. A 4 byte FIFO is sufficient to provide significant performance over a basic 16450. The 82510 is small in size. Therefore, it is found in many lap tops. The 82510 is somewhat of a sleeper. I believe it would be much more widely used if Intel had promoted it more. However, given a choice between the 82510 and the 16550A, I would select the 16550A. 21 Appendix C, Multi-Port Serial I/0 Cards I get many requests for information about multi-port serial I/O card. I will describe the boards that I know about (or have heard about) here. I will add to the list as I receive precise information from users. My personal experience is with two boards that allow multiple serial I/O ports to share a single IRQ. The first board that I experimented with was the Connect-Com 4 from Software Link in Atlanta Georgia. The second board is the 4 PORT RS-232 CARD from Decision-Computer International in Taipei, Taiwan. Connect-Com 4 I found the manual for the Connect-Com 4 to be very confusing and their tech support even less helpful. I was able to get the board configured to use the standard COM1 and COM2 and the defacto standard for COM3 and COM4. If you use the Connect-Com 4, I suggest that you use it in this manner. This means that COM1 and COM3 will use IRQ4 and COM2 and COM4 will use IRQ3. The Connect-Com 4 has an 8 position DIP switch for configuration. The setting that I used was positions 2, 3, 7 and 8 ON (up), and all other positions OFF (down). In retrospect the Connect-Com 4 seems a bit expensive. However, once configured properly, the Connect-Com 4 worked without problem. Software Link can be reached in Atlanta Georgia at 404-448-5465. 4 and 8 Port Boards from Decision-Computer The second board that I have personally used, and the one that I am currently using is from Decision-Computer. The manual is written well enough that I did not need any technical support. There are two boards of interest from Decision-Computer, one is a 4 port serial I/O card and the other is an 8 port serial I/O card. I read somewhere in the documentation (which I can not find at this time) that the boards are a clone of boards available from AST. The boards from Decision-Computer are configured by jumpers. I use 4 ports of the 8 port card. I selected the (so called) Compatible Mode. This means that the first two serial I/O ports operate as standard COM1 and COM2 using IRQ4 and IRQ3 respectively. The jumper setting for Compatible Mode is clearly shown in the manual (page 8 of my manual). The I/O port addressed used in that mode are also clearly defined on the same page. A second jumper that must be set (JP2) defines the number of wait states. I set the jumper in position 3 which means 2 wait states. This was for a 20 mhz 386 system. This setting works fine for me. More wait states may be required or less may work 22 on your system. The amount of time lost due to wait states for serial I/O is very minimal. The last jumper(s) for the Decision-Computer 8 port RS-232 board is the selection of the IRQ(s) for ports other than the first 2. I selected IRQ3 for the additional ports that I am using (I am only using 4 of the 8). This means that the first port (COM1) is using IRQ4, all of the other (3) ports are using IRQ3. Position 2 of JP3 (left side) is the jumper that I installed. Stargate Plus 8 board from Software Link Dan Fox originally helped me with the testing of multiple serial I/O ports sharing a single IRQ. He informed me that the serial I/O board that he uses is a Stargate Plus 8 Board. He purchased the board from Software Link in Atlanta Georgia, 404-448-5465. Dan has all 8 ports using IRQ3. 23 INDEX 16450 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 16550 Non A . . . . . . . . . . . . . . . . . . . . . . . . . 19 16550A . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 16550AF . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 16550AFN . . . . . . . . . . . . . . . . . . . . . . . . . . 19 16550s Made by Western Digital . . . . . . . . . . . . . . . 20 16C451 . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 16C551 . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 16C552 . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 8250 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 8250A . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 82510 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Addresses and IRQ for COM3 through COM8 on the PS/2 . . . . . 17 Addresses and IRQs for COM1 and COM2 . . . . . . . . . . . . 17 Appendix A, Hardware Notes . . . . . . . . . . . . . . . . . 17 Appendix B, SIO Chips . . . . . . . . . . . . . . . . . . . . 18 Appendix C, Multi-Port Serial I/0 Cards . . . . . . . . . . . 21 B option, Locking Baud, Data, Parity and Stop bits . . . . . . 7 Baud rates . . . . . . . . . . . . . . . . . . . . . . . . . . 8 BIOS RAM . . . . . . . . . . . . . . . . . . . . . . . . . . 10 CAPTURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 COMn and PORTn . . . . . . . . . . . . . . . . . . . . . . . . 6 CONFIG.SYS . . . . . . . . . . . . . . . . . . . . . . . . 5, 6 Defacto standard for COM3 and COM4 . . . . . . . 11, 12, 17, 21 Defer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 DESQview . . . . . . . . . . . . . . . . . . . . . 5, 9, 13, 16 DV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Eliminate . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 FIFO . . . . . . . . . . . . . . . . . . . . . 9, 10, 15, 19, 20 FOSSIL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 GETTING STARTED . . . . . . . . . . . . . . . . . . . . . . . . 5 IRQ SHARING . . . . . . . . . . . . . . . . . . . . . . . . . 16 Licensing Information . . . . . . . . . . . . . . . . . . . . . 2 Commercial License . . . . . . . . . . . . . . . . . . . . 2 Commercial license fasttrack . . . . . . . . . . . . . . . 4 Non-Commercial License . . . . . . . . . . . . . . . . . . 2 Locked . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Locking . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Baud . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Data . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Parity and Stop bits . . . . . . . . . . . . . . . . . . . 7 Valid locked baud rates . . . . . . . . . . . . . . . . . 8 Mapping port assignments . . . . . . . . . . . . . . . . . . 11 Multi-Tasking . . . . . . . . . . . . . . . . . . . . . . . . 13 NOFIFO . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 NOPOST . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Number of data bits . . . . . . . . . . . . . . . . . . . . . . 8 Number of stop bits . . . . . . . . . . . . . . . . . . . . . . 8 Parity bit . . . . . . . . . . . . . . . . . . . . . . . . . . 8 PKUNZIP . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 24 Authentic files . . . . . . . . . . . . . . . . . . . . . 5 Port assignments . . . . . . . . . . . . . . . . . . . . . . 11 Quick Start . . . . . . . . . . . . . . . . . . . . . . . . . . 5 R, Set Receive Buffer Size . . . . . . . . . . . . . . . . . 10 RBBS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 SIO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 SIO Chips . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Specifying number of ports . . . . . . . . . . . . . . . . . . 7 T, Set Transmit Buffer Size . . . . . . . . . . . . . . . . . 11 Terminate and Stay Resident . . . . . . . . . . . . . . . . . . 6 THE BIOS INT 14h EMULATOR . . . . . . . . . . . . . . . . . . 15 TSR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Uninstalling X00 . . . . . . . . . . . . . . . . . . . . . . 12 VP or Master Interrupt Enable . . . . . . . . . . . . . . . . 11 Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 WHAT IS X00 . . . . . . . . . . . . . . . . . . . . . . . . . . 1