ZX81 Emulator

Welcome to the ZX81 EMULATOR v3.0 readme file.

ZX81 EMULATOR v1.0 - 3.0 is (c) Martijn Groen 1997-2001

Many thanks and credits to Johan Koelman for supplying me with  some nice TAP files. Also, Many thanks and credits to Robert van der Veeke for lending me his ZX81 ROM disassambly and other useful things. Much more thanks and credits to Edwin Blink for  supplying me with information about B-DOS and the HD-load and DALLAS clock routines and Comet 1.8

System requirements:

* B-DOS (v1.7p or higher)
* Z-80B 6 Mhz processor or higher recommended
* 256 KB RAM required
* B-DOS: harddisk with at least 1 available record
* 3 joysticks (Triple joystick interface splitter needed)
* DALLAS & Sambus clock supported
* First printer port supported

To load the Emulator, type LOAD "SAM81", Return.

Use LOAD "" to go to the fileselector screen. The current date &time are displayed in the top-right corner if you own a Dallas/Sambus clock. F1/F2 = directory of disk in drive 1 / current  harddisk record. Only files which have a *.T (SAMDisk or a.TAP  (MS-DOS disk) and *.P extension will be displayed. If an error  occurs, the border will flash for approx. three seconds.

Notice that LOAD "1" and LOAD "2" automatically display the directory of drive 1 / current harddisk record.

Use LOAD "3" to enter the C/DVD-ROM browser (needs 512k SAM). See on-screen instructions for navigating through C/DVD-ROMS. Only *.TAP and *.P files will be displayed.

To save a TAP file to drive 1 / current harddisk record use,  SAVE "1" / SAVE "2". Press Return to use the last used name or  type a different name. F9 returns to the Emulator. To save to
default drive, use SAVE "any name" (not SAVE "").

Selecting a record: press key 'M' followed by the record number.Now hold down 'CAPS' key and press Return. If an invalid record is selected then you'll get an error message: 'B'

Input devices in fileselector screen:

* key 'm' = Mouse, Left button loads a file, Right button returns to the Emulator.
* key 'c' = Cursor keys, Space loads a file.
* key 'f' = First joystick, fire button loads a file.
* key 's' = Second joystick, joystick splitter needed
* key 't' = Third joystick, joystick splitter needed.(Thanks Edwin Blink)
* F9 = return to the Emulator.
* NMI button = return to the Emulator.

Keys inside Emulator:

You may use the - + = " ; : , . Delete, Edit and Cursor keys  like in SAM BASIC.

* Control key = Shift + Return
* Inverse key = Shift + 9
* Escape key  = SAM BASIC (GOTO 1 returns to Emulator).
* F0 = Return
* F1 = display help screen, F1 again = display normal screen
* F2 = inverse palette
* F3 = toggle between slow/fast mode
* F4 = slow down Emulator (5 steps possible)
* F5 = standard speed for Emulator
* F6 = speed up Emulator  (5 steps possible)
* F7 = make screen snapshot
* F8 = enter floppy/HD file selector (same as LOAD "1/2")
* F9 = enter C/DVD-ROM browser (same as LOAD "3")

Resetting ZX81 Emulator:

* Use PRINT / RANDOMIZE USR 0 or,
* Hold down TAB key, then Escape or press NMI button.

COPY command: this command is fully emulated.

LPRINT command: after the printer buffer has been copied to the printer an automatic line feed will occur.

Your own printer control code can be poked at addres 40008.  Poke addres 40008 with X,a,a,etc. X = nr. of bytes to be poked, followed by the control code bytes. Upto 32 bytes can be poked.

Notice that a 8-pin graphics mode must be selected and the two  bytes after the graphics control code must be 0 and 1. Your printer must be on and on-line before the Emulator is loaded.

Versions 1.8 and higher allow you to load from and save to any  record on a master or slave harddisk (B-DOS v1.3 or higher).

TAP utilities:

* Prog->Tap allows you load .P files from (MS-DOS disk) and convert them to .T files for use with ZX81 Emulator.

Type DIR or DIR /p for MS-DOS directory. ESC stops reading.  Now enter the full filename and press Return and the rest should
go without saying.

* SLOW allows you to load ZX81 programs from tape and convert them to .T files for use with ZX81 Emulator.

Press Return when it asks you to type in ZX81 program name. When a program has been loaded succesfully from tape, stop your tape recorder and press Control to save to floppy or harddisk.  To load another file press F4. I've found out that most programsload best if you select recorder type 1 (standard).

Greetings to: MG, Robert van der Veeke, Edwin Blink, Oswald,  Stefan Drissen, Johan Koelman, Ernst, Les Quinn, Graham Goring, Derek Morgan, Dave Whitmore, Andrew Collier and all other...

Happy gaming!