COMMENT ⊗   VALID 00005 PAGES
C REC  PAGE   DESCRIPTION
C00001 00001
C00002 00002	\|\\⊂'4\
C00006 00003	\F1\CSUMMARY OF PLOTTER COMMANDS
C00010 00004	\←Q\→L\F1Character Generator in MUX mode
C00012 00005	\F1\CCHARACTER GENERATOR
C00014 ENDMK
C⊗;
\|\\⊂'4;\;
\M2FIX30;\M3BAXL30;\M1BAXB30;\CTHE VARIAN PLOTTER INTERFACE

\F3\JThe Varian Plotter Interface allows full control of all functions provided
by the plotter and medium speed data flow using the I/O bus.  The 
CONO and CONI instructions access control functions.  They have the following
format:
\.
\F2___
   |18
   |19
___|20	SCAN COMPLETE		(READ ONLY)
   |21	SYSTEM NOT READY	(READ ONLY)
   |22	BUFFER BUSY		(READ ONLY)
___|23	PAPER CONTROLLER BUSY	(READ ONLY)
   |24	BOTTOM OF FORM		(READ ONLY)
   |25	(ALWAYS 0)		(READ ONLY)
___|26	READ READY		(READ ONLY)
   |27	NOT ON LINE		(READ ONLY)
   |28	SUPPLIES LOW		(READ ONLY)
___|29	VIDEO BUSY		(READ ONLY)
   |30	TEST			(WRITE ONLY)
   |31	DATA REQUEST		(READ ONLY)
___|32	INTERRUPT ENABLE	(READ/WRITE)
   |33	PI33			(READ/WRITE)
   |34	PI34			(READ/WRITE)
___|35	PI35			(READ/WRITE)

\F3\JThe definition of bits 20 to 29 are precisely as described in the 
Varian \F1"Service and Maintenance Manual for Statos
41/42 Series Printer/Plotters."\F3
DATA REQUEST indicates that the interface is ready for a word of data.  This
bit is normally on when the device is idle, and a CONO with a PI channel and
INTERRUPT ENABLE will cause an immediate interrupt.

A DATAO instruction provides data for the plotter.  The 36-bit data word is
divided into four 9-bit bytes.  In each byte, the high order bit indicates
whether the plotter will interpert this byte as data or control.  If the bit
is off, the remaining eight bits are data which will be used for characters
or graphics, depending on previously provided control commands.  If the bit
is on, the remaining eight bits are interperted as commands as described in
the Varian plotter manual.  The high order byte in the word is given to the
plotter first, followed by succedingly lower order bytes.  When the word
is exhausted, the interface will interrupt on the PI channel indicated.

For diagnostic purposes, a DATAI instruction will read whatever is currently
in the interface buffer.  In addition, a CONO instruction with the TEST bit
set will cause the interface buffer to shift left 9 bits.  These features
are only useful if the plotter is disconnected or off-line, otherwise the
data will be changing during a DATAI, or a CONO with TEST will cause random
extra shifts and mung the data.
\.
\F1\CSUMMARY OF PLOTTER COMMANDS

\←=400;\→A\F2DATA	COMMAND

500	CHARACTER GENERATOR SELECT (THIS IS THE DEFAULT ON RESET)
\←L\→Q\←A\→L\F3\JIdentifies all following data transfers as alphanumeric
data.  The command is stored internally in the Statos and is
changed only if a raster write select code is received.  System reset
selects the character generator.
\.
\←Q\→L\F2
560	SELECT CHARACTER GENERATOR IN MUX MODE
\←L\→Q\←A\→L\F3\JThis mode is complicated and is explained below.
\.
\←Q\→L\F2
740	RASTER WRITE SELECT
\←L\→Q\←A\→L\F3\JIdentifies all the following data transfers as raster
(graphics) data.  The command is
changed only if a character generator select control
code or a system reset command is received.
\.
\←Q\→L\F2
644	AUTOSTEP RASTER WRITE SELECT
\←L\→Q\←A\→L\F3\JSelects a mode of operation in which the line sync and
step commands are generated internally after entry of
a full line of raster information.  Once the Autostep
mode is selected, each raster scan must contain a full
line of data.
\.
\←Q\→L\F2
445	AUTOSTEP MODE RESET
\←L\→Q\←A\→L\F3\JClears the Auto step mode.  Autostep is also cleared by reset.
\.
\←Q\→L\F2
443	LINE SYNC/STEP
\←L\→Q\←A\→L\F3\JCauses the paper to advance one step increment.  If there is data in the
buffer, it is printed.
\.
\←Q\→L\F2
663	FORM FEED (NO-OP ON 22 INCH WIDE PLOTTER)
\←L\→Q\←A\→L\F3\JCauses fan-fold paper to move to the top of the next
form.
\.
\←Q\→L\F2
464	STEP
\←L\→Q\←A\→L\F3\JCauses the paper to advance one step increment.  If there is data in the
buffer, it is printed.
\.
\←Q\→L\F2
665	SLEW
\←L\→Q\←A\→L\F3\JCauses the paper to advance 8.5 inches for each command given.
The movement of the paper resulting from one slew command
is sufficient to bring the last line printed into view.

The following commands are valid when in character mode (MUX sub-mode or
not).
\.
\←Q\→L\F2
000	NO-OP
014	NO-OP (if not using fan-fold paper)
015	NO-OP	<carrage return>
200	NO-OP
214	NO-OP (if not using fan-fold paper)
215	NO-OP
\←L\→Q\←A\→L\F3\JThese commands do nothing and continue immediately.
\.
\←Q\→L\F2
012	LINE FEED
212	LINE FEED
\←L\→Q\←A\→L\F3\JCauses the current buffered line of characters to be plotted and the paper
advances one character line space.  If in character MUX mode, the next
command must be a RASTER select.
\.
\←Q\→L\F1Character Generator in MUX mode
\F3\JIf it is desired to overlay character generator symbols with graphics, the
following proceedure must be followed.  First issue the command SELECT CHARACTER
GENERATOR IN MUX MODE (560) and send a full line of characters including a
<line-feed> (012) at the end.  At this point, RASTER mode must be selected,
either stantard (740) or AUTOSTEP (644) mode.  All data now presented to the
plotter will be graphics "OR"ed with the previously supplied characters.
The user must ensure that enough raster data is input to the Statos to cover
the area in which the characters are to be printed.  The plotting rate of the Statos
slows down during the actual time that data is being multiplexed because
of the overhead required to manipulate the data from two sources.
\.
\F1\CCHARACTER GENERATOR

\F3\JThe Character generator model number 146 has the following character set.
The 200 bit in the character code is ignored.
\.
\F2
CODE	CHARACTER
000	<no-op>				020     ∞
001	<paragraph mark>		021     <triangle>
002	<degrees>			022	<box>
003	<squiggle>			023     <box>
004	<pounds sterling>		024     ∧
005	<cents>				025     <copyright>
006	<shourt dash>			026     1/4
007	<times>				027     3/4
010	1/3				030     <sigma>
011	≥				031     ≤
012	<line-feed>			032     <divide>
013	<dagger>			033     <double dagger>
014	<form-feed>			034     <epsilon (cap)>
015	<no-op>				035     →
016	←				036     ↓
017	2/3				037     <registered trademark

\F3\JAll other characters conform strictly to USASCII, including 137 for "_",
76 for "~", and 177 for <block>.
\.