Radio Shack System 80 User manual

mAnuAL

This manual is aguide that helps you to get familiar with the System 80 in the
quickest manner. It helps you to set up the system and to operate it efficiently. An overview
of the System 80 is provided so that you will find no difficulty in understanding and
expanding your system. Moreover, higher level computer users will find the technical
information mthe APPENDIX very useful. In case you have any problem or any suggestion
don thesitate to contact your local dealers. Welcome to the exciting world of personal
computing. ^
PREFACE
You are welcome !

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CONTENTS Pa* JflBLE QpCOnTEflTT
1. Introduction 3
2. Power On Preparation 5
3. Video Display format 6
4. Keyboard and Cassette 7
5. Program loading g
6. Program Saving . . . ..10
7. Second Cassette Recorder ..,,....,,.,, 11
8. System Reset 12
9. Software ,12
APPENDIX
A. Technical specifications
B. Memory map and I/O map
C. ASCI Itable

The design philosophy of the System 80 Is like that of most other general
purpose computer systems, and has great expansion capability. The main unit (EG3003/4)
contains aCentral Processing Unit, I/O devices and amass storage device. These are the Z80
CPU, akeyboard, avideo interface and aresident cassette recorder. The EG 3003 has
resident 16 Kilobytes of RAM (Random Access Memory) for user's program storage, while
the EG3004 has only 4K. The system has avideo interface and an RF modulator to
display the information on aVDU or aTV,
inTRODUCTIOn
Fig, 1.1

Beside the hardware configuration described, the System 80 has apowerful
resident EXTENDED BASIC Interpreter which is compatible with that of TRS-80 Level II
BASIC.
An optional S-100 bus expansion box is designed to be connected to
main unit. More peripherals can then be linked to the system by plugging their standard
interface cards into the S-100 bus mother-board. S-100 bus is now astandard in the micro
computer industry, especially for computers using 8080 or Z-80 CPUs,
TV OR VDU
TELEPHONE MODEM
EXPANDER
/
r
.. ,/
LiUJj/
ADDITIONAL
RAM
RS-232-C
SERIAL PORT &> ^
This is my family I
4

The System 80 is ready to operate rrriedietely after unpacking from the
carton box. However, the user shouid adhere to the following procedures.
aEnsure that the power switch is in the 'off position.
bCheck whether the AC voltage labelled on the power supply unit is the same as that of
your country.
CConnect the power plug to apower line socket.
dConnect aVoeo Display Unit to the system. The Unit can either be an ordinary TV
set or avideo monitor.
eE-nwe that the 'Video Cut' switch at the back panel sat the out position. The
display format wil be 64 characters/line.
Turn on the power of the display unit *irst, then the System 80.
gAmessage 'READY?' will be displayed on the top left corner of the display.
hI* no '9E- ADY' message is displayed, go to step (a) and check again.
iAfter the READY?' message appears, the user should hit the NEW LINE key, then
another 'READY' message should appear on tie bottom left corr-er of tne display
jNow, the System is at the Active Command level. You can type in commands to get
the computer to work for you. Please refer to the Programming Manual for all the
Active Commands available.
kIf you want to have another display *ormat, please read the next section.
NOTE: If the power switch is turned off for any reason, the user shouid wait at least 15
seconds before turning the power switch on again,
power on
PREPARATIOD
OFF
~~^
TV
or X
N4DISHTQPI
OfSJ
NEW LINE
*«»—*!
r
hi
b

3.1 FORMAT SELECTION
The System 80 allows two kinds of display formats, that Is, (1), 64 characters
per line; (2) 32 characters per line. The purpose of the latter is to permit an enlarged
and clear character display when atelevision set is used,
3.2 64 CHARACTERS/LINE FORMAT
The 64 characters per line format is selected whenever the computer is turned on and
the VIDEO CUT button is off. The user may select 32 characters per line by pressing
the VIDEO CUT button,
3.3 32 CHARACTERS/LINE FORMAT
a) Press the VIDEO CUT button on the back panel.
b) Press the PAGE button on the front panel to read either the left half or the right
half of the text on the display.
3.4 SPACE INSERTION
Aspace can be inserted automatically between characters by typing in
PRINT CHR$(23) This mode will be reset by NEW or CLS command.
VIDEO DI/PLflY
FORfTlfiT
64 characters
per fine
VIDEO CUT
32 characters
per line
i
VIDEO
'That's better !'
ON
rPAGE CUT
i)

The keyboard acts as aman-machine interface, while the cassette is used for mass
storage of programs and data.
4.1 Special Function Keys
PAGE -select page for display (refer to previous section).
Fl —isolate the cassette from the control of the computer during winding and rewind-
ing and allow manual cassette motor control.
BREAK -break arunning program and return to the Active Command Level.
NEWLINE -enter aline of command or data into the computer.
BACKSPACE —cancel the character previously typed.
ESC -the display echoes afsign which is an exponent sign used by the System.
CTL -move the cursor to the beginning of the next line.
SH IFT/CTL/I -tab function; move the cursor 8spaces to the right.
SHIFT/CTL/Y -same as print CHR${23). See section 3.4
SHIFT/BACKSPACE -delete line,
4.2 Cassette Recorder
The cassette recorder is ahigh fidelity audio recorder. It has six piano keys and a
3-digtt counter. The keys function the same as those of anormal recorder. The user should
take the advantage of the counter for fast program locating.
Program loading and saving will be discussed in detail in next section.
KEVBOflRD 6
CPJ/ETTE
PACE Fl CASSETTE RECORDER
POWER
CONTROL
SHIFT
TAPE COUNTER
SPACEBAR BREAK. BACKSPACE NEWLINE SHIFT RECORD REWIND fF PLAY STOP/EJECT PAUSE COVER

Programs are stored on the cassette tapes in the form of magnetic signals. If the user
wants his Computer to do acertain job, he should write the program, save it onto acassette
tape and then reload the program into the system at any time he wants. He may also buy
any TRS80 Level II Basic compatible tapes from the computer market, then load and run
them. The cassette interface is designed to accept awide range of input signal levels,
therefore, no volume adjustment is required.
Now, please follow the procedures below and try to load the demonstration programs
supplied with your System.
5.1 Loading aprogram from the resident cassette (cassette no. 1)
a. Insert acassette into the recorder.
b. CIose thecover of therecorder.
C. Rewind the tape if necessary, (see section 5.2)
d. If you know where is the program located, wind the tape until the counter
indicates the position of the program's beginning.
e. Type in CLOAD# -1 r"N" (where Nrepresents the name of the program) or, type
in CLOAD. The former command tells the computer to search for the suitably
named file, while the second command will only load the first file encountered.
f. Press the PLAY key on the cassette drive.
g. HittheNEWLINEkey.
At this point, the computer starts searching for the program mentioned in the CLOAD
command; once it is found, two asterisks will appear at the top right corner of the display,
the one on the right will be flashing from time to time indicating the program is loading, A
READY message will appear once the loading has been completed.
5.2 Rewinding Procedure
a) Check if the power switch of the computer is turned ON.
b) Press the F1 key (the red light labelled CASSETTE RECORDER should be on also).
c) Press the REWI NDbutton on the cassette drive.
d) Wait till rewinding stops.
e) Press the STOP/EJECT button to stop all operations physically.
f) Reset the cassette counter to OCX).
g) Turn off the F1 button.
PROGRRfTl
LOflDinG
ON REWINDING
REW
SlOP/fJECI
OFF
.:
F1
**
CLflM'JM/'tf
PLAY
m
NEW LINE
8

5.3 Checking aProgram
a) Read the CLOAD command (section 1.5 mthe BASIC Manual.)
b) Rewind the cassette tape to the starting point of the program.
c) Press the PLAY button on the cassette drive,
d) Type mthe command CLOAD? from the keyboard.
e) Hit the NEW LINE key.
Once the computer finds the program, two asterisks will appear on the top right corner
of the display, the one on the right will be flashing if comparison is successful AREADY
message will appear if the comparison has been completed. Otherwise, the word BAD will be
displayed.
i
PLAY
cioao?
**
or
BAD
NEW LINE
5.4 Listing and Executing aProgram
a) Read the LIST and RUN commands (sections 1.9 and 1.11 in the BASIC
Manual).
b) Type in LIST and hit the NEW LINE key (The entire program will be listed on the
display).
c) Type in RUN and hit the NEW LINE key (The computer starts executing the
program).
[new lineJ
NEW LINE
WARNING :CASSETTE LOADING
Although the cassette interface circuit can tolerate wide range of input signal level,
sometimes, loading error may occur. The reason is that so many software houses produce
TRS-80 compatible tapes and their quality may differ a lot The only solution is to do a
backup for yourself and use the backup copy for future loading.
The backup procedure should be: —
0) Put the TRS-80 compatible tape into second cassette.
(2) Connect the second cassette to the computer.
(3) Use CLOAD #—2, 'f command to load the program into memory.
(4) Try to adjust the second cassette volume if loading fails,
(5) If the program is successfully loaded, save it onto ablank tape with cassette #1
.