Perceptions
In this issue I will discuss the ZX80/81’s display system. The ZX80/81 video display is created almost entirely by software. All sync (vertical and horizontal) is generated by 10 instructions in the display routine.
Sinclair ZX80
Kitchen Sync
The first thing we did when we finished building our ZX81 kits was to play with them— poking through the manual, pressing new keys to see what they did, writing little test programs to see what could be done. It did not take us long to decide that the ZX81 had some features that made
Plotting with 4K Basic
If you have only 1K of RAM, this program provides you with a field of 10 lines by 7 columns for plotting. Pixel graphics provide 280 plotting positions: the field is 20 pixels high by 14 pixels wide.
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Try This
Get a small AM radio and tune it for best response. Then press RUN and NEWLINE. Note the sound as you press NEWLINE. The display may be ignored.
Safe Machine Code Routines
More and more programs are appearing in SYNC, under the rubric of “machine language.” There was a time, not too long ago, when personal computer users were notoriously shy about venturing into these jungles. Nowadays, though, even someone who is not quite comfortable in Basic can manage to key in and run programs in Z80
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How to Invent a Game, Part 2
Finishing the programming for the game.
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LSCROLL – For Spectacular Screen Displays
How would you like to be able to create a “Times Square” display which moves from right to left without upsetting other items on your ZX81 (or 8K ROM ZX80) screen? Would you like to display graphs or functions such as a sine wave on your screen when they need more than 32 columns of
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The Hidden Chessmen
The Hidden Chessmen is a search and find game like Hurkle. A knight, a bishop, and a rook are hidden on a chessboard by the computer. You begin the play by guessing a square on the chessboard. The computer tells you if you have found a chess piece and/or what pieces are attacking the square.
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“You Are in a Maze…”
“…of twisty little passages, all alike.” This message, in Adventure of Zork, tells you that you have embarked on one of the most challenging phases of the game: mapping the maze and finding your way out. Even without the rest of the dungeon, a maze can make an exciting puzzle in itself —especially if there
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Hampson’s Plane
Program translates the three dimensional Rubik’s Cube to the two dimensional TV screen via the ZX80.
Two Challenges of Taxman
The computer will lay out the integers from 1 to a maximum which you have entered. You pick one of these numbers; Taxman gets all the remaining factors of that number. If there are no remaining factors of the number chosen, you cannot have it. When there are no remaining factors of any unchosen number,
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