Use: DSK3D  [switches].. DSK3 Ver:1.21
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  A 'UL CLASS II' SUPPLY WHICH COMPLIES WITH FEDERAL REGULATIONS FOR
  FLAMMABILITY AND OTHER TYPES OF FAILURE IS HIGHLY RECOMMENDED!
  RATINGS SHOULD BE 7.5-12 VDC OR 6-9 VAC WITH 400-1500 mA OUTPUT.

NOTES: A CHECKLIST FOR WHEN THINGS DON'T WORK
--------------------------------------------
  1) Spaces within options are not allowed
  2) Options must be separated by spaces
  3) Options are not case sensitive
  4) If the comm kernel is loaded and active it will be used
     used for communication unless a RESET is specified.
  5) If 8/4 bit operation is not specified and the kernel is
     not already active the 8/4 bit mode will be auto detected
  6) The LED should be lit if power is applied
  7) The C3X.DSK comm kernel should be in the current directory
  8) Check the PC port assignments and connections
  9) For applications, is the file APP.DSK in the current directory
 10) Is the application overwriting the comm kernel?
 11) Is the DB25 cable connected at both ends
 12) Does the DB25 have all 25 pins connected (not a modem cable)
 13) Is the cable line noisy (use a shielded or shorter cable)
 14) Is a security device or A/B switch box in use
 15) Operating system re-direction of a named port (network printers)
     is not supported.  The DSK uses the physical address of the port.
 16) Bi-directional ports may require Jumper or software configuration
 17) 'Peculiar' non-standard bi-directional ports may not work

CONTENTS
--------
  GETTING STARTED
  DSK FILES
  POWER SUPPLIES
  PRINTER PORTS
  DB25 CABLES
  IDENTIFYING PORTS ON THE PC
  USING AN XDS510
  COMMUNICATIONS AND DEBUG KERNEL
  MULTITASKING APPLICATIONS
  PWM DRIVER (BLINKING LED)
  EXTERNAL BOOT ROM
  SUPER SCHMIDT HYSTERESIS

GETTING STARTED
---------------
  The C31 DSK interface is designed to operate from either standard
  or bi-directional printer ports.

  To communicate the DSK must have a valid communications kernel
  loaded and executing in its internal memory.  The file that
  contains this kernel is C3X.ASM and the DSK3A output file C3X.DSK

  If no port address is specified LPT1 is used.  A scan of LPT1-LPT3
  can also be specified (TEST option) but may take a few seconds while
  the scanning process attempts to establish a communications link.
  Since the scanning process sends data to each printer port, you
  may want to turn off all other printer port devices the first time
  you use this mode of the DSK.  After the debugger starts you can
  find the LPT address by using the sF2 (shift and F2) keys to
  display the DSK's configuration information.

DSK FILES
---------
  On startup, a DSK application will first check the communications
  link to see if the DSK kernel is already loaded and running.  If a
  link cannot be verified the initialization routine bootloads C3X.DSK
  into the DSK's internal memory.

  If the application needs to load another file, that file must also
  be located within the current directory.

  DSK files are created by the DSK3A assembler

POWER SUPPLIES
--------------
  The C31 DSK is designed to use either AC or DC wall mount supplies

  'UL CLASS II' SUPPLIES WHICH COMPLY WITH FEDERAL REGULATIONS FOR
  FLAMMABILITY AND OTHER TYPES OF FAILURE ARE HIGHLY RECOMMENDED!

  Voltage ratings should be 7.5-12VDC, or 6-9VAC, with current ratings
  between 400mA-1.5A.  The power jack uses a 2.1mm coaxial jack which
  is common on many supplies.  Note: A 2.5mm jack will fit but may
  be intermittent as the internal connector size's do not match.

  LABORATORY TYPE SUPPLIES SHOULD BE USED WITH EXTREME CAUTION!
  THE 'OSHA' COMMON GROUND BETWEEN THE LAB SUPPLY, PC AND DSK
  CAN CREATE A GROUND LOOP OR SHORT IF NOT PROPERLY USED.  THESE
  TYPES OF SUPPLIES ARE NOT RECOMMENDED FOR USE WITH THE DSK!

  Laboratory supplies are typicaly grounded through the wall socket
  and or other safety grounds to prevent electrocution.  However
  these grounds can also create ground loops with other equipment
  which can potentially create short circuits.  In these cases the
  supply is typicaly shorted if a +V reference is used for ground
  essentially creating a short through the DSK's full wave rectifier.

  The C31 DSK power supply uses a full wave rectifier to generate
  the +V supply from either AC or DC sources.  A capacitive switching
  supply circuit (an LT1054) is then used to create the -V supply.
  The +/-V supplies are then regulated to +/-5V using LM7805 and
  LM7905 regulators.

  The safe upper limit for +V, which is +15V, is determined by the
  voltage ratings of the +V bypass capacitors, the LT1054 and the
  thermal dissapation of the regulators.

  The practical thermal power dissipation limit of the LM7805/LM7905
  regulators which is ~3W if no heat sink is used.  The printed
  wiring board (PWB) is designed to provide some heat sinking if
  the LM7805 is snugly bolted down to the board.

  As a standalone card the DSK consumes approximately 350mA from the
  +V supply.  The maximum recommended supply is +12V, causing a
  dissipation of (12V-5V)*350mA = 2.45W which is hot but within limits.

  Heat sinks can be added to the TO-220 voltage regulators as long
  as they do not electrically connect to other components.  Another
  option is to bolt the TO-220 body to the pwb.  The pad under the
  LM7805 is connected to the internal ground plane and the LM7905
  pad is floating.  The TO-220 heat tab of the LM7805 is electrically
  grounded and the LM7905 connected to -V.  A simple heat sink can
  be made from a piece of sheet aluminum cut from an aluminum can
  which is placed under the regulator and bent up along the
  regulators edge.

  Two resetable fuses are also included to help safeguard against
  catastrophic failures.  These fuses are not designed to prevent
  all types of damage to the DSK.  Good design practices should be
  used to make sure components are not over stressed.  The fuses
  are reset by disconnecting power and allowing them to cool.


PRINTER PORTS
-------------
   Even if you know you have a bi-directional port, these ports are
   usually pre-configured as standard printer ports until they are
   enabled either by jumpers or by software setup (BIOS)

   Knowing the correct port address is important since auto testing
   for the DSK can take a long time.

   Printer ports that use weak pullups on the data lines can cause
   noise susceptibility in long cables.  In these cases the DSK
   software drivers can be specified to have a longer timeout value
   using the T=xxx command line option.

   Printer ports that use relatively strong pullups in the status
   return lines (used for host port acknowledge and nibble data
   return) can cause a slight voltage drops in the 100 ohm EMI filter
   resistors.  At this time no incompatibilities are known, but if
   this is a problem try changing the EMI resistors to 50-75 ohms.

   A small number of very early printer ports (8086 days!) are known
   to have open collector data pin drivers.  In this case the
   printer port can replaced or pullups added to the data lines.
   Values are typicaly 330-1K ohms to Vcc.

   Some security devices will allow the DSK to be used in a series
   pass through mode.  You will need to test for reliability.

DB25 CABLES
-----------
  The correct cable to use is a straight through DB25 to DB25 cable.
  This cable will be MALE at one end and female at the other and
  should have ALL 25 pins connected.  Be careful that you do not use
  a cable which is intended for RS232.  RS232 cables are usualy easy
  to identify since some of the pins and receptacles are missing

  DB25-DB25 Ribbon cables work nicely since they are easily identified
  as having all pins connected and have the good signal quality

  The preferred cable length is less than 2 Meters (6 feet), but longer
  cables usualy work.  Twisted pair cables where the data and control
  lines are coupled tend to create glitches.

IDENTIFYING PORTS ON THE PC
---------------------------
  The standard convention is that at the PC's back panel DB25 printer
  ports are male and RS232 ports are female.

  If you have other boards in your PC which use DB25 connectors, such
  as an XDS510, do not connect the DSK to that port.

XDS510 SUPPORT
--------------
  An unpopulated header location is provided on the DSK (JP4) for an
  XDS510 emulator.  However, please be aware that the emulator halts
  the target processor effectively killing any DSK applications that
  communicates with the DSK via the printer port.

  DSK3D will crash unless the XDS510 emulator is free running

  Do not to plug the DSK printer port cable into the XDS510,
  which also uses a DB25 for its port.

COMMUNICATIONS AND DEBUG KERNEL
-------------------------------
  The communications kernel supplied with the DSK is designed to both
  communicate with the DSK's host port interface and also to perform
  debug functions such as single step, run, halt, context save and
  restore.

             DO NOT OVERWRITE THE C3X.DSK KERNEL
             WITH YOUR APPLICATIONS CODE OR DATA
              (THE LAST 256 WORD OF ON CHIP RAM)

