Pixel exact emulation of the Commodore 128,Commodore 64, Spectrum 48/128K,VIC 20 and Atari 2600 

Z64K should run on any platform with an updated java runtime environment installed. I will update this site when I get some free time but in the mean time feel free to drop me a message via the contact page with feedback or questions. The changelog only includes changes not shown on this homepage.

Use -Dsun.java2d.d3d=false Java VM option if UI shows glitches.

eg. use javaw -Dsun.java2d.d3d=false -jar Z64K.jar to start Z64Kvia command line.

*tip: ALT-ENTER togglesfullscreen mode

***JAVA 9, 10 and 11 users should use the –Dsun.java2d.uiScale=1.0 option if the screen does not render nicely on your setup.  See https://bugs.openjdk.java.net/browse/JDK-8189416***

LINUX users: You might need to change the permission of Z64K.jar to allow execution. e.g. chmod +x Z64K.jar. 


Latest version 2 of Z64K in development stage. Requires JRE 8 or better. For latest features use this version.*
* last updated 18October2021

Z64K.jar Z64K.jar
Size : 2057.646 Kb
Type : jar
commandline.txt commandline.txt
Size : 2.583 Kb
Type : txt
changelog.doc changelog.doc
Size : 1104.5 Kb
Type : doc
z64k_quick_guide.txt z64k_quick_guide.txt
Size : 6.989 Kb
Type : txt



Version 1 of Z64K.
.
Note: This version is no longer being updated except for bug fixes..

Z64K.jar Z64K.jar
Size : 2158.658 Kb
Type : jar

Keyboard shortcuts

  • ALT+O = Toggle output of VICIIe/VDC to main screen (C128 only)
  • ALT+2 = Toggle 2nd display ON/OFF (C128 only)
  • ALT+ENTER = Toggle Fullscreen mode
  • ALT+INSERT = Paste text from clipboard
  • ALT+DELETE = Copy screen text to clipboard
  • ALT+Q = Toggle capture mouse (C128 & C64)
  • ALT+R = Soft reset
  • CTRL+ALT+R = Hard reset
  • ALT+W = Toggle Warp mode

AdditionalC128 keys

F1=ESC
F2=TAB
F3=ALT
F4=CAPS LOCK
F5= HELP
F6=LINE FEED
F7=40/80 DISPLAY
F8=NO SCROLL

The following keymappings override the values in the keyboard configuration editor for the C128
F9 = F1/F2
F10= F3/F4
F11= F5/F6
F12=F7/F8

Other changes are:-
PC CAPS LOCK = C128 SHIFT LOCK
For emulated NUMPAD Joystick Num Lock needs to be OFF.
C128 NUMPAD keys works with Num Lock ON.


There is an option to enable/disable extra c128 keys via settings==>setup==>Extended Keyboard keys in the latest downloadable version of the emulator. Default is enable extended keyboard keys in C128/CPM modes only.

The C128 Direction keys are mapped to PC cursor keys, and CRSR U/D and CRSR L/R mapped to PC NUMPAD / and * when Extended Keyboard keys enabled.

Version 1- http://www.z64k.com/resources/Z64K.jar

Version 2 (in development) - http://www.z64k.com/resources/version2/Z64K.jar

UNLESS otherwise stated assume updates apply to Version 2 of Z64K only

18 October

  • Disable audio master gain adjustment for systems that don't support it.

12 October

  • Updates to Swiftlink cartridge to support retroterm
  • Included buffer free progress bar in settings for internal userport modem.
  • Improved some rs232 badly formed address error handling.
  • Echo, quiet and verbose toggle button available in settings for userport internal modem
  • Set echo default to false.  Prevents UP9600 driver in Striketerm being locked if modem on when driver selected
  • Detect when client disconnects.
  • Minor improvements to Hayes Modem command mode behavior.
  • Internal modem echo on and quiet off by default.  Echo only in command mode.

10 October

  • Improved timing of userport rs232 receiving of data.  Streaming of audio using retroterm 0.13 plays audio stream at correct speed and no longer causes modem buffer to overflow when playing long streams. 

9 October

  • Increase internal modem buffer size

4 October

  • Minor Improvements to Machine Monitor next command behaviour.
  • Added Machine Monitor next (n) command.  Single steps instruction but treats subroutines as a single instruction.  Note to self: Must find some decent icons for the single stepping icons. :)
  • Fixed debugging with monitor for C128 Z80 cpu memory locations $1800-$3fff
  • REU retains memory after reset

2 October

  • Allow Userport modem to send and receive data at same time

30 September

  • Added 57600 baud rate option for userport rs232 to support Retroterm V0.13

26 September

  • Fixed reset bug that wasn't clearing Z80 HALT state when interrupts were disabled.
  • Improvements with Z80 HALT timing
  • More improvements to ZX spectrum snow effect

19 September

12 September

  • Setting of Z80 registers using machine monitor is now functional
  • Setting of Z80/6502 registers with machine monitoruses current radix

30 August

1 August

  • Default internal modem with echo off, verbose on, and quiet on.
  • Improved internal modem Hayes command set.

31 July

  • Option to disable userport rs232 modem emulation.  Allows connection to tcpser etc.

29 July

  • Fixed broken fast 1581 serial caused by recent changes to support UP9600

28 July

  • Included a default keyboard mapping for German keyboards thanks to Tokra . Disclaimer: not thoroughly tested but is much better than the default English mapping when using a German Keyboard. :)
  • Fixed restore key for VIC20.

27 July

  • VIC 20 uses mike-pal.vpl as default
  • Some minor fixes with timing of VIC interlace signal
  • Userport rs232 modem synchronisation greatly improved.  Data transfers much more reliable with UP9600 and standard userport drivers.
  • Minor adjustment to value read for VIC $9004 register when in NTSC mode depending on cycle

25 July

  • Added UP9600 rs232 modem support.
  • Fixed bug with automatic loading of SDR value into CIA shift register when loaded at same time as final bit of previous SDRshifted out.

23 July

  • Improvements to Userport RS232.  Huge improvement with sending valid data!
  • Fixed ZX spectrum settings title
  • Allow ZX spectrum to be default application on startup 

21 July

  • Fixed bug with command line option -limitcycles that caused it not to trigger with TestBench scripts.

20 July

  • Minor change to latching behaviour to trigger on correct edge as set in ACR. Drive sends pulse from byte ready signalto trigger latching.

18 July

  • Update to VIA port latching.  Fixes VICE bug#582 and Freespin still works!

14 July

  • Fixed bug with VIA latching not clearing when CA1 interrupt is cleared.  Freespin demo doesn't crash anymore. :)
  • Added undocumented drive machine monitor commands motor and track
    motor [on:off] - turn motor on/off , without arguments prints status of drive motor
    track [in:out] - move rw head in/out 1 half track, without arguments prints current track

11 July

10 July

  • Enabled Internal Palette selector available in settings.
  • Updated default VDC palette to c128-vdc-deekay.vpl as suggested by Deekay in the readme of the Colour Spectrum demo.
  • Freespin runs on 1571 drive in addition to 1541
  • C128 support of drive GPU required for Freespin demo
  • Improved sync detection. Freespin display a lot more stable (when it actually runs).
  • Fixed bug with VIA reset code that would lock drive if PB7 output was on.  Freespin no longer locks the drive after reset.

9 July

  • Show correct frames/second in the frame title for all video chips, including simulated drive gpu.
  • Added sound support for Freespin demo.  note: Demo still does not run reliably every time yet in emulation but it is improving.  

8 July

  • Improved Freespin demo support.  Better drive sync detection. Displays graphical effects correctly (when it works)  warning: sometimes crashes the drive where the entire emulator needs to be closed and restarted.  Freespin support is still a work in progress.

    To play the Freespin demo, after the drive code has loaded, select Drive GPU from Machine settings==> Model panel.  When screen turn blacks reattach the same disk image to start the demo.
  • Fix debugging of Z80 LD A,I and  LD A,R

5 July

  • Added option to use disk drive as GPU for Freespin demo.  note: Not reliable and does not play sounds yet.
  • Some improvements to userport rs232 emulation.