National Semiconductors SCSI Printer Controller

This directory contains all of the code used in the SCSI Printer Controller
(SPC) demonstration board, documented in the application note "A SCSI Printer
Controller using either the DP8490 EASI or DP5380 ASI".

The main source code is contained in SCSI.C and the libraries COMMAND.LIB, 
PROCESS.LIB, DMA.LIB, PRINT.LIB and ARBITRAT.LIB. The constants used in these
files are contained in SYM.H, CONST.H and COMMANDS.H. All of these files are 
written in the high level language 'C'.

The boards diagnostic software is contained in PRINTER.SRC, with it's constants
defined in EASISYM.SRC and PRNSYM.SRC. EASIO.SRC contains functions commonly
used by both the diagnostics and main code. These files are written in a Z80 
compatible assembly language, for an NSC800.

The purpose of the diagnostics is to ensure that the board is operational and
to initialize it. The main code responds to a SCSI selection and implements a
limited set of printer commands. SCSI.ABS contains the compiled, assembled and
linked absolute code, ready for downloading to an EPROM.