Vector Graphic Flashvvriter II User manual

Flashvvriter IT
Users GUide
___ ,--LO=l CS=lAi'l-iC inC.

FLASHWRITER II BOARD
Manual Revision 3
March 29, 1979
Copyright 1979 Vector Graphic Inc.

Copyright 1979 Vector Graphic Inc.
Revision Numbers
The revision number and date of release of each page herein appears
at the bottom of each page. The revision number and date of release
on the Title Page corresponds to that of the page most recently
revised.
Revision 2 2/7/79

'['he [o'la[;,in~riter IT Goard '~I)ld Il::,,"'l!)ci(~r 1,~; sclcJ "as is", ",-'ith all
fd U 1 t san d wi t 11 0ut ,HI jwar: r '1 Ii Ljfe ,t~" )'.: ( f:: XPLe sse ci 0ri Iii P 1 i I,: cl ,
inc 1u din 9 any i];1 P 1 iedW 3 f' ran ty ;; riitn (' s s 1: 0I.' in ten ded use 0 j-
iflcrchantability. BOWeV(;l-, the <;,J;,,\,"i-= liOLviithstandinlj, Vj;CTU](
GRAPHIC, INC., will, for a periou 1.;1 ninety (90) days follovlin'j
delivery to custor.,er, reEJuir or reI"" co ;"ny E'l2shwriter II Hoare;
that is found to contain d(~E("ct,:; in )!;dt~:'r.ials or workmanship,
:)t~uvid('Ll:
1. Such defect In:natf;ria:,
ti:ile t'l
l
-= Flashwri,t!'~r II l~()al-(,: u~i,
'dctorYi
')C \;ur1:mansbit; c~xisted ,;d', till::
till, VL:CTuH Ghl\PLJIC, 11,:('.,
2. VEC'I'ulZ GRAPHIC, I!~(~.I "C 'jivt::n notice of lnt.: r--rl-"cise
J~[ect claimed withi~ ten (10) days d[tcr its discovery;
3. The Flashwr i tel:' I I 150ar,1 i:, proIlllJtly returnr::ci to VSC'l'O l~
Ckl\PHIC, INC., at customer's expens',:" for examination uy veCTOR
GlV\P1IIC, INC., to confirm the all0(Jc,J rJeJ:cct, and for sub~.,equcJlt
rcpaic or replaCel1lent jf found to l.Je H, orJer.
i':'<-'i/air, replacement or. cor't'cctil)t~ (,: any deLects Ifl i1luterial ur
wOl'kmanship "Jhich aro (3iscov(~t"'~rJ aft".:::::- c:xpi1.-ation of the: per-ioc SCot
!ut-th ",bove will be perforhled I;)' \/CC.'l'l;'; I;P./"d~t;.LC I INC., at Buyer Is
(expense, provided tbe F'lasbw-ritcr 11 l3o;.o:ro is returne'21~-als0-:L
Tf UY E:-~ sex pen s e, to VEe T 0 lZ GH Ii F H I ,~: I 1[-./ C ., for sue h rep air,
l:'C:placement :,.)r cOI:-recti.on. In 1"F,rforIl,lily any rCi!air, reFlacelii0nt. cr
correction after expiration uL r.tH' lJerioJ set~ forth above, 8uj(,or
~iJl be charged in addition to the cost of parts the then-current
vr,;C'rOi~ GRAPHIC, INC., repair r,itc. At the present time the
a p p 1. i cab 1 era te is $3 5 • 00 L)C tlHc [i rs tho ci 1.-, and $1 8 • 0 0 l? e r 110 u r
fur every hour of work required t,hereafter. Prior to cornmencinc.J Glni
c
epa i r, rep 1 a :::: e men tor cor r '..:.' Ct 'L C Ii 0fd .:; r'2 Ct sin LJ t e r- jci 1 t) C
'W 0rk III a n s hip d i ',; C 0 v ere d aft ere x 1 ,i rat ion 0f thE: pee icc; f () :c
no-cost.-to-I3uyer repairs, \/L;'~:'l'UL ChJ\"'lIi:, U!~,. I will ,SUL,~iit to buyer
i \~ r itt C 11 cst i IT, a t f; (, f thE: Cx 1:- e ~~ t c: cl ': lJ i; IY co c" Ci Ii c: \i LCT () i<. CR 1'.. PI 1.; L' t
L hi C ., \'1' ill not c () IfL,ne nee r e l' ai:-- un tsU',: j : (, I, ,11 ;,:; as the IN t' 1t ten
estjrd2te of char'::1es has bL"en ).:-c:tl,n;l!~d by buyer to VEC'TOI,~ GIU,Pl1J.c.:,
INC., signee, by d!Jly a'Jthor'ized n;'))"'~,c:,!tati.v::: "utlJo)'izing VL,-',Ul~
';Fi\PHIC, INC., t,) COfr.l!lence wiL,tf,i ,'Cflal! yior};, involve'u. VEC'i'OT<
Gl,z/\PHIC, INC. I shall haVe: nn IhlllSe,t i,on to cepa i;:- I replace or
corn::ct any Flashwriter II Board unt.il (he ','>'ritten estimate has bee'l
r~turned with approval to p~ocee(j, and VECl'Uf" GRAPHIC, INC., Day at
tts option also require [JLepayment of thee estimated repair charyes
pcior to cornmenciny "vork.
I(epair A'3reement voiu if the enclosed card i.':, not returned to Vl::C'l'OJz
CRAPHIC, INC. \,yithin ten (10) days of "'no consumer LJurchase.
l/ 3U/? 'j

lector Graphic P13shwriter II Board
TABLE OF CONT~~'~
i: .'
Hepa; r j\,S re(:r:1ent
TaDle of Contents
Ie Int:c6ccticn
02scription of the Board....... ...•..... 1·
~2 ~esc~~ption of the Manual 6 ••• ~_~.~.n ~ .. ~
',,:::C'-':/ cf. Operation
", "
r.-', " _~
i:~' (':' \;' b _I rrdPo;.·· t6 -.;: It; '1' ~ II> " eo •••• , " .', 0; *' , . -
" .....
~. ~~ ~;cd;,:oi",·.:al Sync Circuitry •..•• c ••••••••••• " c·. <
2. j Vert~cal Sy~c Circuitry •••..•••.••••.••.••..•..• ~-~
),':; ':2:.,c:"yl\ddress Multiplexer ,.G., •• , ',c'
2 • 5 (-'.2;(,0 ry La t c h 0 ••.•••••••••.••••••.• ,. • • • • • • •. •• .', - • " • " ,:." •
2.6 Char~cter Generator and Shift Register..... ,;·3
c.~ M0oilor ROM Circuit ••.•.••.•.•••••..•..••.••..
III,; :Jserls Gui·de
3.1 Modifications to the Standard
Co ,1 fig u rat ion ••••••••••...••••.••..•. " ... ' •...
~.!.J Creating a New Character Set •••..•..
~,,1.'2 Changing the Address of Video rVje=-~,;:):cy.
3.; . .:\ P..1tting a Monitor PROf"'! on the BOEd:-C
3.100 Address of the Monitor PROM on the
30 a i:" dt ••• c • ,_ 0; ('r (_ " ~. (
.-
.j
.. ~ .'.
. .. .~. ~- ~;
3. * 1. .G
3,1.'7
3. L8
3.1.9
3.1.10
3~1.-ll
3 • .i. • 12
S?ec~fying whether M0nitor PROM cn
Board is 2708 or 272.5 ••.•• ,
E r:.a '~,,: .. ~. i ;l.g a ] ~ITI~) 0nft e~:; et .. ~ ~. C< .. ~, q. I> .. .,. ••
Chang ~ ng the Keyboa rd Pc' rt l\dd r ess .. , ,
Changing the Polarity of the
Vertical Sync Sign.:] .•..•.
Obtaining MWRITE •.•...
o
••••••••••••
Changing the Polarity of the
Keyboard Strobe ••••.••.••• ,." .•.... ," ~
Using Interrupt Driven Software, •.• "0 " •• ,~-~~,
Supplying a Keyboard wi~h a
Negative Vol';;'age Powe:' SuppI~' ..
Usi~g a Spare Key on the
Keyboard fol.' Reset '.' •.•• 0.' .,
Accessing the 60 Hz Veitical
Blanking Signal .••••.•.....
". i- . ", (";
/·i iJJ ':j

vector Graphic F13shw~i' ~L II Board
Section
3.2 Programming for the P1ashwriter II Board •.••..••• 3-6
3.2.1
3.2.2
Vector Graphic Monitors ••.••••.••••....••• 3-6
Displaying Characters Without Using the
Vector Graphic Monitor Video
Dr i ve r 3- 8
3.2.3 Producing Reverse Video ••.•.•..••••••.•••. 3-8
3.2.4 Determining Whether a Character
is in the Keyboard Buffer •••••••..•• 3-10
3.2.5 AccessiLg the 60 Hz Vertical
B1Enking Signal ...•..•..••.••.••..•. 3-10
3. 3 Adjustin~1 Your TV Monitor •••..•••..••••••...•••• 3-10
.3.4 Connecting the Board to the Video
Display and the Keyboard ••••••..••••••.•.•• 3-11
3.4.1 Connecting a Video Display Requiring
Separate Sync and Video •••••.•..•••. 3-12
3.4.2 Connecting a Video Display Requiring
Combined Sync and Video •...••...•••• 3-12
3.4.3 Connecting a Keyboard .........•......•... 3-13
IV. Diagrams
Character Set, Low Order 128 Characters •....•.•.•••.•• 4-1
Character Set, High Order 128 Characters •.••••..•..•.• 4-2
Blank Form, Low Order Character Set •....•.•.•••••••..• 4-3
Blank Form, High Order Character Set ••.•••..•.•••.••.• 4-4
80 X24 Video Display Module Block Diagram •.•••••••..• 4-S
Board Layout with Jumper Pads ..•.•••••...•.••...•••.•. 4-6
Schema tic ~ 4-7

Vector Graphic Flashwriter IT Board
I. INTRODUCTON
1.1 Description of the Board
1-1
The Flashwriter II Video Board is Vector Graphic's advanced 80 x 24
memory mapped video board. By "80 x 24" we mean that the board
displays characters on the screen in 24 rows of 80 characters each.
Each character is made up of an 8 x 10 matrix of dots.
The Flashwriter II can be installed in ANY S-IOO 8080 or Z-80
computer, including existing Vector Graphic computers, in order to
convert the existing memory mapped display to 80 x 24, or to make
use of memory mapped video for the first time if a serial terminal
had been used. It can be used with almost any standard computer
video monitor, since it can produce either separate or combined
video and sync signals. However, the monitor must have a band width
of at least 12 MHz. The board is definitely applicable to the
Vector Graphic Mindless Terminal, which requires separate signals.
(Note: in this manual, the word "monitor" refers to a video display
unit, and the word "Monitor" with an upper-case M refers to a kind
of canputer program which handles basic housekeeping functions for
the computer.)
The Flashwriter II makes use of the most up-to-date ideas in circuit
design such as flicker-free updating of the screen, separate sync
outputs for video monitors requiring it, on-board user-programmable
PROMs storing the character set, on-board socket for a video-driver
and/or Monitor, Jump-on-Reset capability, to be used if the on-board
video-driver socket is used, the availability of inverted or
non-inverted vertical sync signals, the availability of combined or
separate video and sync signals, and the capability for reverse
video. To make the board adaptable to many different systems, you
are free by using juwpers to specify the memory addresses used by
the on-board video memory RAM and the on-board vide0 driver.
Further, a parallel keyboard input port is incorporated on the
board, with the port numbers changeable by jumper anywhere from 00
and 01 (status and data) up to OE and OF. Although the board is
shipped jumpered so that it strobes the keyboard data into the input
latch on the rising edge of the key-depression strobe, a jumper car.
be installed to strobe the data on the falling edge, as required by
some keyboards. The board can also be jumpered to generate an
interrupt when a key is depressed, instead of waiting to be polled.
A particularly ~seful feature of the board is the ability to accept
a user-created character set, which can be either a 128 or 256
character set. If a 256 character set is desired, then the user
must sacrifice the use of reverse video. The board is shipped with
a 128 character set, on aPROM. This set consists of the 96
standard ASCII characters and 16 special graphics characters which
can be used to build graphics images or large characters.
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1-2
Vector Graphic Flashwriter II Board
Instructions are provided for creating your own character set and
encoding it on 2708 or 2716 EPROMs (the latter for a 256 character
set), if desired.
Instructions are given in this manual for writing programs to use
the board. In addition, the user can purchase, if not already
included in his computer system, the Vector Graphic Extended Systems
Monitor with video driver, Version 3 EV-II. Before making this
decision, section 3.2.1 should be read. Use of this Monitor will
eliminate some or all of the assembly language programming necessary
to use the board. The EVIOS program, a sophisticated video driver
used with the Flashwriter I board, canNOT be used with the
Flashwriter II board, but Version 3 of the Monitor makes it largely
unnecessary. For user's familiar with Flashwriter I, this is partly
due to the fact that Flashwriter II does not have a separate memory
block containing character attributes. In Flashwriter II, there are
no special vertical and horizontal lines outside of those in the
graphics characters, there is no reduced intensity, and the graphics
characters are produced in response to ASCII codes 00 to IF and 80
to 9F.
The Flashwriter II board is a major addition to the Vector Graphic
product line. Vector Graphic has now applied its well known
excellence in video display quality and product flexibility to the
creation of an advanced 80 x 24 video display board.
1.2 Description of the Manual
This manual provides a discussion of the theory of operation of the
Flashwriter II, and a User's Guide describing 1) when and how to
modify the board's electronics and PROM's, 2) how to program for the
board, how to adjust the TV monitor, and how to connect the board to
keyboard and video. Since the board is not sold as a kit, assembly
information and parts list are not included.
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Vector Graphic Flashwritpr JI Board
II. THEORY OF OPERATION
2-1
A block diagram of tbe v ideo d ispl ay module is shown on page 4-5.
Each of the blocks is comprised of several integrated circuits as
shown on the schematic diagram on page 4-7.
2.1 Keyboard Port
Starting with the keyboard port, U46 is an 8 bit latch which
internally stores the data from the keyboard coming through Jl wh~n
the STB (pin 11) input goes low. A jumper option allows the correct
strobe polarity to be selected. U46 contains a service request fli~
flop which is set by the same strobe edge that latches the data,
causing INT to go low (pin 23). This signal can optionally be
connected to PINT on the bus (pin 73) for interrupt driven keyboard
input, or can be tested by accessing the status port. Two adjacent
ports are always occupied by the status and data with the status
being the lower one. The port address is decoded by U39 and the
as soc i a ted se ct iOllS of U27 and U38. A jumper allows the select ion
of port addresses from 0 and 1 to E and F. (Each pair of ports
refers to status and data, respectively.) Signals INPS and INPD
enable tristate bus drivers U45 and U21 to gate the INT signal and
data onto the bus at the appropriate time. Both inverted and
non-inverted status are available, for keyboard drivers using
different conventions. The vertical blanking signal is also
available, from the status port, for use as a60Hz clock signal, or
for synchronizing data transfers witb the vertical retrace.
2.2 Horizontal Sync Circuitry
The timing for the characters, horizontal blanking and horizontal
sync pulse is provided by U15, U29, U3 and Ul. A crystal oscillator
at 14.318 MHz provides the clock for all the signals. This is the
frequency at which the individual dots making up the characters are
displayed. U15 divides this clock by 8 to generate a character
clock output every time anew character is to be displayed. This
signal is further divided by U29 and U3 to generate a horizontal
period of 63.69 micro-seconds. The outputs HO-H6 are binary 0ut~uts
representing the 80 character positions per line. H7 goes high at
the end of the displayed line of characters, and is used as the
horizontal blanking signal. At the count of 207, decoded by U2 pin
8, the counter string is preset to the value of 94 and starts
counting over agai~. This signal also triggers Ul, a dual one-shot
to generate a horizontal sync pulse. The delay of this pulse can be
varied by the hor1zontal position potentiometer to allow centering
the display on the TV screen.
~ev isi 0'1 1 1/ ~, 0/'/ '9

2-2 \~ctar Graphic Flashwriter II Board
2.3 Vertical Sync Circuitry
The vertical sync counters U6, U4 and U5 are clocked by the
horizontal sync pulse from Ul pin 5 to produce a count from 0 to
261. Each row of characters occupies 10 scan lines. U6 is a decade
counter, so it generates a terminal count (TC) every 10 lines. The
displayed characters occupy 240 lines, and U19 pin 12 goes low at
the count of 240 to blank the display. A vertical sync pulse is
generated by a section of U5 and U20 pin 1 which is 2 lines long,
from 240 to 242. This is slightly shorter than a standard TV sync
signal, and produces a minimum disturbance to the horizontal sync of
the TV. The video output remains blanked until the counters are
preset to 0 at the count of 261 for a total of 262 scan lines.
2.4 Memory Address Multiplexer
The on board memory is multiplexed between the CPU and the sync
circuitry. This is done using tristate drivers U40, U41, U28 and
the tristate outputs of U16. Thus when the CPU addresses memory,
the address bus signals drive the memory address inputs, and while
the characters are displayed on the screen, the address inputs are
generated by the sync circuitry. One complication is that since 80
is not a binary power, there is not a convenient separation of
horizontal and vertical address inputs. 80 is divisible by 16, so
the least significant 4 bits from U29 are applied directly to the
memory address inputs. The remaining 3 hor izon tal counter ou tpu ts
H4-H6 and the vertical sync signals VO-V4 are mapped into 7 bits
using a 256 x 8 ROM U16. This effectively maps the displayed
characters in a linear fashion into the 2K of address space occupied
by the memory. Since 80 X24 = 1920, there are 128 locations in RAM
that are not displayed on the screen.
If the memory is addressed by the CPU, it will not be able to
generate the proper output to be displayed on the screen. This
would cause undesirable glitches, or flashes of light on the screen
as the display was being written into. To prevent this, access is
inhibited by the CPU except during the horizontal retrace interval.
U12 provides the necessary arbitration and pulls PRDY (pin 72) low
to put the CPU in a wait state until it can access the memory. Two
sections of U12 provide delays to ensure that control is transferred
properly. U12 pin 13 provides a delay to ensure that the CPU has
finl.shed its current memory access cycle, and U12 provides a similar
delay to ensure that the memory access time is satisfied before the
CPU proceeds. ~he data bus is buffered by U44 and U33.
2.5 Memory Latch
The combine·j access time of the ltlemory and the character generator
ROM exceeds the character period of 558 ns. Thus the data is
"pipelined" using U34 and U35 to latch the memory data. This
Revision 1 1/30/79

Vector Graphic Flashwriter II Boar~
2-3
provides 558 ns access time for both the RAM and character
generator. The output of U34, U35 is delayed by one character clock
period from the sync counter outputs, while the data strobed into
the dot shift register U8 is delayed two character clocks. To
compensatp for this delay, it is necessary to delay the horizontal
blanking signal also. This is done using sections of U35, and the
output of pin 12 is H Blank DLD, the delayed horizontal blanking
signal.
2.6 Character Generator and Shift Register
The dot patterns for each character are generated by U22 and U23.
The 8 bit output from these user programmable EPROMs is supplied in
parallel to U8 which shifts the dots out at the high dot clock
(14.318 MHz) rate. The addressing of U22, 23 is arranged so that
there are several options as far as the ROMs are concerned. U22
generates the top 8 lines of each character cell. If only upper
case characters are used with no descenders, this is the only ROM
required. For the descenders of lower case characters and graphic
symbols, a second ROM is required (U23) which generates the bottom
two lines of each character cell. If in addition, a full 256
characters are used, U22 is replaced with a TMS 2716. For the 128
character ASCII character set, the most significant memory bit is
not required. This is normally jumpered to U7 pin 12 to control the
reverse video. If the 256 character set is used, this bit is
connected to U22 pin 20 to select the upper half of the ROM. More
information on this subject is provided in the User's Guide, Section
III of this manual.
2.7 Video Combiner
The horizontal and vertical sync signals are available at J2 pin 4,5
for monitors such as the Ball Brothers TV 120 used in the Vector
Graphic Mindless Terminal which require separate sync and video.
U19 pin 8 is the combined video and blanking signal which is
available at J2 pin 3 with the proper polarity for the Mindless
Terminal. The sync signals and video ure combined in the circuitry
associated with UIO, and are available at J2 pin 1. The horizontal
and vertical sync are first combined in U7 and then summed with the
video using the open collector outputs of UIO and the resistive
ne~work. The resistor values have been chosen to give the proper
sync and video amplitudes and to provide a 75 ohm source impedance
to drive a terminated video cable. Very good video rise and fall
times are obtained with this circuit. In order to compensate for
the limited bandwidth of most TV monitors, some high frequency
preemphasis is provided by the 470 pf capacitor shunting the 100 ohm
output resistor. If the video display is not satisfactory, it may
be improved by changing this value.
Revision 1 1/30/7~

2-4 Vector Graphic Flashwriter II Board
2.8 Monitor ROM Circuit
A socket is provided for a 2708/2716 ROM to be used as a monitor
and/or video driver. U26 selects both the address for the video
memory RAM and also the ROM with jumper options every 2K in the
upper 16K of memory. A Jump on Reset flip flop consisting of U9
sections has two functions: 1) to disable RAM after the system is
powered up or reset; 2) to enable the on-board Monitor ROM at
address O. If the first three instructions of the ROM are JMP XX03,
where XXOO is the normal ROM address, then when the system is
powered on or the reset key is depressed, these instructions will be
executed, causing the CPU to continue executing with the 4th byte of
the ROM. After the jump takes place, the circuitry automatically
resets the flip flop and restores normal operation of the RAM.
Circuitry is also provided to generate MWRITE, a signal produced in
some computers by the front panel. This is not required in Vector
Graphic equipment as it is generated by the Z-80 CPU board.
Revision 1 1/30/79

\ ~:.;,
3 _1
The sub-sectio~3
modifications h'
Board, both to
boa rd. In e c c j':
board is usee 0
might make the m:
This section :Sil'
constitutes tb~ ~
find the locatio~
refer to the di28'
.=3:-.;..- _'-,_,--l __ -,C_r_e--,-a t.3!1.g ,.i_
Lj_
! ~' .
l,. i J:
! ~ ,
The Flashviriter j1 !'
ASCII character EEl
find a diagram 00 t'
characters can be U~0
large variety of
characters are th0~e
when the correspO~~l
code for each e112:! c;tc:
each ~tored byte. !
into r'everse vide:: I;.
normal video. RE~cr3e
found on page 4~2,
'11
r: '
~ l~J c; (' ,~:: c t. '~:, r
\, G U \: :., J _L
~ ',; ,,;,;: t
t. '::. :,~, (' ,:.:;:';:;: t. -2 '
The characters ail::; ~''- "(
character consists of'
page 4-1. PROI~ LJ2::: st'
stores the l~st 2 1= ,
addresses on U22 cel': '.'.:'" 1.,',
come the second J ~ 1':0 '. i
eighth line of ;;:
characters wit~ (Me
('
en
"I? Ec
(: 1.'-,
'.
L) (' rj
If yo 11 wi sht ere j, jp ,.' ",' "', '"
pair of PROH's, '):'~,~~,t: [CO''';e,',!, ,1
nominal fee, Vectc," (~r2Dhic I"i! '[ ,'v ',h":'
Vee tor G rap hie hi'" 'I; i':, '" :
a p pro p ria tee eI 1 :", ", 2ri " I'V : r! r" ie, 1, r i,
for man p age IJ -, :, !; , l.
UP per - cas e c h (J rae t ( " " :) :, ~ j' r"
Chai act e r, you \, ill I'j i' I "j \ 'j • '
cha rae te r PRO t1 1.3 fr () in Vee t CJ}" C" c' n I~, , ('
directly to make arrang~m~nLs.
You can a1 so -:; r e ~; te ,:' fu 1. 1,"') (
Revision ~ 3/~S!{~
1~::::~(.,-j~LJcd aL~ove~ [-'or 2.
(, C' 1" V cu. You m (; ~' T. Pr f) 'J idE-
o. c r.r '(" CJ <"? Y ;, en in g the
US0 th2 blank character
YOIJr:~E:lr to (:~nly
't.., C;;'ii 'S -~'l' (; ]i n f2 sin 2(3 C 'n
\~ I f~1 ~ T (\ () r-"' 0 0 r" C LJ .5 t() m
: " c;." r: con t. act t [-\ e c CIT! P c: tl y

3-2
V~ctor Graphic Flashwriter II Board
TMS 2716 2K x 8 PROM or eyuivalent for U22, and 2708 for U23. The
data is organized in the same way as with a 128 character set,
except that 256, instead of 128, consecutive addresses contain the
first lines of all the characters, and so on for each line in the
character matrices. with a 256 character set, you sacrifice the use
of reverse video, because all 8 bits of each byte are used to
designate the character. Vector Graphic will also create the PROM's
for you for a 256 character set, for an appropriate fee. Use both
of the blank character forms found on pages 4-3 and 4-4 when sending
your character set to Vector Graphic, putting the first 128
characters on the first page, and the second 128 characters on the
second page.
The board is shipped jumpered for a 128 character set. Jumpers must
be changed as follows for a 256 character set.
128 character set
Area I 2 - 1
Area B 2 - 4
3 - 1
Area E 1 - 3
2 - 5
256
character set
Cut 2-1
')
-1
L.
3-4
Cut 2-4
Cut
3-1
1-3
Cut 2-5
2-4
3.1.2 Changing the Address of the Video Memory
2K of RAM are provided on-board for storage of the current screen
image. Since the screen contains only 1920 character locations, the
last 128 bytes of this RAM is available for any other purpose. The
board is shipped with this RAM addressed at DODO. Since the Vector
Graphic Extended Systems Monitor assumes this location, do not
change it if you are using the video driver in this Monitor, unless
you are willing to modify the Monitor on PROM. If you do want to
change the address of video memory, a jumper must be changed in Area
F. The jumper which determines the address of the RAM goes from pad
2 to one of the 8 pads below it. Each of the 8 pads corresponds to
one address, as indicated in the diagram below. Cut the existing
jumper and install anew one as required.
F
cooo
C800
0000
0800
E 00 a
E 80 a
Faaa
F 800
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3-3
3.1.3
Pu_tt:_~_~g a Monitor PROM on the Board
The Flashwrit.er II board is not shipped with a Monitor PROM on the
board. However. socket U42 is available for either a1K 2708 or a
2K 2716 PFlOt'; ~'F,jJln,; ~1 ~1onitol~ and/or video driver. This program can
be one of tLc~:J(-ct(yC Graf:?bic t\1onitors (see section 3.2.1) 0:- one you
have writtE;r Y~)lE~,:cJ,f (sec: section 3.2.2.) (Note that 1.n Vector
Graphic c;~}np .. ';)c~.; t:i:E l-lcJnitor PROH resides on the 12K PROM/RAM
board.) ~U y':'i... ,it) .; .:1stal.l a Monitor PRO~1 on the Flashwriter board
in U42¥ it ,-,j:,~,' ',,~:,:;t :::;'1"1 if the board is properly jumpered. Refer
to sect ionE:, :j, '. ,i ,) ,T and 3.1.6.
3.1.4 the Monit,or PROM on the Board
If you chooE." U :':3;, the socket provided on the board for a Monitor
and/or Video L~ :\-"L t~j{Ur<f you must put a jumper in Area F to s}>ecify
the addres~~:L ~:j1" PhC:!',j. The jumper goes from pad 1 to one of the
8 pads bele\i :"t. :::,':1', Gf. ~be 8 pads corresponds to one address, as
indicated :lL L~:("'':'''isr':i1n in section 3.1.2. Obviously, you cannot
use the sam(~ ui.C'r.}. tyC nf:=mory that is used for the on-board RAM.
3.1.5
If you ChOOH, C ,; U,~;,: U'Hc socket prov ided on the board for a Moni tor
and/or VideG ~:~"~\j'.'i' PIWM, the chip used can be either a lK or 2K
chip, i.e. c: 27C:~ Cil': 2716 respectively. The board is shipped to
accept a lK r'i.();vj, Q;:: determined by the jumpers in Area D. In order
to use a 271t f'~,;GM, cut the jumpers from 1 - 4 and from 2 - 3 and
replace with it jUf:lpet from 1 - 3 and a jumper from 4 to Area M.
(There is only ULi: i"j"rl in P.rea ~1.)
3.1.6 Enabl inQ ,} '1",:
______ . ._~ .... -" .. . .' ._ ... --"._---
At this time/dlc" ;:A:":r,',,t"}ter II boar-d is not shipped with a Monitor
PROM, and th,:::,t-ci:u;- ;-;:J".:. :'esponsU:::le for Jump-an-Reset. If you
install (2 FECh,,)i ." ;:;oi'lrd, yell 'Ni.:~ IJant to enable Jump-an-Reset.
1ft his i sen it L1 '.' I"'; i '_ 11 '.:: 11 ,~ 0P (: Lj ;,: f) r power son the s y s t e In 0r
depresses i.b" L',:,rH ,.;'I£,el re':et :3vvitch, the CPU will automatically
read the fit'st j Lyle':; 01 th,' ;'''1uniLo:c PROM on the board. 1'hus, the
first thrc,1? Lyt,.:~'3 i:J[ '::.;:;,',: Y:onit0r PRCI<i must be a jump to some other
address in men,ury. U:;u,.:l:Lli tlt,l<3 address is simply the next address
on the same PI\iJt'1, !'ILEilE:'Ji the tJes inni ng address of the PROM plus 3.
In order to enable Jump on Resot, install a jumper in Area C from 1
-
2, and in 'In-,ld t~ [n,di, 1 ~ 2. If you are writing your own Monitor
PROM, then ttl;, L)'!(lSt'r..d: whicLlJeyins at the 4th byte of the PROM must
be an appropri~t0 r~~~onse ~o the reset.

'\ ! ~ .-,.l
, '~:raph ic Flashwr i tel' I I BOii cd
3 .. 1.7
Changing the Keyboard Port Address
:,rormally the keyboard is accessed through ports 00 and 01 (statu,s
and data, resvectively). You can change this to any consecutive
pair of ports up to OE and OF. This is done by changing the jumper
in Area J. Cut. the existing jumper. Then, install a jumper from
pad 1 to the pad corresponding to the desired port address, as
illustrated below.
r'-
j
.1
'I
j
.2
OQ01
l
,
.3
02,03
I
.4-
04,05
fo.i ~5
06,07
f:
'NiJ
86
08,09
.7
OA,OB
.8
O~OD
.9
OE,OF
3.1 .. 8
Changing ~he Polarity of Vertical Sync Signal
The board is shipped to output an inverted vertical sync signal, as
required by the V2ctor Graphic Mindless Terminal. If you are usiny
a v ideo mon i cor wh ler, requires a non-i nverted vertical sync s iynal,
then cut the j L,;,Jf\per ire Area A from 1 - 2, and ins tall a j umpe I' from
1 - 3.
The compc~it2 S-100 signal MWRITE is produced by the Vector Gra~hic
2-80 CPU board~ In other cOlclputers, it is produced by the front
panel. If your computer does not generate MWRITE, then you will
need it in order to write to m~mory. The Flashwriter II board will
generate it if you place a juoper in area G, from 1 - 2.
3.1.10
Chan9i'~e Polarity of t.he Keyboard Strobe
There are 4 commo~ t;pes of strobes generated by keyboards to
indicate that a key has been depressed, as illustrated below:
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Vector Gr?phic Flashwritor II Board
3-5
-
DATA AVAILABLE AT +
+
--lI-
12
+
~
3
The first type is the one used by the keyboard on the Vector Graphic
Mindless Terminal. Both it and the fourth type require that the key
data be strobed into the Flashwriter keyboard latch on the rising
edge of the strobe .. The Flashwriter II board is shipped to strobe
the data into the latch on the rising edge. On the other hand, if
your keyboard generates the second or third type of strobe, cut the
jumper in Area H.
3.1.11
Using Interrupt Driven Software
If you want the keyboard to generate an interrupt whenever a key is
depressed, put a jumper in Area L from 1 - 2. If this jumper is not
in place, then keyboard data can only be obtained by polling the
status port. (See section 3.2).
3.1.12
Supplying a Keyboard with a Negative Voltage Power Supply
If you have a keyboard which requires a negative voltage power
supply in addition to the +SV, and you are technically oriented,
then there are pads in Area N of the board to install a zener
regulated power supply. The circuit diagram on the left, below,
will be completed if you insert the correct resistor and zener in
Area N, as shown on the right, below.
Rz
Jl-9
AREA
N
ITD
RZ
The zener voltage will depend on the keybard requirements if it is
needed at all, and the resister should be selected to bias the zener
with at least 10 rnA of current in addition to the current required
by the keyboard. For example, with a keyboard requiring 10 rnA of
current at -6V, the zener could be a IN7S2A (S.6V) and the resistor
could be 10/.02 = 500 ohms (470 nominal). The zener power
dissipation would be 60 mw and the resistor dissipation would be 200
Revision 1 J./30/79

3-6 Vector Graphic Flashwriter II Board
mw. Use a 1/2 watt resistor to allow for higher supply voltages.
].1.13
Using a Spare K~y on the Keyboard for Reset
If your keyboard has an extra key not connected to the keyboard
encoder logic, it can be used to reset the system, as an alternate
to the reset key on the front panel. This is not possible with the
Vector Graphic Mindless Terminal. Simply connect the key so that
when it is depressea it grounds pin 11 of J1, the keyboard socket.
See section 3.4.3 for a diagram of J1.
This pin is connected co pin 75 on the bus (PRESET). When the line
is grounded by depressing the key, the jump-on-reset circuit on this
or another board will enable the Monitor PROM on the same board.
Hz Vertical Blanking Signal
Bit 5 of the input sta0us port is low during vertical retrace.
3.2 Programming for the Flashwriter II Board
3.2.1 Vector Graphic Extended Systems Monitor 3 EV-II
By far the most convenient way to use the Flashwriter II board is
through the use of the Vector Graphic Extended Systems Monitor,
Version 3, Option EV-II or CV-II. This program comes on a PROM to
be installed in position 8on the Vector Graphic 12K PROM/RAM board.
The Monitor is NOT automatically included with any order of the
Flashwriter II board, and therefore must be ordered as a separate
item. If you are upgrading a system from a Flashwriter I board, the
Extended System Monitnr used for that board will not work with
Flashwriter II. You must order Monitor 3.
In contrast with earlier Vector Graphic Monitors, the video driver
in Monitor Version 3 allows you to write anywhere on the screen,
either by moving the cursor from the keyboard or entering X,Y
coordinates from an assembly language or BASIC program. (BASIC must
have POKE, as does M.8ASIC provided with Vector Graphic Systems.)
It also allows you to toggle reverse video from program or keyboard,
and offers several lesJ Eignificant additional features. Both
Monitor Version 3 a~0 23rlier versions contain keyboard input
routines. Option EV-II interfaces to parallel keyboards, while
Option CV-II interfaC2s to serial keyboards as on printing
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•.
-----, ---_.~
'~-'~'
Vector Graphic Flashwriter II Board
terminals.
--_.---:'~.- - .----,
3-7
In addition to the video driver, and keyboard input routines, the
Version 3 Monitor offers a wide range of useful utility programs,
including ASCII Dump, Hex Dump, Jump to Micropolis Bootstrap Loader
(0800), Compare Blocks of Memory, Jump to Extension PROM (C400 - the
start of MZOS or a user written PROM), Find Two Bytes, Go To and
Execute, Input from a Port, Jump to Loaded DOS (jumps to the
warmstart location of MZOS or MDOS, whichever is running), Jump to
0000, Move Memory Block, Non-destructive Memory Test, Output to
Port, Accessing Program Memory (for displaying and changing
consecutive addresses), Compute Checksum, Jump to DeOO, Search for
Single Byte, Test Memory, Jump to 2AOO, Wide Screen ASCII Dump,
Exchange Memory Blocks, Keyboard Echo, and Zero or Fill Memory.
These routines are accessed when the Monitor Executive routine is
running, as indicated by the Monitor prompt *.
Version 3 of the Monitor contains several methods of displaying
characters. Although the documentation to the Monitor describes
these, a review here is useful. The basic technique is to call the
video driver (CALL C006) with the desired cnaracter in the A
register. This is sometimes called "sending" a character to the
driver. This is the method used by all Vector Graphic operating
system software such as MDOS and MZOS to display characters. By
itself, this can only be used to display normal alphanumeric
characters, those with codes between 20 and 7F (Hex). (The driver
converts the codes higher than 7F to the corresponding code from 00
to 7F, by changing the 8th bit from 1 to 0.) Then, only the codes
between 20 and 7F are displayed. Any code between 00 and 1F is
interpreted as acommand rather than a character, or if not a valid
command, then ignored.
How then are graphics characters displayed? To get around the above
resrictions in order to print characters outside the range 20 to 7F,
first ?ut the character you want to print in the B register, then
put Hex 05 in the A register, and then call the-video driver at
C006. If the character is from 80 to FF, then it will be displayed
in reverse video if your board is jumpered for reverse video as
shipped. If not jumpered for reverse video and you are using a256
character set, then codes 80 to FF will produce whatever characters
are specified in the character generator PROM (see section 3.1. 1. )
If the character is from 00 to 1F, the corresponding graphics
character will be displayed, or whatever other character is stored
in t~e character PROM if you have created your own character set.

3--8 Vf'~tor Graphic Flashwri ter II Board
:..-~J ,'.? D i·;:'l::l:-~:!j i~~9 __ ._C}?.E..~~~:::::_~ i~ Es Wi tho ut Us i ng the Vecto r Q!:~EQ!:.~
MOf~itl~~ V~(i~~? L~':'l~r
Extende,~ ~f~~:~~s
Qr.-lV<o:(.,
'. ,_ ,', r (' if
you are bypassing the Vector Graphic
driver, or writing your own video
To d:::,Fl~": a.;-r":,, ·c::,·>:'.;:~ :::.:j:'"ie-",,,here on the screen, simply wri te the
cor(~es'(J()fjC:'.::.r:; ,"-SC',I ·~:c::p. ~,nto the appropriate RAM location, using
th~ PAl'!; c, Lr-,' i·'.;',:"'·"c'.:::"[ II board. Unless you have changed the
10'2 d C. i0 t, ~ E. ,'::,~; ;""',< 1'-:.) 3:': a :3 C rib ed in section 3. 1 •2, it is the 2K
block fi~m J0;; ~~~: Since the screen is 80 x 24, the last 128
bytes of th i::::.:: ~ .. " . ." ,- C t: used. Th e fir s t 10 cat ion 0f t his RAM
cor res p0 :~ G S ,_ ,~; ;: '.C':' icC ,':' ;;~ ft - han d cor n e r 0 f the s c r e en, and
sue c e s s i'.I o~:::,_; ;_ e' .: : ", '" CoF! ;} Cr0s s the screen from left to right,
going to the ls~~ 0j~C c~ the next line down at the end of each
line.
If the b03rd 1~ Lsed as shipped, the characters which will be
produced C:I ?c"lc',·\:;;:":;'·'- code are shown on the diagrams on pages 4-1
und 4-2, This jrJ:·:'.;~:·.c, .:::.::l2cial graphics characters which you can
use to b~i~e S~B?hi~ iXl~es such as pictures or large letters. Note
t hat the c: r; E· ; :~ ,:: t: i" (" ;; ;:.: ,) ", Ja to 9 Far ere v e r se vi d eo ve rs ion s 0 f
those frcm 30 ~~ ~F. 3i~ilarily, if you display a character having
a cede from A~ to ?P, ~~ will be the reverse video version of normal
alph6n~rne(lc cj3:3c~e[~ iro~ 20 to 7F. (This assumes that the board
is jurcp~~rej i~,)r ~:,.:I\,:n:;.~ ,>rId·::;:), as shipped.) As explained in 3.1.1.
you may C:c,::,c,i..:c:;, .• , )",': characters to replace those supplied with
the board.,
If you are writing your own Monitor program, including a video
driver; you can if you enoose install this PROM on the Flashwriter
Board. The socket is labelled U42 on the board. If you do this,
you should refer to sections 3.1.3, 3.1.4, and 3.1.5 in order to
make appropriate hardware modifications if necessary.
Produ\c in:L-~eve (se Video
This section sp0c:f'~a]ly covers reverse video, even though it has
been discuSS2L: in pr2c,-~d~nJ sections. Reverse video refers to
displaying a character in black, on a white background. This
section is oaly relev,:;;·,t if the Flashwriter Board is jumpered for
reverse video, as shipped f~om Vector Graphic, rather than for a 256
character set. (See section 3.1.1.)
The easiest way to cause reverse video is to go the Monitor
Executive routi(\8 (l~~ you have the Vector Graphic Monitor Version 3)
by depressing ESC on t'le keyboard. Then depress Control-T (CTRL and
Revision 2 7./7/79