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QBserial version 2.10 Serial I/O Routines for use with QuickBASIC & BC6/7 This library will provide you with serial I/O communications routines for use in QuickBASIC 4.x (with or without PDQ), and the Microsoft Basic Compiler 7.x Professional Development System. No longer are you forced to use the poor communications support provided by QB. This program will allow you to control 8250 (includes 16450) type communications ports at speeds of up to 115200 baud. Communication ports 1 - 4, and non-standard addresses are supported. You will no longer have problems with the DTR signal. DTR is left in the same state it was in when before you called this driver, or it can be controlled by your program. The serial driver includes XON/XOFF and CTS/RTS handshaking. Serial input is interrupt driven, using any IRQ you specify (1 - 7), with incoming XOFF flow control (if enabled), or RTS flow control (if enabled) to prevent overrunning the input buffer. These are the same serial I/O routines used in Sparkware's Qmail door, and the User Database System Doors "Query Door" and "Upload Door". The driver was written with Microsoft's C, and compiled with version 6.0a of that compiler. This driver is useable with QuickBASIC version 4.x, and Basic Compiler 6.x & 7.x PDS. (With or without PDQ). BC 1.x, QuickBASIC 2.x, and 3.x are not supported by this driver. The reason is that versions of QuickBASIC prior to 4.0 do not support the extensive multi-language interface that QB4.x has (via the DECLARE statement and Microsoft language extensions). Throughout this manual QB will be used to refer to both QuickBASIC and the Basic Compilers (6.x & 7.x PDS). Before the driver can be used, the following DECLARE statements must be added to the beginning of your QB program: DECLARE SUB OpenComm CDECL ALIAS "_open_comm" (BYVAL Port%, BYVAL_ IRQ%, BYVAL Wlen%, BYVAL Parity%, BYVAL Baud&, BYVAL HS%) DECLARE SUB CloseComm CDECL ALIAS "_close_comm" () DECLARE FUNCTION WriteChar% CDECL (BYVAL Ascii%) DECLARE FUNCTION ReadChar% CDECL () DECLARE SUB Transmit CDECL ALIAS "_transmit_string" (addr$) DECLARE FUNCTION DataWaiting% CDECL ALIAS "_data_waiting" () DECLARE SUB ClearInputBuffer CDECL ALIAS "_clear_input_buffer" () DECLARE SUB CarrierDetect CDECL ALIAS "_carrier_detect_flag"_ (BYVAL OnOff%) DECLARE FUNCTION CarrierLost% CDECL ALIAS "_carrier_state" () DECLARE SUB DTRcontrol CDECL ALIAS "_dtr" (BYVAL OnOff%) DECLARE SUB RTScontrol CDECL ALIAS "_rts" (BYVAL OnOff%) DECLARE FUNCTION DriverCopyright% CDECL () QBSERIAL User Manual - V 2.10 Page 1 These declarations specify all the entry points into the serial driver, They are in the include file QBSERIAL.DEC. DO NOT change them or the driver may not function. Refer to the included sample programs SIMPLE.BAS & PCBDOOR.BAS, they use most of the calls described below. Port Initialization OpenComm Port%, IRQ%, Wordlen%, Parity%, Baudrate&, HS% Port% This is an integer value. If the specified port is 1 to 4, the driver opens that port. If you specify the port as ZERO (0) the driver enters "LOCAL" mode. This allows you to call the driver with data, but the driver won't send anything. This is useful when working with "doors". if you specify the port as any other value, QBserial will use that as the base address for the port. This allows you to work with non-standard I/O addresses. Note however that if you open a non-standard port, you must specify an IRQ value of 1 to 7 IRQ% Specifies which interrupt to use with this port. If the value of IRQ% is ZERO (0), then the default IRQ values are used (COM1 & COM3 use IRQ4, COM2 & COM4 use IRQ3). This is what most applications will use. Specify an IRQ value of 1 through 7 when you want to use an IRQ value other than the default. Such as when you want to use IRQ7 with COM3. NOTE: Be careful when choosing an IRQ value other than the default. Most machines use the other IRQ inputs for other machine functions such as the Hard drive and system clock. QBserial DOES NOT chain the interrupt, it takes it over entirely. If you choose an IRQ that is used for something already, your machine will most certainly operate improperly. Wordlen% an integer specifying the word length of the serial data. It has a value of 7 or 8. Parity% an integer, 0 = NONE, 1 = ODD, 2 = EVEN. BaudRate& is a LONG INTEGER representing the desired baud rate. Valid numbers are 0, 300, 1200, 2400, 4800, 9600, 19200, 38400, 57600, and 115200. The value you send is NOT checked and I assume you could generate crazy baud rates if desired. 115200 is the absolute maximum rate that can be generated. If you specify a baud rate of ZERO then the serial port is used AS-IS. The rate, word length, & parity are NOT changed. This is useful for door operation QBSERIAL User Manual - V 2.10 Page 2 since the port is already initialized at the proper settings when you get control. HS% an integer specifying the type of handshake you wish to use between the CPU and Modem (or destination device). Valid numbers are: 0 = NO handshake, 1 = XON/XOFF, 2 = CTS/RTS, 3 = XON/XOFF and CTS/RTS. Serial Output To send a string of data out the serial port, you use the "Transmit" call as follows: Temp$ = "Transmit this..." Transmit Temp$ or Transmit "Send this also...." If you want to transmit single characters, you can use the "WriteChar" function. Transmit calls WriteChar to send the actual characters to the port. If you wish to use WriteChar, it has the following format: Status% = WriteChar(Char%) Char% is the integer value of the character you want to send, it is not a string. Status% is an integer returned by WriteChar, it is NON-ZERO if the character was actually sent to the port, and ZERO if the character was not sent. WriteChar will loop indefinitely on CTS hold, XOFF hold, or Transmit Buffer Busy. These loops will exit if carrier is lost in FULL or PARTIAL modes and return a ZERO status%. WriteChar gives you more low level control of the sending of characters, but you must send each character separately and monitor its status. The Transmit function monitors the status of its calls to WriteChar and triggers QuickBASIC's User Event trap (UEVENT) if a carrier loss occurs in FULL mode. The UEVENT trap (FULL mode) is used by default. You can disable the use of this event trap in the event you already use the UEVENT trap for something else (PARTIAL mode). Therefore, by default, carrier loss detection in your program is done with the ON UEVENT GOSUB/UEVENT ON statements. The example programs show the use of this method. By default UEVENT is also used for catching carrier loss on keyboard input. this is described below. QBSERIAL User Manual - V 2.10 Page 3 Serial Input Serial input is managed with three functions: DataWaiting, ReadChar, & ClearInputBuffer. DataWaiting is used to test the input buffer to see if any characters need to be read from it. ReadChar is then called to get the characters. ClearInputBuffer flushes the input buffer of any existing characters. Both example programs contain a subroutine called "KeyboardInput" that demonstrates the use of these calls. It also properly handles input from the local and remote keyboards, and can be the routine you use in your programs if you wish. Basically the procedure for reading the remote keyboard (serial input) is as follows: IF DataWaiting THEN C$ = CHR$(ReadChar) END IF The DataWaiting function also monitors the state of the carrier detect signal and triggers, in FULL mode, the user event trap (UEVENT) if carrier is lost. As you can see a singular trap routine catches carrier loss on output as well as input. You will notice that the "KeyboardInput" subroutine loops using DataWaiting, and as such, carrier is constantly checked while waiting for input. If the ReadChar function is called when no data is available (as indicated by DataWaiting) a NULL character is returned. If XOFF/XON, CTS/RTS, or BOTH is enabled, then the serial buffer will be protected from overfills. When the buffer reaches 75% of capacity, an XOFF will be sent on the serial output or RTS will be dropped. When the buffer empties out to 25% of capacity, an XON will be sent or RTS raised. The capacity of the input buffer is 2048 bytes. Carrier Detect Control There are three modes of carrier detection: Full, Partial, & None. Each has it own distinct use for a particular purpose. The driver defaults to FULL carrier detection unless you change it. The following call is used to change control modes: CarrierDetect 0 [or] 1 [or] 2 Specifying a TWO (2) sets carrier detection to FULL. This is the default mode. When a loss of carrier occurs while transmitting, polling for input data, or sitting in a wait loop (XOFF/XON or CTS), the driver will return to the calling program and trip the UEVENT flag. Tripping the UEVENT flag causes Basic to go to the User Event trap routine (providing ON UEVENT GOSUB/UEVENT ON has been set up in the user program). You should use this mode only if you want to use the UEVENT trap for carrier loss detection. You cannot transmit data (with the Transmit function) in this mode if QBSERIAL User Manual - V 2.10 Page 4 there is no carrier. You can send characters in this mode with the WriteChar function. Specifying a ONE (1) sets carrier detection to PARTIAL. This mode is similar to FULL with the exception that the UEVENT flag is not tripped when carrier is lost. This mode should be used if UEVENT is used for something else in your program, or you don't wish to utilize UEVENT. Specifying a ZERO (0) sets carrier detection to NONE. An example of this mode would be where "plain Jane" serial I/O is required (such as communicating with a "dumb" terminal). In this application there are no modem handshake signals (3 wire EIA/RS-232). This mode can also be used for talking to a modem when there is no carrier signal present (such as dialing and initialization commands). The Transmit and WriteChar routines will always transmit data in this mode with or without carrier present. Carrier detection must be disabled in this mode to prevent calls to Uevent and disable the no carrier escape mechanisms built into the XON/XOFF loops. Important: if you are using the XOFF/XON protocol in this mode and receive an XOFF while transmitting, you will sit forever waiting for an XON. This is a normal condition, with the exception that there is no escape from this loop other than XON. Please note that there was an error in documentation in the previous version (2.0). With CarrierDetect set to 1 (partial) data WOULD NOT be sent if no carrier was present (I had said it would be sent). You MUST use mode 0 if you wish to converse with a modem that is not currently on-line (has no carrier). Once carrier is detected, you would then switch to either mode 1 or 2. Carrier Loss Detection by Polling As mentioned above, by default, the UEVENT trap is used to detect when a loss of carrier occurs. There is also a function that allows you to detect loss of carrier without using the UEVENT trap. While I feel that using UEVENT is the simplest way to catch a carrier loss in a program, it is possible that UEVENT might need to be used by something else. This function is: X% = CarrierLost This function call allows to you to 'poll' for the state of carrier. CarrierLost returns a NON-ZERO value when there is NO carrier, and a ZERO when there IS carrier. CarrierLost is a real time function, it returns the current carrier condition at the time of the call. This allows you to code simple IF or DO loops to detect loss: IF CarrierLost THEN ..process carrier loss END IF QBSERIAL User Manual - V 2.10 Page 5 Program Termination Since "OpenComm" seizes an interrupt vector, this vector needs to be restored BEFORE your program ends. If you neglect to restore this vector, you could be risking a crash. The routine used to reset the vector is: CloseComm. Only use CloseComm if you specified a port value of 1, 2, 3, 4, or a non-standard port address in the OpenComm call. If you specified a port value of ZERO (Local mode) the interrupt vector is NOT grabbed, and does not need to be reset. CloseComm also resets any UART registers to their original value. Data Terminal Ready (DTR) Everybody that has used QuickBASIC's OPEN COMn statement is very familiar with the problems of the DTR signal. Apparently Microsoft felt that DTR would never be needed after a program terminates. Anybody who has ever tried to write a door, or chain from one program to another has cursed this decision at some time during their programs development. This driver handles the DTR with a different view. When you close the comm channel the DTR signal is left in the same state it was when you opened the comm channel. For door applications, this is a must. A function call is provided however that allows your program to control the DTR signal: DTRcontrol 1 [or] 0 ' 0 = DTR OFF, 1 = DTR ON Additionally when you use DTRcontrol to change the state of the DTR signal it also instructs the driver to leave it this way when the CloseComm function is called. Remember that the driver leaves DTR the way it found it when OpenComm was called. If you used some other method to change DTR after OpenComm was called, it would automatically return to that original state when you called CloseComm. Therefor only DTRcontrol should be used if you wish to change the state of DTR. Request To Send (RTS) Request To Send (RTS) is a hardware flow control signal used to tell the remote device to STOP sending data to us. Normally RTS is set "on" and data will always flow (or the signal is ignored at the remote end). With some communications programs RTS is used to temporarily stop a modem from sending data while I/O is done to a slow disk. This is especially true with high speed communications where there is very little time between interrupts. This function is independent of the automatic RTS flow control selected by handshake 2 or 3 which tells the remote device to stop sending when QBSERIAL User Manual - V 2.10 Page 6 the input buffer is almost full. This function allows you to manually control the state of RTS so you could, for instance, go off and write the data somewhere without fear of loosing data. RTScontrol 1 [or] 0 ' 0 = RTS OFF, 1 = RTS ON When you use RTScontrol to change the state of the RTS signal it also instructs the driver to leave it this way when the CloseComm function is called. The driver leaves RTS the way it found it when OpenComm was called. If you used some other method to change RTS after OpenComm was called, it will automatically return to that original state when you call CloseComm. Therefor only RTScontrol should be used if you wish to change the state of RTS. This is similar in the way DTRcontrol works. Driver Version and Copyright A function is available to access the drivers version and copyright string. This would be used if you wish to display in your final product the version of QBserial that your are using, and/or my copyright along with yours. In order to access the copyright string, the following lines should be added to your Basic program: X& = DriverCopyright WHILE (PEEK(X&)) CP$ = CP$ + CHR$(PEEK(X&)) X& = X& + 1 WEND This places the version/copyright string into string variable CP$. This string may now be handled in whatever method you choose. Cresent's PDQ Library An object module for use with PDQ is also included. PDQ does not support UEVENT, so all references to UEVENT in the text should be ignored. You will need to do carrier checking by polling with the CarrierLost function. If you use FULL mode and carrier is lost it will operate the same way as PARTIAL mode. The only exception to this is the Transmit function, which when in FULL mode, will not transmit data. NOTE: An additional note for PDQ users. Since PDQ replaces the Microsoft run time libraries, the public variable ACRTUSED is not satisfied during the link stage. A dummy stub file, ACRTUSED.OBJ is included with QBserial to prevent this error from occurring. The next paragraph explains the proper linking sequence. QBSERIAL User Manual - V 2.10 Page 7 Linking Since object modules are provided for QB4.x, BC7, and PDQ, you will need to select which one to use for your program. The file QBSER.OBJ should be used for programs compiled with QuickBASIC, BC7SER.OBJ is to be used for programs compiled with BC7 PDS, and QBSERPDQ.OBJ is for PDQ users. Typical link command lines would look like this: (Please note that your command lines will probably be different if you use additional libraries to generate your code) Link yourprog qbser; (For QuickBASIC) Link yourprog bc7ser; (For BC7 PDS) Link yourprog qbserpdq acrtused; (For PDQ) Quick Libraries If you wish to develop programs from within the environment, you will first need to create a Quick library using one of the object modules QBSER.OBJ, BC7SER.OBJ, or QBSERPDQ.OBJ. To create a Quick lib for QuickBASIC 4.x, use the following Link command: Link QBSER,,,BQLB4x/q Where "BQLB4x" is one of the following: BQLB40.LIB, BQLB41.LIB, or BQLB45.LIB. Use the one that came with your compiler. If you use the wrong BQLB file you might get an "Invalid Format" error when attempting to start QuickBASIC. QBSER.OBJ may also be added to Quick Libraries containing other routines and OBJ's as well. To create a Quick Library for use within QBX (BC7's environment) use the following link command (be sure to use Link v5.xx that came with BC7): Link BC7SER,,,QBXQLB/q; For PDQ, use the method for QB4.x, since you will be using the built in run time routines built into the environment. You ONLY use QBSERPDQ.OBJ when you link the EXEcutable file. Remember too, that you can also add BC7SER.OBJ to Quicklibs containing other routines. QBSERIAL User Manual - V 2.10 Page 8 Specifications The following port addresses and default interrupts are used: Comm Base Address IRQ (Default) 1 3F8 hex 4 2 2F8 hex 3 3 3E8 hex 4 4 2E8 hex 3 Please read the section explaining the OpenComm function for information on how to use addresses or IRQ's other than the defaults. QBSERIAL User Manual - V 2.10 Page 9 Registration and Support QBserial is distributed as shareware. You may copy and distribute it freely. QBserial is not free software, and requires registration. There are two classes of registration which are dependant upon use: Commercial and Non-Commercial. Registration of QBserial is $25 for non-commercial use. Non- commercial uses are: Personal use, or use in another shareware product such as doors and utilities where you allows others to try the product first before buying and request a nominal registration fee. Source code is available as an option for an additional $50. Registration of QBserial for commercial use is $75. Commercial uses are: Inclusion of QBserial into ANY product that is to be sold for profit, or any use of this program in a business environment. Any program that must be paid for in advance before the product is delivered, or use in a corporate environment fits this category. Commercial registration includes the source code for QBserial in C (Microsoft C), if desired. Please register your copy! Software and Shareware distribution houses may charge a nominal distribution and copying fee not to exceed $5.00. They may not sell this program outright or ask you for the registration fee directly, they must inform you that registration is required by the author. If you have access to a BBS that is an ILINK mail network member, you can reach me in the Basic conference. If you do not have ILINK access anywhere nearby, then you can always contact me on the SailBoard BBS at the number listed below. I would prefer if you contact me directly on the SailBoard however, as ILINK isn't as reliable as Id like, and I have missed messages. I'll do the best I can to help if you have questions. Bugs will be tended to if required, and good suggestions tend to be implemented. Source Code The source code for QBserial is available. The source is available by signing at the appropriate place on the registration form. The source may be used for you own internal uses only. The source may not be distributed by you to any other person, even if you make changes to it. Nor can the resulting object code be sold or QBSERIAL User Manual - V 2.10 Page 10 distributed. Modifications can only be used in your end product, and without any type of royalty. The source is available only after you register QBserial. The license fee for the QBserial source code is $50.00 for Non-Commercial users. Commercial users receive the source as part of their registration fee if they desire it. Jeff Sumberg Sysop(2) - SailBoard BBS Wayne, NJ, 201-831-8152 [ or ] Box 212 Ringwood, NJ, 07456 Acknowledgments Thanks go out to Mark "Sparky" Herring for using these routines in his highly successful Qmail door (versions 3 & 4). Thanks to Mark Wilson for some very good ideas in version 2.0. Thanks to Michael Conley for finding a real time sensitive interrupt problem. Thanks to Jeffrey Morley (author of ZipLab) for testing. Changes and Revisions 06/09/89 1.0 Initial Release 06/21/89 1.1 Added carrier detection control. Calling program can turn detection off and on as desired. Necessary if data sending/receiving required if carrier isn't present. 09/01/89 1.2 Fixed a bug in Readchar where 'extended' characters (ASCII 128 to 255) were causing an Illegal Function Call in the CHR$() conversion (because they were being returned as negative numbers). Extended character may now be received properly. Added three new functions: CDtrap, CarrierLost, and DTRcontrol. 03/24/90 1.5 Added support for Basic Compiler 7.0 PDS and PDQ. Added sections to manual about Linking, Source code availability, and updated section on Quicklibs. Separate object files now supplied for QB, BC7, and PDQ. QBSERIAL User Manual - V 2.10 Page 11 05/01/90 1.6 Oops! PDQ users found out fast that I forgot to compile the PDQ module with stack checking removed. I also forgot to include ACRTUSED.OBJ to satisfy linking requirements. Sorry 'bout that! Released only as beta to those that needed it. 11/01/90 2.0 Added capability to specify non-standard port addresses and which IRQ to use when the port is opened. Removed CDtrap function. Created new carrier detection modes using the CarrierDetect function. (0 = NONE, 1 = PARTIAL, 2 = FULL). Also added DriverCopyright function to allow program access to the driver version. 02/08/92 2.10 Added RTS flow control support. RTS will be used to control data coming in to QBserial when the handshake is set to 2 (CTS/RTS). Removed necessity for SERIAL.LIB library file by adding inline assembler that performed the routines that were previously included in that library. QBserial is now compiled with Microsoft C 6.0 which will give smaller, faster, and more efficient code than QuickC could generate. This is especially true in the interrupt area. Added new function RTScontrol, to allow program to control RTS line directly. Increased size of input buffer from 1024 to 2048 bytes. Changed method in which interrupt controller mask bits were set & cleared. Corrected error found in documentation describing the function of CarrierDetect. Future Plans I hope in the not to near future to be able to add support for extended interrupts (IRQs 8-15). There have been several requests for this already. I also hope to be able to add support for the 16550A buffered UART. This would make high speed communications much more reliable. I would also like to do a version of QBserial that can use two comm ports simultaneously. QBSERIAL User Manual - V 2.10 Page 12