| Beginners' BASIC: More on INKEYS |
Tutorial on using INKEY$ in 8K ZX81 BASIC programs, covering two techniques: stopping execution if any key is pressed (using PAUSE and IF INKEY$<>” pattern) and stopping execution until a key is pressed. Explains the null-string comparison and demonstrates keyboard-controlled reset and stopping logic. |
Timex/Sinclair 1000 |
| Dear Editor |
Letters covering: FAST/SLOW mode switching in machine code monitors (Clark Calkins, answered by KO); expanding ZX81 on-board RAM to 2K using Fujitsu MB8416 static RAM (William Jordan); disabling SPACE-key interruption and CONT screen clearing (C. Alfred Spencer, answered by KO); explanation of Syntactic Sum meaning (Julian Goldman); Syntactic Sum FAST mode requirement and SAVE anomaly |
MicroAce, Sinclair ZX80, Sinclair ZX81, Timex/Sinclair 1000 |
| Flying Bird |
Short 8K BASIC routine demonstrating animated graphics: displays a flying bird (or bat if PAUSE statements removed) by alternating two character patterns. Speed controlled by PAUSE statement values. |
Sinclair ZX81, Timex/Sinclair 1000, Type-in program |
| Grandson of Big Characters |
Update of John Filley’s ‘Son of Big Characters’ program for 8K ROM and 1K RAM. Displays 2 lines of 16 large characters. Uses Boolean-free logic for 8K ROM compatibility (AND/OR no longer operate as bit manipulators in 8K ROM). Supports inverse video with a single line change. |
Timex/Sinclair 1000, Type-in program |
| Hardware Project: Simple 4K-8K ROM Switch |
Step-by-step guide for building a piggyback ROM switch to run both 4K integer BASIC and 8K ROMs in the ZX80 without swapping chips. Uses a single-pole switch mounted inside the ZX80 case, with both ROMs soldered together except at pin 24 (Vcc), which is switched to activate one ROM at a time. |
Sinclair ZX80 |
| Household Finances — 8K/16K |
Personal finance program for tracking household income and expenses in up to 10 user-defined categories (8 expense, 2 income). Includes monthly and yearly summaries, a self-saving option, and protection against accidental erasure. Requires 8K ROM and 16K RAM, leaving ~12.6K for data. |
Timex/Sinclair 1000, Type-in program |
| Improved Data Input |
Subroutine for improved data input using INKEYS, providing a blinking block cursor at the current screen position, RUBOUT support, and return of entered data in variable C$. Replaces the standard INPUT statement to allow data entry at arbitrary screen positions. |
Timex/Sinclair 1000, Type-in program |
| Keyboard Scanning from Machine Code |
Explains how to scan the ZX80/81 keyboard from machine code in SLOW mode using the LAST K system variable (16421-16422). Covers key-value demonstration, FAST/SLOW mode selection from machine code using ROM addresses, and presents a complete machine code keyboard scanning routine that mirrors Sinclair’s own BASIC keyboard feel. |
Sinclair ZX80, Timex/Sinclair 1000 |
| MC Programming: PUSHing and POPping (Part 7) |
Seventh installment of the machine code series, covering the Z80 PUSH and POKE stack instructions for preserving register pairs during machine code subroutines. Explains how to avoid crashing the ZX80/81 by PUSHing registers before use and POPping before returning to BASIC. Includes three rules and FAST/SLOW mode notes. |
Sinclair ZX80, Timex/Sinclair 1000 |
| News, New Products |
News section covering: Timex plans for TS1000 retail in major department stores with 14 software titles; Mindware introducing the MW100 16-column dot-matrix printer for 8K ZX/TS1000; National Electronics III closes; various new products including Data-assette tape controller, EconoTech 16K RAM, VOTEM analog interface, and LJH keyboard enclosures. |
Timex/Sinclair 1000 |
| Numbers Held Inexactly on the ZX81 (Part 5) |
Fifth and final part of the series, covering FOR-NEXT loop counter behavior with non-integral step values. Explains why floating-point imprecision requires slightly overstating loop limits and rounding with INT(N+.5). Also notes a subtraction quirk in the ZX81’s ROM and its source. |
Timex/Sinclair 1000 |
| Program Improvements: Sort Routine |
Shortened version of Leo Morgan’s string sort routine from Oct. 1981, reducing it by two lines by using an inverted space character (higher code than any standard character) to eliminate boundary-checking lines. |
Timex/Sinclair 1000, Type-in program |
| Tic Tac Toe — 4K/2K |
Two-player Tic Tac Toe game for the ZX80 in 4K ROM with at least 2K RAM. Player vs. computer; computer uses a mix of strategic and random moves. Checks for legal moves, detects wins, and allows replaying. Includes complete BASIC listing. |
Sinclair ZX80, Type-in program |
| Users' Groups |
Listing of recently heard-from ZX80/81 user groups in Central Virginia, Pittsburgh PA, North Suncoast FL, Atlanta GA, Milwaukee WI, Chattanooga TN, and San Diego CA. Includes Gladstone Electronics contact for the Toronto area. |
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