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TOPIC -- Apple II -- WOZPAK Sweet-16 article by Dick Sedgewick

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SWEET 16 - INTRODUCTION

by Dick Sedgewick

Sweet 16 is probably the least used and least understood seed in the Apple ][.

In exactly the same sense that Integer and Applesoft Basics are languages, SWEET 16 is a language. Compared to the Basics, however, it would be classed as low level with a strong likeness to conventional 6502 Assembly language.

To use SWEET 16, you must learn the language - and to quote "WOZ", "The opcode list is short and uncomplicated". "WOZ" (Steve Wozniak), of course is Mr. Apple, and the creator of SWEET 16.

SWEET 16 is ROM based in every Apple ][ from $F689 to $F7FC. It has it's own set of opcodes and instruction sets, and uses the SAVE and RESTORE routines from the Apple Monitor to preserve the 6502 registers when in use, allowing SWEET 16 to be used as a subroutine.

It uses the first 32 locations on zero page to set up its 16 double byte registers, and is therefore not compatible with Applesoft Basic without some additional efforts.

The original article, "SWEET 16: The 6502 Dream Machine", first appeared in Byte Magazine, November 1977 and later in the original "WOZ PAK". The article is included here and again as test material to help understand the use and implementation of SWEET 16.

Examples of the use of SWEET 16 are found in the Programmer's Aid #1, in the Renumber, Append, and Relocate programs. The Programmer's Aid Operating Manual contains complete source assembly listings, indexed on page 65.

The demonstration program is written to be introductory and simple, consisting of three parts:

1.Integer Basic Program

2.Machine Language Subroutine

3.SWEET 16 Subroutine

The task of the program will be to move data. Parameters of the move will be entered in the Integer Basic Program.

The "CALL 768" ($300) at line 120, enters a 6502 machine language subroutine having the single purpose of entering SWEET 16 and subsequently returning to BASIC (addresses $300,

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Apple II manual Sweet 16 Introduction
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II specifications

The Apple II, launched in April 1977, was one of the first highly successful mass-produced microcomputer products. It marked a significant leap in personal computing, setting standards for future developments in the industry. Created by Steve Wozniak and Steve Jobs, the Apple II differentiated itself with its user-friendly design, appealing aesthetics, and robust capabilities.

One of the standout features of the Apple II was its open architecture, which allowed users to expand and enhance the computer's functionality. This design enabled hundreds of third-party hardware and software developers to contribute to its ecosystem, resulting in an array of peripherals, including printers, modems, and storage devices. The Apple II utilized a MOS Technology 6502 microprocessor running at a clock speed of 1 MHz. Initially equipped with 4 KB of RAM, the machine could be expanded to 48 KB, accommodating more complex applications and programs.

The Apple II was also notable for its colorful graphics. It was one of the first computers to support color display, offering a 6-color palette with a resolution of 280x192 pixels in 16 colors when using its Color Graphics Card. This feature significantly enhanced the visual appeal of games and educational software developed for the platform, making computing more accessible and entertaining for various audiences.

Apple's commitment to user experience was evident in the design of the machine. It featured an integrated keyboard and a plastic case, which was both durable and visually appealing. The self-contained design included drive bays for floppy disk drives, allowing for quicker data access than traditional tape drives. It also supported audio output, enabling sound effects and music, a novelty at the time.

The introduction of the Apple DOS operating system further underscored the machine's capabilities. DOS streamlined file management and made it easier for users to navigate and manage their data. The combination of hardware and software positioned the Apple II as an educational tool and a gaming platform, fostering a vibrant software ecosystem.

The Apple II family continued to evolve, with variations like the Apple II+, IIe, and IIgs being introduced over the years. These iterations brought enhancements in memory, processing power, and graphics capabilities. The legacy of the Apple II endures, not only as a foundational product in personal computing but also as a symbol of innovation that paved the way for future advancements in technology. Its impact is still felt today, as it inspired countless developers and shaped the trajectory of the computer industry.
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