To:LPA11-K Users

From:  Choppy Cusachs (713) 965-4173

Subject:LPA11-K Documents and Programs


This submission consists of this document, the text of a paper  prepared
for  the  1982  Fall  DECUS U.S.  Symposium, and three FORTRAN programs,
LPAST.FOR, LPAEF.FOR, and LPATEST.FOR.  The command file, LPA11STRT,  is
a  part of VMS that was omitted in the version originally supplied to my
installation and is included for documentation.  It should appear in the
SYSMGR  directory when VMS is installed.  In addition, two figures which
are revisions of drawings in the DR11-K manual, are  submitted  for  the
VAX handouts for the 1982 Fall Symposium.


LPAST and LPAEF are usable for digital input on a VAX11/780 via LPA11-K.
Similar  programs  have  been  used by others for digital output.  While
these have not, to my knowledge, been tested on other members of the VAX
family,  I have no reason to doubt their usability.  LPATEST may be used
with a maintenance cable to test the LPA for digital output.  It  writes
out a small buffer of numbers easily recognized and reads it back in.


The two programs, LPAST and LPAEF differ in how they signal the  filling
of  buffers  by  the  LPA  software  to  the program.  As the names were
intended to suggest, the LPAST uses an AST routine, LPAEF an event flag.
The former makes it easy to use a CONTROL/C handler to exit tidily.  The
latter must be killed  by  a  CONTROL/C  or  CONTROL/Y.   This  has  the
consequence  of  necessarily  losing  any  incomplete  buffer as well as
leaving it to the system to tidy up.  Although LPAST does not check  for
a  partially  filled  buffer,  there are subroutines in the DEC supplied
software which should, in principle, permit this,  though  we  have  not
tested them.


The program LPADUMP dumps output of the acquisition programs  by  blocks
in  octal  for  debugging.   It  can serve as a template for reading the
output for further processing.