OOOOThe Boston Computer Society
SINCLAIR-TIMEX USER GROUP NEWSLETTER
February 1984
Volume 3 Number 2
Januar-y Meeti ng
Mi gh 1 i gh t m
Because of a surprise snowstorm
the January regular meeting was
cancelled at the last minute.
The message didn't get out to
everyone, though, and an
abbreviated meeting convened in
the small science auditorium
downstairs from our regular
meeting place.
TSIOOO IN TME
OPERATING ROOM
by Robert Douglas
1984
MARCH
1984
MON
TUE
New M
2nd
4
First Q.
Full M
17th
6
Last Q
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A Timex Sinclair 1000 is being
used in Open Heart Surgery Cases
at the University Hospital in
Boston to perform repetitive
calculations of hemodynamic
status. The calculations were
originally performed by hand
until the advent of the
programmable calculator. The
programmable calculator reduced
calculation time dramatically,
but it too had drawbacks. For
example, inputting and
outputting parameters from the
wrong register of the
calculator. With the Timex
Sinclair computer this problem
is eliminated . The TSIOOO can
print out the input parameters
and the calculated parameters
Led by Will Stackman and Jack
Hodgson the meeting consisted of
a demo by Will of the ZX LR8
fast loading program from G
Russel 1 El ectroni cs.
The bulk of the meeting
consisted of a free-wheeling
discussion of the Timex and
Sinclair computer communities.
There was much concern about the
intentions and health of The
Timex Computer Corp.
Although sparsely attended the
meeting was interesting. For
future reference, meeting
cancel 1 ati ons will be announced
on WHDH (850 AH) and WVBF (105.7
FH) .
BU 1000
page 4
The Boston Computer Society ; ■ akr n
cv.ii of personal computers If you re jm.f -rested m
•omputers foi homo, business oi education, come to
The DCS for objt -cUve mformatioi an i supper i He •
3CS is the largest nonprofit personal computer asso¬
ciation m the United States; our goal is run to pro¬
mote any particular brand of compute’ but to help
computer users and people who just wan1 to km ov
what a computer could do foi them
Sign me up for these user/interest groups:
□ Apple/Boston (Apple)
□ Atan User Group
□ Business User Group
□ Consultants & Entrepreneurs Interest Group
□ Database User Group
□ Displaywntei User Group
□ Educational Resource Exchange
□ 80/Boston (TRS-80)
C Family Home User Group
□ Logo User Group
G IBM User Group
G North Star User Group
G Osborne User Group
□ OSI/Boston (Ohio Scientific.)
G Pascal User Group
G PET/CBM/VIC User Group
□ Robotics Interest Group
Sinclair /Timex User Group
G Telecommunications User Group
*** ZX PRO/FILE ***
a 16K+ file manager for the Timex
ZX PRO/FILE is a machine language data base
that gives you tremendous versatility:
*instant access to any file stored in memory
★ files of any size in the same program run
★single or multiple word search capabilities
^ordered file displays
^comprehensive programmable printer functions
A 59 page manual comes with the cassette. In it
are complete instructions, examples, directions
for upgrading to larger memories, modifications,
program listings, and a detailed explanation of
how' the program works. There’s even an intro¬
duction to machine coding for beginners.
ZX PRO/FILE is the best file manager you can
get for your Timex. In fact, users report that it
provides data handling functions found only on
the most sophisticated systems.
Price: just $16.95
Let me send you full specifications. Write to:
Thomas B. Woods
P.O. Box 64, Jefferson, NH 03583
Phone: (603) 586-7734
OOTTe Boston
GO Computer Society
Three Center Plaza
Boston, MA 02108
617-367-8080
Nonprofit
U S. Postage
Paid
Permit 1138
Boston, MA
1 O REM
There are typos and there are
typos. Last month the M/L Group
highlights piece stated
repeatedly that that group meets
on the -first monday of the
month. That's not true. It meets
on the first Wednesday.
We try to be very careful about
typos in this publication.
Especially those in technical
items like data or program
listings. But the way this
letter is put together,
particularly the shortage of
manpower, result in some jobs,
like proof-reading, get less
attention than others. And that
brings me to my second item
here.
We really need some more help
putting this newsletter
together. Particularly we need
help with collecting and editing
the stories (an associate editor
) and someone to help with the
typsetting and "cut and paste"
work of creating the letter (
graphic artists) . This
newsletter is an important
endeavor and we are more
fortunate than other BCS
newsletters in that we have a
strong core of devoted
contributors. Other larger
groups are impresed with the
supports we get. But now we need
a bit more support. If you have
some abilities along these lines
call me.
Lastly, the new BCS office is
now open. It is located at One
Center Plaza, at the other end
of the plaza from the old
office. It is a wonderful
facility and is going to be a
real asset to the Society’s
growth. Stop by and visit.
A final note: Do you know what
the difference is between the
Timex Computer Corp. and a Boy
Scout Troop? The Scouts have
adult supervision.
OThe
O Boston
Computer
y
Q
This newsletter is produced to
inform group members of the
agenda and logistics of future
meetings, as well as to recap
and amplify the information
provided at the meetings. It
also provides a forum for
members and interested parties
to communicate what thay have
learned or developed relating to
Sinclair and Timex computing.
Meetings are open to the public
(non-member admission is *3);
however attendees are encouraged
to join the Boston Computer
Society (BCS) This newsletter
is free to members. Back issues
are one dollar each.
DIRECTIONS TO MEETING: The S-T
User Group meets in the Large
Science Audi ti ori um (Room 8/2/
009) of the University of
Massachusetts, Boston Harbor
Campus. It is located only 3
miles from downtown Boston and
easily accessible by public and
private transportation. From
the north or west, take the
Southeast Expressway to Exit 17.
Turn left onto Columbia Road.
Follow construction signs to get
to Morrissey Boulevard in the
direction of UMASS and the
Kennedy Library. Bear right on
traffic island, get in the right
two lanes, following UMass/
Boston signs. Turn left at the
light into Campus. From the
south, take Morrissey Boulevard
northward to the campus. On the
MBTA, take the Red Line CAshmont
Train) to Columbia Station.
Transfer to the free Uni ✓ er s i t y
shuttl ebus in the T parking lot.
7
piugs 1,2, and 3 into your little
equation and give* you back the
answer, in this case putting it
in the variable X. The values
you pass to the funtion don’t
have to be actual numbers but
can be other variables!
X = FN 2 (M, N, 0)
where M,N, and 0 have been
established earlier in the
program.
;be -following example show a
more practical use of DEF FN. It
goes like thisi
DEF FN 8 ( A, B, C) - < A>B> * < A-B> +B
-<B-C> * (B>C)
This function is quite useful as
a kind of bandpass filter; that
is:
FN S (1 ef t , x , right ) *
left, if XCleftj
X, if 1 ef t<*X<*ri ght
right, if X>right
The function could be used, for
example, in a game program to
keep an object within bounds.
it a also interesting to note
that:
BU 1000 continued
The system consists of the
Si nclair ZX81 computer with 16K
memory, the f S2040 printer and a
Sony Television which has been
adapted to run off 12 volts DC
to meet Hospital Electrical
Safety Codes. The Timex supplied
power supply for the computer
inadequate for our application.
!° * new,one *** designed which
runs coaler and is more
reliable. The computer is left
on constantly to prevent
reloading the program daily
(incidental ly, it has not
crashed in the six months that
it ha* been in u*e) 8
Although the Timex Sinclair
computer is considered a toy by
some when compared to other
larger and more expensive
computers, there are
applications for it where large
computing power is not required.
JDur system, which cost under
*200, is thousands of dol 1 ars
cheaper than current models
disigned for this application.
FN S (X, Y, Y) “Maximum of (X.Y)
and *
FN S (X, X, Y) -Minimum of (X,Y>.
[Robert Douglas is a Clinical
Engineer with the Anesthesia
Department of the Uni versi ty
Hospi tal , Boston Uni versi ty
Medical Center!
The Sinclair Timex User Group
M/C GROUP HIGHLIGHTS
Sue Mahoney
Di rector
c/o BCS Office
or 203-755-2699
Jack Hodgson
Publ isher /Editor
P.0. Box 526
Cambridge, MA 02238
617-354-7899
John Kemeny
User Group Correspondent
284 Great Road, Apt. D5
Acton, MA 01720
Beth Elliot
Group Librarian
c/o Sinclair Research
50 Staniford Street
Boston, MA 02114
617-742-4826
Allan Cohen
Meeting Coordinator
617-961-3453
Jeff Parker
Advertising Manager
c/o P0 Box 526
Cambridge, MA 02238
617-354-7899
The Sinclair Timex Newsletter is
published monthly by the
Sinclair Timex User Group of the
Boston Computer Society.
Membership in the BCS is »24 per
year which includes a
subscription to its magazine
"The Computer Updata" and
subscription to two of its group
newsletters (such as this one).
Advertising space is available
in this publication on a
limited, first come first served
basis. The rate is *60 per
quarter page. At this time no
other ad sires are available.
c°r detailed rate and discount
information contact the
Advertising Manager or the
Pud 1 i sher .
The machine code sub-group met,
as usual, on the first Wednesday
(NOT MONDAY AS STATED HERE LAST
MONTH) at Itek Optical Systems
in Lexington. Attendance
continues to grow in size and
enthusi asm.
The meeting was opened with a
brief presentation by Jack
Hodgson of the Zeus Assembler
package for the TS2068 Color
Computer. The Zeus allows the m
/c programmer to enter their
code with mnemonics and symolic
jump and call addresses. "This
is a terrific tool. It
simplifies the coding process by
a significant factor. I don’t
know how I ever managed without
it," remarked Hodgson
enthusiastically. The Zeus
Assembler is from Soft Sync.
Dave Wood showed the group his
newly arrived Compusa 51/4 inch
floppy disk system for the 1000/
1500 computers. "I really love
it." He said. The drive loads
and saves programs and data much
faster than the standard
cassette unit. Although Dave’s
drive was ordered in October and
just arrived recently. It is
believed that Compusa is now
shipping the drives promptly.
The group viewed a demo of G.
Russell’s ZX LR8 fast loading
program. ZX LR8 will load, from
cassette, 16K in approx. 60
seconds.
Group leader Bob Heath plugged
the special presentations coming
up in March (see elsewhere in
this letter), and urged members
to participate in the Dazy
Project .
The Machine Language and
Hardware Design Sub-Group meets
on the first Wednesday of the
month at Itek Optical in
Lexington. For details and
directions call Bob Heath days
at 276-2424.
ports available -for IN use only
(using Al).
INTERRUPTS
It should be noted that the Z80
interrupt system is pretty much
tied up by the Timex operating
system in order to maintain the
TV display. It might be
possible to utilize mode 2
interrupts by operating
exclusively in FAST. In this
case, the I register, normally
used for TV character
generation, could be used to
vector the interrupt out of the
ROH and into the user’s
application routine. An
additional complication is
introduced by the fact that the
A6 address line is tied to the
Z80 INT line. To the best of my
knowledge, no one has made use
of interrupts on the Timex
computer.
I MS I DEE I NFO
from zilog
On March 7 the Machine Code
Group will host Mitch Russo of
Nova Sales at their regular
meeting (first WEDNESDAY). Mitch
owns a ZX81 . That in itself may
not seem too interesting, BUT he
bought it so he’d have something
to run his emulator on. You see
Mitch is the local
representati ve for Zilog and in
addition to promoting sales of
their products he is an
enthusiast of the peripherals
the Z80 will support. Over the
years he’s built a sizable home¬
made system.
So, if you want to find out what
an emulator is and hear lots
more about the inner workings of
the Z80 microprocessor that’s at
the heart of all the Timex
Sinclair computers, come join
with us on the 7th.
Mitch has made one request: he
asks that each of us bring to
the meeting a sheet of paper
describing some Z80 software or
hardware project that we’ve
either completed or are working
on.
For details on last month’s
meeting and info about attending
see the machine code group
highlights elsewhere in this
newsl etter .
DEF Frlvl COMMAND
OIM THE TS2068
by John Kemeny
The TS2068 has a feature that
allows users to define one line
functions. If you have a math
formula that is used many times
in the program you can program
it into a ’function’ and ’plug’
any values you choose into it.
For example if you were going to
multiply two numbers together
and then divide the result by a
third the formula might look
like this:
(A*B)/C.
You turn this into a function by
using the DEF FN (beneath the
"1" key), it comes out looking
like this:
DEF FN Z(A,B,C)»(A*B)/C.
You’ve now created a function
called Z. When you go to use
this function you ’pass’ the
values for A,B, and C by putting
them in parenthesis following
the function name. For example
X" FN Z (1,2,3). The computer
and 1 ab*l *ach on* to avoid
interchanging the values. The
physician can instantly
determine whether the readings
are valid and take appropriate
action.
The program instructs the
physician to enter the patient's
weight, height, cardiac output,
heart rate, and blood pressure
measurements (MPAP, PCWP, MAP,
and CVP) . It then cal cul ates
body surface area, stroke
volume, stroke index, cardiac
index, systemic and pulmonary
resistance, right and left heart
stroke work index , and the ratio
of left and right heart
resistance. These calculated
parameters give the physician
valuable data on the patient's
condition and what mode of
therapy to administer. The use
of the computer allows the
physician to determine these
parameter* rapidly and to
interpret them before they
become obsolete. Shown below is
what is displayed on the
television at the start of the
program to instruct the
physician on how to enter each
of the input parameters. The
program also performs a self
test on itself to insure that it
has loaded properly, and prints
out that it has passed.
SELF T
E5T OK
ENTER
200
WEIGHT IN LBS.,
NIT ENTER
ENTER
70
HEIGHT IN INCHES
, H IT ENTER
ENTER
UHRCTfl C U UT P UT }
HIT ENTER
ENTER-
60
HEART RATE, HIT
ENTER
ENTER
15
MPAP , HIT ENTER
ENTER
PCWP, HIT ENTER
10
: i7t
MAP, HIT ENTER
CUP, HIT ENTER
Shown below are the computed
parameters along with the input
which are printed out on both
the television and the printer .
The patient’s name can be filled
in along with the date and time.
Each printout is numbered in
consectuti v* order at the top
left hand corner next to the
patient' * name. The weight and
height have to be entered only
once for each patient and are
stored in the program until the
end of the case.
#1 PATIENT DATE TIME
WEIGHT : 200
HEIGHT : 70
C . O . : 5.2
H.R. : 60
MPAP : 15
PGUP : 10
MAP : 80
CUP : 5
SURFACE AREA =2.1
STROKE U GLUME = 88.3
STROKE INDEX = 39.9
CARDIAC INDEX = 2.4-
SYS UAS RES IS = 1200
PUL UAS RES IS = 80
BU 1000
page 7
This
#£*IMD OUT " m OIM
THE TIMEX COMPUTER
by Dave Wood
OVERVIEW OF ZSO I/O
There are three types of input/
output (I/O) instructions
available on the Z80
mi croprocessor inside your
Timex. All generate a 16-bit
address, providing a potential
o-f 65536 I/O ports.
1. Accumulator I/O CIN A, <n)
OUT (n) , AD. The byte "n"
provides the lower 8 bits on the
address bus, and the A register
provides the high order 8 bits.
The data is then read into the A
register from the data bus (IN)
or onto the data bus -from the A
register (OUT) . Note in the use
o-f OUT, that the A register
plays a dual role. The output
byte al so -forms the hi gh address
byte, limiting practical
applications to 8— bit port
addresses.
2. General register I/O CIN r, <
C) OUT (C) , r 3 . The C regi ster
provides the lower 8 bits on the
address bus, and the B register
provides the upper 8 bits. The
data is read into or out o-f the
specified regi ster , r .
3. Block I/O. Block I/O
instructions are available to
move data between the port
addresses by the BC regi ster and
the memory location pointed to
by the HL register.
I/O RESTRICTIONS ON THE TIMEX
The number of I/O ports actual 1 y
avai lable to machine language
programmers on the Timex is
quite limited. In general the
lower three bits (AO, Al, A2)
are reserved for control of the
computer. Furthermore, the high
order 8 bits may contain random
data, so must be ignored.
1 i mi ts the user to 31
uncontested I/O ports.
Bit AO is used to control the
keyboard read as well as
cassette input and output. If
AO is low (logical 0), then an
IN command will activate
keyboard scan, read the cassette
input line, and set the cassette
output line low. An OUT command
with AO high sets the cassette
output high. TV output is on
the same si gnal line as the
cassette, so these IN/OUT
operations will flash on the
display.
Bit Al (in combination with AO)
is used to control the SLOW/FAST
model it enabl es/di sabl es
generation of the non-maskable
interrupt (NMI) every l/60th
second . OUT with the two lower
bits containing 10 activates the
NMI generator for the SLOW mode.
OUT with the lower bits
containing 01 turns off NMI and
the computer runs in the FAST
mode. If both bits are zero (00
) , then the system will crash.
Bit A2 is used to control the
Timex Printer . Bit A2 low will
enable the printer.
SUMMARY OF 1/0 LIMITATIONS
For unrestricted input/output,
there are 31 ports available.
Bi ts A0-A2 must be high to not
impact the system operation,
other than toggl ing the cassette
and TV signal lines. Thus the
available ports are (in hex ) 07,
OF, 17, IF, ... , E7 , EF, F7.
Port FF is used for writing to
the tape cassette. If the Timex
printer is not being used, then
32 more ports are available,
making use of the A2 line.
Furthermore, since OUT is the
most restrictive (due to the NMI
setting) there are 32 addi ti onal
continued next page
