Related Manuals for Sinclair ZX81
Summary of Contents for Sinclair ZX81
- Page 1 ZXpand Expansion Interface For the Sinclair ZX81 © 2011 Charlie Robson/EightyBits for RWAP Software MANUAL Manual Update 1.2 (September 2014) © RWAP Software www.rwapsoftware.co.uk...
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Page 2: Table Of Contents
ZXpand Manual TABLE OF CONTENTS TABLE OF CONTENTS ....................... 2 NOTICE ..........................3 OVERVIEW .......................... 4 COMPATIBILITY ........................4 WHAT DO I NEED ........................ 5 GETTING STARTED......................5 COMMAND REFERENCE ....................5 CONFIG..........................6 CAT ........................... 7 LOAD ..........................8 SAVE .......................... -
Page 3: Notice
RWAP Software. The manual has been written specifically for users of the ZXpand Expansion Interface for the Sinclair ZX81 home computer. -
Page 4: Overview
ZX81s which have been modified in some way and so we cannot guarantee that the ZXpand will work in all circumstances. The ZXpand can also be adapted to work with the Sinclair ZX80 computer, although you will need to use a replacement ROM inside the ZX80 itself (see below). -
Page 5: What Do I Need
You may want to organise your files on the card by creating directories, again 8 characters maximum in the name, and putting a few files in each. The ZX81 was never designed to make use of a file system and this should make finding the file you want much easier. -
Page 6: Config
ZXpand Manual CONFIG CONFIG "x" CONFIG "x=y" (Press shift-G in K mode – replaces ‘LLIST’ command) The CONFIG command is the main method of communicating with and configuring the ZXpand interface. As the working of some programs and commands is affected by how the interface is set up, this will be dealt with first. -
Page 7: Cat
ZXpand Manual CAT "" CAT "directory" (Press Z in K mode - replaces ‘COPY’ command) It is sometimes useful to know what files are available on the card. The CAT command will do this. Providing an empty string will list the content of the current working directory (CWD). To list the content of directories relative to this then you must specify the path as you might for a DOS based system. -
Page 8: Load
ZXpand Manual LOAD LOAD "filename" LOAD "filename;X" LOAD "filename;address" LOAD "" LOAD will take data from the specified filename on the card and place it in memory. The basic LOAD command will work just as you expect. Specifying an empty name will invoke the tape loader as normal to allow you to load a program from cassette. -
Page 9: Save
AUTOBOOT The ZXpand can be configured to automatically run a program called ‘menu.p’ when the ZX81 is switched on or reset. Nominally the ZXpand is set to autoboot when the SHIFT key is pressed during power on. -
Page 10: The Reset Button
A short tap will reset the ZX81 only. The green LED will flash. HARD RESET A longer press, approximately 1.5 seconds, will reset the ZX81 and the interface controller. The green and red LEDs will flash. FACTORY RESET A 5+ second press of the button will restore the content of the EEPROM to its factory default. -
Page 11: Information For Programmers
ZXpand Manual INFORMATION FOR PROGRAMMERS The interface lives on I/O port 7 which is fully decoded. Bits 15...13 of the address bus are latched when port 7 is accessed and then used as a channel number in order to perform different tasks. Therefore the only valid IO instructions for accessing the port are: out (c),a in a,(C) -
Page 12: Firmware Updates
0 represents whether a card is present… Alternatively you can call a function at 8190 ($1ffe) to retrieve the value. The ZX81 firmware source is available for instructional use. Any suggestions for improvements/bug reports will be welcomed. -
Page 13: Hardware
ZXpand Manual HARDWARE THE JOYSTICK PADS The above image shows the break-out pad assignments. The inputs have built-in pull-ups and are active low. A joystick break-out board will be available in the near future. The reset pin is not enabled in the current firmware. Here is an overview of the various components and pads on the ZXpand. -
Page 14: Zx80 Compatibility
Having modified the ZXpand, you may still use it with the ZX81 by removing the small plastic jumper (just remove it from the two pins you soldered to the board). The new memory decoder GAL works for both systems, so that is all you need to do. - Page 15 .80, these are identical in operation and so any .80 files should be renamed to have the .O extension. As with the ZX81 firmware, the LOAD and SAVE commands will invoke the tape routines when entered without a filename or an empty string “”.
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Page 16: Error Codes
ZXpand Manual ERROR CODES The interface can report the following errors. They are shown in inverse video to distinguish them from standard system report codes. Disk error - the card file system may be damaged Internal error - the filing system data structures are inconsistent Not ready - the card is not responding or no card is present File not found - no such file exists No path - no such directory exists...