pcl4w.usr

C语言通讯程序库windows版

              If  you  are using a modem, you also need to be concerned about initializing
              your modem correctly and handling any required flow control.  Refer  to  the
              "Talking to Your Modem" chapter for detailed information.















             PCL4W Users Manual                                                Page 5
              1.3 Installation


              (1) Before installation of PCL4W , your Windows C compiler should already be
              installed on your system and tested. If you are not familiar with makefiles,
              refer  to  your compiler manual.  Examine the file "FILES.LST" for a list of
              the distribution files.

              (2) Make a backup  copy  of  your  distribution  disk.   Put  your  original
              distribution disk in a safe place.

              (3)  Create a work directory on your work disk (normally your harddisk). For
              example, to create a work directory named PCL4W, we first log onto the  work
              disk and then type:

                               MKDIR PCL4W

              (4)  Copy  all  the  files from your backup copy of the distribution disk to
              your work directory.  For example, to copy from the A: drive  to  your  work
              directory, we type:

                              CD PCL4W
                              COPY A:*.*

              (5)  Compile SIMPLE.C and link with the PCL4W library (PCL4W.LIB).

              Makefiles are provided for each of the  supported  compilers.   If  you  are
              unfamiliar  with  makefiles,  please  consult  your  compiler  manual. After
              compiling with the provided  makefiles,  you  can  convert  to  a  Microsoft
              Workbench  or Borland Integrated Development Environment project file if you
              wish. Compile as follows (use NMAKE not MAKE in (a) below):

                      (a) Microsoft C: Type  NMAKE SIMPLE._M_

                      (b) Borland C: Type  MAKE -fSIMPLE._B_

              SIMPLE.C  should  compile and link without any problems.

              (6) The recommended way to test  SIMPLE  is  to  run  it  on  two  computers
              connected  by  a null modem cable.  Whatever is typed on one computer should
              be displayed on the other. If you don't have  two  computers,  you  can  use
              SIMPLE  to talk to your modem. Sending an "AT" to the modem should result in
              an "OK" being sent back.

              (7) If you have downloaded the TERM test program (WTERM10.ZIP), be  sure  to
              create  a  separate  directory  and  copy  all TERM files into it.  The TERM
              program uses some functions of enhanced capability with  the  same  name  as
              used by the SIMPLE program.

              Once you have become familiar with the PCL4W files  and  have  compiled  and
              tested SIMPLE, you may want to re-organize your files into sub-directories.
















             PCL4W Users Manual                                                Page 6
              2.0 Library Organization


              The  PCL4W  library  is organized into six categories of functions. Refer to
              the PCL Reference Manual (PCL4W.REF) for details on individual functions.


              2.1 Configuration


              There are three functions in the configuration category.  SioPorts sets  the
              number  of  PC and DigiBoard ports.  SioUART is used to change the UART base
              address for a communications port to a non-standard address, while SioIRQ is
              used to assign a nonstandard IRQ line to  a  port.   (See  the  chapter  IBM
              Communications  Ports  for  more  details on standard UART addresses and IRQ
              lines).

              The  configuration  functions  SioPorts,  SioUART  and SioIRQ must be called
              before calling any other library functions.   Be  very  careful  when  using
              these  functions.   Remember that your serial hardware must support the UART
              and IRQ that you specify.  Always test any new configuration immediately.

                   SioPorts -- Sets number of PC and DigiBoard ports.
                   SioUART  -- Sets the UART base address.
                   SioIRQ   -- Assigns an IRQ line to a port.

              THE IRQ GOLDEN RULE: You may open (via  SioReset)  only  one  port  per  IRQ
              (except for the DigiBoard).


              2.2 Initialization & Termination


              There  are  eight  functions in the initialization and termination category.
              Together, SioParms, SioFIFO, SioRxBuf,  SioTxBuf,  and  SioReset  initialize
              your  serial communications system.  Your application must call SioParms and
              SioRxBuf before calling SioReset, and SioReset must  be  called  before  any
              serial I/O processing can be done.

              After initialization, SioParms and SioBaud can be called again to change the
              communications  parameters without resetting the serial port. SioFlow can be
              called to enable hardware flow control.

              Before exiting from your application, SioDone must  be  called.  Failure  to
              call SioDone can crash your system later.

                   SioRxBuf   -- Sets up receive buffer.
                   SioTxBuf   -- Sets up transmitter buffer.
                   SioFIFO    -- Sets the interrupt level for the INS16550.
                   SioParms   -- Sets parity, stop bits, and word length.
                   SioReset   -- Initialize a serial port for processing.
                   SioDone    -- Terminates further serial processing.
                   SioBaud    -- Sets the baud rate of the selected port.
                   SioFlow    -- Enables / disables flow control.













             PCL4W Users Manual                                                Page 7
              2.3 Modem Control & Status


              There  are  eight  functions  in the modem control and status category which
              provide your application with complete control over the status  and  control
              bits of your modem.

              There  are  two modem control bits, "Data Terminal Ready" (DTR) and "Request
              To Send" (RTS). These bits can be  read,  set,  or  cleared  by  SioDTR  and
              SioRTS.

              There  are  four  modem status bits, "Data Set Ready" (DSR), "Clear To Send"
              (CTS), "Ring Indicator" (RI), and "Data Carrier Detect" (DCD). SioModem  can
              read  any  of  the modem status bits.  SioDSR, SioCTS, SioRI, and SioDCD can
              only read their respective modem status bit.

              Refer to the chapter entitled "RS232 Signals" for a discussion  of  each  of
              the control and status bits.

                   SioDTR   -- Set, clear, or read the Data Terminal Ready (DTR) bit.
                   SioRTS   -- Sets, clears, or reads the Request to Send (RTS) line.
                   SioModem -- Reads the modem status register.
                   SioDSR   -- Reads the Data Set Ready (DSR) modem status bit.
                   SioCTS   -- Reads the Clear to Send (CTS) modem status bit.
                   SioDCD   -- Reads the Data Carrier Detect (DCD) modem status bit.
                   SioRI    -- Reads the Ring Indicator (RI) modem status bit.
                   SioRead  -- Reads the contents of the 7 UART registers.


              2.4 Serial I/O


              There  are  eight  library  functions  in the serial I/O category. Together,
              these functions give the programmer complete control over serial I/O. Higher
              level functions such as protocols and  smart  modem  communications  can  be
              completely  implemented  in  terms  of these functions. Refer to the example
              code.

              SioGetc and SioPutc perform all the actual serial I/O.   SioUnGetc  "ungets"
              the  last  serial  byte  read.  SioRxFlush  clears  the  receive queue while
              SioTxFlush clears the transmit queue. SioLine can be used to test  for  UART
              errors.   SioRxQue  returns  the  number of bytes in the receive queue while
              SioTxQue returns the number of bytes in the transmit queue.

                   SioGetc    -- Reads the next character from the serial line.
                   SioPutc    -- Transmit a character over a serial line.
                   SioUnGetc  -- "Un-gets" (puts back) a specified character.
                   SioRxFlush -- Flush (clears) the receive buffer.
                   SioRxQue   -- Returns the number of characters in the RX queue.
                   SioTxFlush -- Flush (clears) the transmit buffer.
                   SioTxQue   -- Returns the number of characters in the TX queue.
                   SioLine    -- Reads the line status register.















             PCL4W Users Manual                                                Page 8
              2.5 Error Detection


              There are two functions in the error detection category. They are  concerned
              with  detecting  or reporting communications errors.  Use of these functions
              can make your application significantly more robust.

              SioBrkSig can read or  modify  the  UART  break  bit.  This  is  useful  for
              signalling   the   remote  system  that  a  fatal  condition  has  occurred.
              SioLoopBack can be used to test the integrity of your UART.

              There is also a file SIOERROR.C which contains the function  SioError  which
              displays  a  error  message  corresponding  to an error code returned from a
              PCL4W function (every PCL4W function returns a code).

                   SioBrkSig   -- Asserts, cancels, or detects the RS232 BREAK  signal.
                   SioError    -- Displays  error  in  text.
                   SioLoopBack -- Performs a UART loopback test.


              2.6 General Support


              There is one function in the general support category. SioInfo  returns  the
              version  number  of  the  library  and  whether  transmitter  interrupts are
              enabled.

                   SioInfo     -- Returns the library version & memory model.







































             PCL4W Users Manual                                                Page 9
              3.0 Library Overview


              3.1 Dynamic Link Libraries


              PCL4W is provided as a dynamic link library (DLL). A DLL is characterized by
              the fact that it need not be loaded until required by an application program
              and that only one copy of the DLL is necessary regardless of the  number  of
              application  programs  that  use it. Contrast this to the traditional static
              library which is bound to each and every application that uses  it  at  link
              time.

              Since  PCL4W is a DLL, only one copy of the PCL4W code & data is loaded into
              memory regardless of the number of applications programs that use it.

              For example, more than one instance  of  the  test  program  simple  can  be
              started.   All  copies of SIMPLE can run concurrently as long as each uses a
              different COM port.


              3.2 DOS Protected Mode Interface


              Windows itself uses what is known as  the  "DOS  Protected  Mode  Interface"
              (DPMI)  to  control  changing  states  (protected  vs real), controlling the
              interrupt system, etc.  This is necessary because Windows  itself  typically
              runs  in  a  protected  state  and must change to real state in order to use
              MSDOS services.