Magnum One/Magnum One (Mid-American Digital) (Disc Manufacturing).iso/d12/debuging.arc/DIAGS.DOC

Text File | 1988-04-11 | 19KB | 412 lines

                                   DIAGS.EXE                                    DIAGS.EXE

             Special Serial, Parallel, Video diagnostics for the PC             Special Serial, Parallel, Video diagnostics for the PC

          Written by Joan Riff for:

          Computerwise Consulting Services
          P.O. Box 813, McLean, VA 22101
          [phone]


     Introduction      ____________

     DIAGS is a tool for the advanced PC user, period. It is NOT for the
     general public. This manual will not explain things in elementary terms.
     If you know what a 6845 is, and what an 8250 is, and what parallel
     handshaking lines are, then DIAGS will be extremely useful to you. If
     not, then you may have better things to do with your time than try to
     figure out this program.

     DIAGS started out as a testbed for our new interrupt-driven RS232
     libraries. The Serial Port Diagnostics were the first written, to test
     the Microsoft version 3.0 'C' interface to these routines.

     It has since grown. As we have added more assembler routines to our
     library, we have added corresponding DIAGS functions to test them.

     Additionally, DIAGS has been expanded as we experienced the need for new
     diagnostics capabilities. So the Parallel Port diagnostics were added
     when we had to debug yet another unknown printer's handshaking. And the
     6845 diagnostics were added when we needed to test various video tricks
     like displaying 30 lines of text, smooth scrolling, etc.

     As it now stands, DIAGS is a very powerful facility for:

          1) Testing all sorts of asynch communications lines

          2) Testing printer handshaking and cable wiring

          3) Examining an unknown system's DOS environment, including:

               a) Interrupt vectors
               b) Resident device handlers

          4) Directly manipulating the 6845.



     Main Menu     _________

     The main DIAGS menu displays information about the machine and about
     DOS, and presents a list of the various diagnostics that are available.
     When you exit a particular diagnostic, you are returned to this main
     menu.


     (D)isk Info      ___________

     Let's describe the weakest and least important diagnostic first.

     The DISK INFO selection from the main menu displays just about every-
     thing that can be determined about a disk. Make sure that you have a
     diskette in the indicated drive before selecting this option.

     Since there are other utilities which do just about everything that you
     may want to do with a disk, we haven't done much with this diagnostic.
     We just display disk information as reported by DOS as well as by the
     disk's Boot Record.

     Once in the Disk Info screen, the following keypresses are available to
     you:

          ESC - return to the main DIAGS menu           ESC

          ALT-V - verify a diskette by reading every sector via DOS INT          ALT-V
          025h. This is SLOW!!!! Think of this as a demo of just how
          slow INT 025h can be.

          ALT-R - reset drive. Doesn't do much, huh? That's what we          ALT-R
          wanted to see.

          A thru Z - select new drive for which statistics are to be          A      Z
          displayed. Again, be sure that you have a disk in whatever
          drive you select.

     That's it. Not much to it. If you need to do more, then use:

          The Norton Utilities
          Quaid's Disk Explorer
          Central Point Software's Option Board




     (I)nterrupt Vector Display      __________________________

     This selection from the main menu displays the system's Interrupt
     Vectors. For each interrupt, the following information is displayed:

          The interrupt number
          The interrupt vector's address within segment zero
          The Segment:Offset of its handler
          The interrupt's name and/or use

     If an interrupt points to an IRET, then that fact is reported by a
     highlighted "[IRET]" displayed after the name.                   [IRET]


     Once in the Interrupt screen, the following keypresses are available to
     you:

          ESC - exit back to main menu           ESC
          Home - scroll display back to Interrupt 0           Home
          End - scroll display to the end of the interrupts (F0 thru FF)          End
          PgDn - scroll to the next page of vectors           PgDn
          PgUp - scroll up to the previous page of vectors           PgUp
          Up Arrow - scroll up 1 line           Up Arrow
          Down Arrow - scroll down 1 line           Down Arrow



     (P)arallel Diagnostics      ______________________

     This is a more complicated set of diagnostics. It allows you to do all
     sorts of useful things with the parallel ports. We use these routines
     when we're trying to figure out whether or not some new printer is
     working properly with the system.

     At the top of the screen is displayed:

          The number of parallel ports on the system (1 thru 4)
          The number of the currently-selected printer (0 thru 3)
          The base I/O address of the currently-selected printer
          The trip character that is currently set (see below)
          Whether interrupts are allowed or disallowed during sampling

     The Parallel Port Diagnostics menu gives you the following choices:

          (I)nit printer - does a ROM BIOS "init printer" call.           (I)nit printer

          (E)nable Interrupts during sampling - toggles the indicator on          (E)nable Interrupts during sampling
          the top line, which indicates whether INTs are to be dis-
          allowed during sampling.

          (N)ew Trip character - allows you to specify a new character          (N)ew Trip character
          to be sent to the printer to 'trip' it. This is initially a
          Linefeed.


          (P)rinter switch - selects next printer (in sequence) as the          (P)rinter switch
          current printer.

          (T)rip printer - sends the current Trip character to the          (T)rip printer
          printer, and then captures the printer Status port lines using
          a special high-speed capture routine. These lines are dis-
          played in oscilloscope format, allowing you to see at a glance
          the operation of the BUSY line, ACK line, etc. Interrupts will
          be inhibited during the sampling if the top line of the
          display shows "No Ints". Press ESC to exit from the display of
          the status lines.

          (U)nique Printer setup - sends custom codes to set various          (U)nique Printer setup
          specific printers into various modes. The printers currently
          supported are:

               Data Products 8070 (and perhaps IDS Color Prism)
               IBM Graphics Printer (and certain Epsons)
               Fujitsu DL-2600 (and perhaps Epson JX color series)
               Okidata Microline 93
               Diable 630 (and C.ITOH Starwriter, F-10, etc)
               C.ITOH Prowriter

          Follow the prompts that are displayed when you make this
          selection.

          (Q)uit parallel diagnostics - to return to main menu           (Q)uit parallel diagnostics

          The following three selections are invaluable for checking
          proper printer cabling and handshaking:

          (D)ata lines - displays the parallel port Data I/O port lines          (D)ata lines
          in oscilloscope-like format. Press ESC to exit the oscillo-
          scope display.

          (S)tatus lines - as above, but lines displayed are from          (S)tatus lines
          the parallel Status I/O port.

          (C)ontrol lines - as above, but lines displayed are from          (C)ontrol lines
          parallel Control I/O port.

          The following selections send various strings to the printer:

          (F)ox message - sends a continuous FOX message to the printer          (F)ox message
          via direct I/O (bypassing the ROM BIOS). Press ESC to stop it.

          (A)scii character set - sends the complete ASCII character set          (A)scii character set
          to the printer via direct I/O (bypassing the ROM BIOS). No
          carriage returns are sent. Press ESC to stop it.

          (H)oriz and vert alignment tests - send various Formfeed, Tab,          (H)oriz and vert alignment tests
          line spacing and Backspacing sequences to printer. This is
          useful for testing the results of (U)nique printer setups, and                                            (U)nique

          to see if the printer supports true backspacing. This selec-
          tion has its own submenu, which is exited via ESC.



     (S)erial Port Diagnostics      _________________________

     If you do PC communications as much as we do, then this part of DIAGS is
     for you! It provides a very powerful look at the comm line. Its most
     intriguing feature is the ability to serve as a line monitor between two
     serial devices.

     When you select "Serial Diagnostics" from the main menu, your screen
     becomes a terminal screen. At the top of the screen is displayed various
     port information as follows:

          Whether the port is open ("OP") or closed ("CL")
          The current serial port number
          The current baud rate
          The number of data bits being used
          The type of parity being used
          The number of stop bits being used
          Whether the existing 8250 parameters are being re-used (this
               feature is only used by us, for internal testing)
          What port is being wrapped to (more on this later)
          Whether keypresses are echoed to the screen
          Whether DEBUG mode (HEX display) is set

     To the right of this information are various stats, displayed only if
     the port is open and stats have been enabled. These stats include:

          The size of the RS232 output queue (in HEX)
          The size of the RS232 input queue (in HEX)
          The status of Carrier Detect and DSR
          The number of times (in HEX) that the following have occurred:

               RING
               BREAK
               Framing Error
               Parity Error
               Overrun Error

     Once the port has been opened, any "normal" keys that you press are sent
     over the comm line by being queued into the output queue. Incoming data
     appears on the screen. Incoming and outgoing characters are displayed in
     different colors, so that you can tell what's what.

     The RS232 routines are entirely interrupt-driven. The output queue will
     be serviced only if the 8250 is properly interrupting the 8088. This in
     itself is a valuable test of proper system operation. If the output or
     input queue sizes stay "stuck" at a non-zero value, then something is
     wrong with your system.



     Besides the "normal" keys, you may use the following keypresses:


          ALT-S - switch display between port 0 and port 1 (COM1: and          ALT-S
          COM2:).

          ALT-M - bring up a menu of miscellaneous features:           ALT-M

               HANGUP the phone by dropping DTR
               PICKUP the phone by raising DTR
               RESET the Hayes 1200b by OUT1 toggle
               FLUSH input and output queues
               CRLF control (how to display incoming CR and LF)
               STATS control - turning the stats off can speed up the
                    terminal display considerable
               TRAP - control what happens when you press ALT-T to trap
                    some 8250 register

          ALT-X - initiate an XMODEM transfer. This we use to test the          ALT-X
          accuracy of XMODEM as implemented in other software packages.

          ALT-P - control port parameters. This includes:           ALT-P

               port OPEN and CLOSE
               BAUDRATE
               DATA bit selection
               PARITY setting
               STOP bit selection
               REUSE of the 8250 params (for our internal use)
               ECHO (of local keypresses) on/off
               WRAP of incoming data to another comm port
               DEBUG display toggle

          ALT-T - to trap the data lines from a previously-defined 8250          ALT-T
          register

          ALT-R - display various 8250 registers           ALT-R

          ALT-B - to send a BREAK           ALT-B

          ALT-W - wait (do nothing) till next keypress. This is useful          ALT-W
          for pausing a fast-miving display.

          ALT-Q - quit back to main menu           ALT-Q

          ALT-F - send a single FOX message over comm line           ALT-F

     Most of these functions contain their own prompts, and require no
     further explanation. Some, however, need to be explained in detail.

     The continuous updating of the stats on the top line can slow down the
     terminal display. Turning stats off (ALT-M S) can speed things up
     considerably.


     The baudrate is continuously variable, from 2 to 38400. You are not
     limited to "standard" PC baud rates.

     If you want to clear the screen and reset the stats, try switching ports
     twice (ALT-S ALT-S).

     To trap and display an 8250 register in the middle of communication, you
     must first define the register to be trapped (ALT-M T) and whether INTs
     are to be allowed during the sampling that follows.

     Having done that, you cause the trap by pressing ALT-T. At that instant,
     a special high-speed assembler routine is executed which samples the
     designated register once every 50 machine cycles or so until 420 samples
     have been taken. These sample bytes are then displayed as a screenful of
     HEX bytes. You may highlight a particular byte via the arrow keys. The
     highlighted byte's interpretation is displayed on the message line
     toward the top of the screen. Press ESC to exit this trap display.

     The "wrap" feature is very useful. It may be used to allow DIAGS to
     serve as a line monitor located between two serial devices, among other
     things. Every incoming character is "wrapped" as an output to whatever
     port you have specified as the "wrap" port. If you select as the "wrap"
     port the same port that you're using, then you have in effect become a
     full-duplex system. The serial device connected to that port will see
     its "keypresses" echoed back to itself.

     Assuming that you have two serial ports, you may use DIAGS as a line
     monitor by wrapping each port's input to the other port. You can then
     switch between ports (ALT-S) and generally watch everything that goes in
     either direction. You can turn on the DEBUG display (ALT-P G) to see
     things in more detail.



     (R)esident device handler display      _________________________________

     This main menu selection allows you to see a list of all resident device
     handlers. As you highlight each handler's name (via the left and right
     arrow keys), the device's attributes are expanded on the screen. Press
     ESC to exit this display.

     Block devices are indicated by device names of the form "BLOCKnnn",
     where nnn is the number of devices supported by this block device
     handler.




     (V)ideo Manipulation      ____________________

     If you want to do some fancy 6845 programming, then the Video diagnostic
     will be of great interest to you. It allows you to examine and alter the
     6845 registers in a most graphic fashion.

     Toward the top of the screen is a two-column list of all 6845 registers,
     and one or two of the special IBM PC video registers (the MODE and/or
     COLOR registers). There is a ">" pointer, showing you which register is                                   >
     being worked with.

     For each 6845 register, two values are shown:

          1) The original value, as set by the ROM BIOS
          2) The current value as set by you

     You move the ">" pointer to various 6845 registers via the up and down                   >
     arrow keys. As you select each 6845 register, that register's bit
     pattern is expanded on the bottom half of the screen.

     You can change the currently-selected 6845 register's value by using the
     "+" or "-" keypad keys to increment or decrement its value.       +      -

     You can also use the left and right arrow keys to move the "bit pointer"
     across the various bits of the expanded byte on the bottom half of the
     screen. Pressing "1" or "0" sets or clears the bit currently pointed                       1      0
     to. This is an alternate way to change the current value of a 6845
     register.

     The updated 6845 registers are loaded into the 6845 ONLY WHEN YOU PRESS
     RETURN. This allows you to make extensive changes to registers without
     having intermediate states foul up the display.

     If you hose things up and get an unreadable screen, just press ESC to
     exit the Video Diagnostics, then enter it again. The 6845 is reset on
     exit from the Video Diagnostics.

     If you are using a Color/Graphics Adapter, then you may press "S" to                                                                    S
     toggle Snow on or off. The upper-right corner of the display shows the
     current status of snow as follows:

          "Snow: YES" means that no effort is being made to eliminate           Snow: YES
          snow, and that snow is present (although you won't see it if
          you have a good Color/Graphics board)

          "Snow: NO" means that snow is being eliminated by our video           Snow: NO
          software.