Search found 887 matches

by siggi
Mon Jan 13, 2020 3:51 pm
Forum: Sinclair Misc
Topic: ZX80 and 81 Paint Job Designs for Gran Turismo PS4
Replies: 4
Views: 486

Re: ZX80 and 81 Paint Job Designs for Gran Turismo PS4

That is my small ZX81 in real live:

Image

Please note its 48 K(g) ram (room) expansion on its rear:

:mrgreen:

Siggi

PS: Full details here:
forum.tlienhard.com/phpBB3/viewtopic.php?f=3&t=775
by siggi
Tue Jan 07, 2020 10:33 am
Forum: Emulators
Topic: Is there any Emulator supporting VDrive (vinculum) emulation?
Replies: 2
Views: 572

Re: Is there any Emulator supporting VDrive (vinculum) emulation?

Or maybe a real hardware vdrive connected to a PC? Set the jumper on VDRIVE2 to enable the serial mode (not the SPI mode) and use a converter from 5V TTL level (at VDRIVE2) to RS232 levels at PC. Then use a real COM port (or USB-adapter for a virtual COM port) to talk to VDRIVE2 (using a terminal e...
by siggi
Tue Dec 10, 2019 12:59 pm
Forum: Hardware
Topic: ZX80 no "K" prompt
Replies: 12
Views: 1092

Re: ZX80 no "K" prompt

albertusj wrote:
Tue Dec 10, 2019 10:59 am
C11 was missing! I forgot to put in one tiny 47pF capacitor. I'm such an idiot!
I also won't be happy, if my C5 would be missing ...

forum.tlienhard.com/phpBB3/viewforum.php?f=10

;)

Siggi
by siggi
Mon Dec 09, 2019 12:42 pm
Forum: Development
Topic: New year, new projects?
Replies: 12
Views: 2304

Re: New year, new projects?

A memory chip like EEPROM can replace a GAL, if the GAL performs only simple logic AND/OR/NOT functions. But a GAL can also do more complex things like timing dependent actions (has edge-triggered inputs) or can implement a state-machine (using internal latches)! Then it is not possible to replace t...
by siggi
Mon Oct 28, 2019 8:44 pm
Forum: Software
Topic: Porting PDP11/VAX programs to the ZX81
Replies: 2
Views: 1582

Re: Porting PDP11/VAX programs to the ZX81

Hi Stefano thanks for that programs. Seems that the Zeddy is PDP11-compatible :mrgreen: Back in the eighties I also wrote a Hanoi program, running on my Sharp PC 1211 (so no graphics, BASIC, no recursion). But the graphic version on ZX81 looks much better. Here are some pics: IMG_4988_1024x768.JPG I...
by siggi
Fri Jul 05, 2019 12:00 pm
Forum: Emulators
Topic: XavSnap Anomalies
Replies: 5
Views: 1318

Re: XavSnap Anomalies

When I ported Chopper Drop 3000 to be compiled by MCODER2, the basic program size got bigger than 16K (the generated machine code is inserted into REM in line 1). The the DFILE then moved above 32K (afaik it must be completely moved across the 32K boundary to avoid a crash). BUT THEN THE M1-LOGIC (w...
by siggi
Tue May 28, 2019 9:38 am
Forum: Sinclair Misc
Topic: Did the original ZX80 "new" ROM really contain.....
Replies: 3
Views: 1579

Re: Did the original ZX80 "new" ROM really contain.....

As fa as I remember I read somewhere (in this forum???) something about the developer of this rom: he told, that the printer code was added in the final development phase just before releasing the ZX80. So maybe some prototype roms contains this code, but not the released roms.

Siggi
by siggi
Tue May 14, 2019 10:20 am
Forum: ZX BASIC
Topic: ZX81X2.ROM - and the big bang
Replies: 36
Views: 11089

Re: ZX81X2.ROM - and the big bang: compatibility problem?

Hi there seems to be a problem: this file contains in variable A$ the source code for an assembler file (for ASDIS). The basic program contains only REM. If the program is loaded e. g. by EO and ZX81.rom and I press RETURN, the listing is written to screen and the Zeddy is alive. If the program is l...
by siggi
Mon Apr 15, 2019 9:15 am
Forum: ZX BASIC
Topic: MC INKEY$ replacement
Replies: 2
Views: 1189

Re: MC INKEY$ replacement

Hi Greg this is not a real "inkey" function like in BASIC. The BASIC inkey$ function reads the keyboard "on the fly" and does not wait for a key to be pressed. But this mc stays inside a loop (and does not return) if no key is pressed: @Again Call Keyboard ;Call ROM scan keybd. INC L ;Check for no k...
by siggi
Fri Apr 12, 2019 10:28 am
Forum: Development
Topic: How to Build a keystick port internally to zx81
Replies: 5
Views: 1043

Re: How to Build a keystick port internally to zx81

Connecting a joystick directly to the keyboard lines will overload the Z80 addressbus (driving the keyboard lines), because the capacitive load of the long cable to the external joystick is too high. At least some additional components (transistors or driver ICs) are necessary to drive this long cab...