Sinclair ZX INTERFACE 1 User manual

.

ZX INTERFACE 1
and
ZX MICRODRIVE
Designed and prepared by
Cambridge Communication Limited
Note
The names ZX Microdrive and ZX Interface 1 are trademarks of
Sinclair Research Limited
Stanhope Road
Camberley
SlNrey
GU15 3PS
Tel: Camberley [phone]
First Edition 1983
@Sinclair Research Limited
Front cover illustration by John Harris of Young Artists

THE 2X INTERFACE 1.. .
incorporates the three functions of Microdrive controller, local area network
and RS232 Interface. Connect it to your Spectrum and you can control up
to eight Microdrives, communicate with other computers and drive a wide
range of printers.
THE 2X MICRODRIVE.. .
gives you fast Access to a large memory. Each Microdrive can hold up to
100K bytes using a single interchangeable cartridge.
THIS MANUAL . . .
introduces the idea of using BASIC as an operating system as well as a
programming language. This way, BASIC can be used to set up
communication links, to send and receive data along them and to manipulate
files. This adds enormously to its power to perform tasks in which:
- data is stored and retrieved,
- data and programs are sent to peripherals,
- communication links are established with other Spectrum computers or
with other types of computer.
The combined use of BASIC as an operating system and a programming
language gives it a power and flexibility, and also an ease of use, to be
found in few larger computers.
You should read the chapters on the Microdrive even if you have not bought
one, since they introduce various concepts (about channels and .Weams and
their use) which you will need to understand.
This manual should only be read after you have familiarised yourself with the
ZX Spectrum Introduction booklet and with chapters 1 to 22 of the BASIC
programming manual.

Contents
Chapter 1 Setting up your 2X Interface 1 5
Chapter 2 Setting up your Microdrive 9
handling cartridges
protecting programs and data stored in cartridges
the cartridge lifespan
Chapter 3 Starting with your Microdrive
auto-run
the catalogue
loading programs
15
Chapter 4 Programs and the Microdrive
saving, verifying, loading and merging programs
erasing programs
formatting and naming blank cartridges
setting up your own auto-run facility
17
Chapter 5
Chapter 6
Data. channels and streams
Data and the Microdrive
opening and naming a data file
entering data
closing a file
reading back from a file
notes on PRINT and INPUT -separators
- changing weam
- setting colours
reading the file catalogue
protecting a file
extending a file
Chapter 7 The Local Area Network
setting up a network
programs and the network
data and the network
broadcasting
21
23
29

Chapter 8
Chapter 9
Appendix 1
Appendix 2
Appendix 3
Appendix 4
Appendix 5
Appendix 6
Index
Using the RS232 Interface
connecting peripherals to the RS232 Interface
t and b channels
the t channel
the b channel
sending control codes
35
The MOVE statement
the printer .wver program
The net game
System variables
Microdrive and network channels
RS232 connections
Rep&S
The extended BASIC
39
41
45
47
49
51
55
59

Setting up your ZX Interface1
Unpacking the ZX Interface 1 you will have found:
- this booklet,
- the Interface itself (with two captive screws on the underside),
- a ribbon cable about &ms long (for connecting the Interface to a
Microdrivel,
- a lead with a jack plug at either end (for setting up a network).
To attach the Interface to your computer you should:
1. Unplug the computer.
2. Disconnect the computer from its peripherals.
3. Using a Posidrive screwdriver remove the two screws on the underside
of the computer, as shown in the diagram below. (You will only
need these screws again if you later disconnect the Interface from
the computer.)
I
10
cl
I

4. Push the Interface edge connector firmly into the socket at the back
of the computer.
5. Screw the Interface to the underside of the computer using the two
captive screws supplied.
6

The diagram below shows what the various sockets on the Interface are for.
You can now either:
- set up a Microdrive see page 9,
or
- set up a network see page 29,
or
- connect the Interface to an RS232 peripheral see page 35.
7

Chapter 2
Setting up your Microdrive
Unpacking the Microdrive you will have found:
- the Microdrive itself,
- an electrical connector (for connecting this Microdrive to another one),
- a prerecorded demonstration cartridge.
To attach the Microdrive to the Interface, push one end of the ribbon cable
(supplied with the Interface) firmly into the socket on the side of the
Interface. Then push the other end of the cable into the socket in the side
of the Microdrive.

If you have several Microdrives, the second one can be connected to the
first as follows.
1. Disconnect the Microdrive from the computer.
2. Turn both Microdrives upside down. You will find that each has a bracket
screwed to the underside.
3. Unscrew and remove both brackets.
4. Turn the Microdrives the right way up again.
5. Push one of the electrical connectors firmly into the socket on the side of
one of your Microdrives (as shown belowl.
6. Push the second Microdrive up against the first, so that the other end of
the electrical connector pushes into the socket on the side of the second
Microdrive.

7. Carefully turning the Microdrives over again, screw back one of the two
brackets - but this time so that it links up the two Microdrives. (The
remaining electrical connector, bracket and screws can now be kept for
linking up a further Microdrive.)
8. Turn the Microdrives the right way up again, and reconnect the one on
the right-hand end to the computer.
Note that the Microdrive nearest the computer is always known as
Microdrive 1, and the next along is Microdrive 2, and so on.
Notice also that on the front of each Microdrive there is a light.
This will come on whenever the Microdrive is running.

Handling cartridges
Every cartridge c~nw in a protective box; and should always be kept in its
box when not in we.
When you take a cartridge out of its box (being careful not to touch the tape
itself) you will see that it has a label on the top and another on the side.
Push the cartridge firmly into the slot in the front of the Microdrive, making
sure that the label on the side faces upwards. This will leave the top of the
cartridge projecting by about %cm. The Microdrive and cartridge are now ready
to be used.
When you have finished using the cartridge, pull it carefully out of the
Microdrive, and replace it immediately in its box. But remember.. .
NEVER TAKE THE CARTRIDGE OUT OF THE
MICRODRIVE WHILE THE MICRODRIVE LIGHT IS ON.
NEVER SWITCH THE POWER ON OR OFF WHILE A
CARTRIDGE IS IN THE MICRODRIVE.
12

Protecting programs and data stored in cartridges
If you wish to protect the programs and data stored in a cartridge (that is,
prevent them from being over-written or erased) then you should snap off the
plastic tab from the side of the cartridge, as shown below.
(As with a cassette, you can reverse this effect by sticking vxne tape OWI
the place where the tab has been removed.)
The cartridge lifespan
Microdrive cartridges will not last forever, and will eventually need to be
replaced. The symptom of an ageing cartridge is that the computer will take
longer and longer to find a program or file before loading it. So it is a good
idea to keep back-up copies of important programs and files either on another
cartridge, or on a carsette.
13

Starting with your Microdrive
Auto-run
Now that you have set up your ZX Interface 1 and your Microdrive, you
will want to know what programs are waiting for you on the demonstration
cartridge. So. insert the cartridge into the Microdrive (or, if you have several
Microdrives, into Microdrive 1). and enter:
NEW
followed by:
RUN (and ENTER)
This will automatically load and run the first program on the cartridge. When
you have finished watching this program, read on.
The catalogue
To find out what other programs are stored in the demonstration cartridge,
enter the CAT&ague statement:
CAT 1
I
1 identifies the number of
the Microdrive you are using
In about seven seconds the television screen will display:
- the name of the cartridge,
- an alphabetical catalogue of the names of all the files stored in
the cartridge,
- the amount of memory left in the cartridge (in kilobytes).
15

Loading programs
The next thing to do is LOAD whichever program you would like to st!t! next.
So, first choose your program, then enter:
After a short pause, the screen will display the OK message (though not the
name of the program). You can now run the program.

Programs and the Microdrive
Saving, verifying, loading and merging programs
In the ZX Spectrum Introduction booklet you found out how to SAVE
programs on a cassette tape. Saving programs in cartridges is iust as easy. Here
again is a program called Squares, much like the one in the Introduction
booklet:
10 REM Squares
20 FOR n=l TO I0
30 PRlNTn,n++n
40 NEXT n
To SAVE this on a cassette tape you would enter:
SAVE “Squares”
To SAVE it in the cartridge in Microdrive 1, you enter instead:
SAVE *“m”;l :“Squares”
After about six seconds the border will flash, and the program will be saved.
Try it and see.
(The names of programs stored in a cartridge, like those of programs stored on
a cassette tape, can be up to ten characters long.)
As you would expect, you can now check that the program has been saved by
entering:
VERIFY W”m”;l:“Squares”
The screen will then display the OK message.
You can now LOAD the program Squares by entering:
NEW
followed by:
LOAD *“m”;l ;“Squares”
then:
ENTER
17

Next, to make the program run automatically, try entering:
SAVE Y”m”;l;“Squarer 2” LINE 10
then:
NEW
and then:
LOAD++“m”;l:“Squares 2”
Programs can also be merged using a Microdrive. Enter:
NEW
followed by:
1bB REM more Squares
1lQ FOR n=ll TO 20
120 PRINT n,n*n
13Q NEXT n
And now enter:
MERGE *“m”;l;“Squares”
then:
ENTER
The program Squares will be added to the listing.
In short, as you have probably already realised, all the syntax used within
an ordinary cassette interface (explained in chapter 20 of the BASIC
programming manual) applies also to the Microdrive.
Erasing programs
Suppose you have just finished with the program Squares. To erase it, enter:
ERASE “m”;l;“Squares”
(As before “m”;l simply indicates which Microdrive you are using.)
During the ERASE statement the border will flash,
If you BREAK while saving a program then you will have an unclosed file
in the cartridge. You cannot LOAD an unclosed file, and an attempt to do so
will give the report file not found. The ERASE Statement can delete an
unclosed file, but will take about thirty seconds to do so because the compute!
checks the cartridge several times to make sure that the file has no end.
IS