2461

F0B2 A9 06

 

 

LDA

#PRTIME/256 ;START T2 FOR 1.7 MSEC

2462

F0B4 8D 09 A8

 

 

STA

T2H

 

2463

F0B7 20 E3 F0

 

 

JSR

IPSU

;SET NEXT PATTERN WHILE WAITING

2464

F0BA 20 1B EC

 

 

JSR

DE2

;WAIT TILL TIME OUT

2465

F0BD A9 00

 

 

LDA

#0

;THERMAL ELEM OFF

2466

F0BF 8D 01 A8

 

 

STA

DRAH

 

2467

F0C2 AD 00 A8

 

 

LDA

DRB

;BUT DONT CHANGE TAPE CONTROLS

2468

F0C5 29 FC

 

 

AND

#$FC

 

2469

F0C7 8D 00 A8

 

 

STA

DRB

 

2470

F0CA 60

 

 

RTS

 

 

2471

F0CB

 

 

 

 

 

2472

F0CB

; SUBROUTINE PINT -- INIT VARS FOR PRINTER

2473

F0CB A9 FF

PINT

 

LDA

#$FF

 

2474

F0CD 8D 74 A4

 

 

STA

IDIR

;DIRECTION <= -

2475

F0D0 A9 05

 

 

LDA

#5

 

2476

F0D2 8D 75 A4

 

 

STA

ICOL

;COLUMN <= LEFTMOST +1

2477

F0D5 A9 01

 

 

LDA

#1

 

2478

F0D7 8D 76 A4

 

 

STA

IOFFST

;OFFSET <= LEFT CHARACTER

2479

F0DA 8D 7C A4

 

 

STA

IMASK

 

2480

F0DD A9 00

 

 

LDA

#0

 

2481

F0DF 8D 77 A4

 

 

STA IDOT

;DOT COUNTER <= 0

2482

F0E2 60

 

 

RTS

 

 

2483

F0E3

 

 

 

 

 

2484

F0E3

;THE VARIABLES FOR THE PRINTER ARE AS FOLLOWS:

2485

F0E3

;

 

 

 

 

2486

F0E3

;IDIR

 

DIRECT HEAD IS CURRENTLY MOVING (0=+, $FF=-)

2487

F0E3

;ICOL

 

CLMN TO BE PRNTED NEXT (LEFTMOST=0,RIGHTMOST=4)

2488

F0E3

;IOFFST OFFSET N PRINT BUFF (0=LEFT CHR, 1=RIGHT CHR)

2489

F0E3

;IDOT

 

COUNT OF NUMBER OF DOTS PRINTED THUS FAR

2490

F0E3

;IOUTL

SOLENOID PATTERN (8 CHRS ON RIGHT)

2491

F0E3

;IOUTU

SOLENOID PATTERN (2 CHRS ON LEFT)

2492

F0E3

;IBITL

1 BIT MSK USED IN SETTING NEXT SOLENOID VALUE

2493

F0E3

;IBITU

UPPER PART OF MASK

2494

F0E3

;IBUFM

START OF PRINT BUFFER (LEFTMOST CHR FIRST)

2495

F0E3

;IMASK

MASK FOR CURRENT ROW BEING PRINTED

2496

F0E3

;JUMP

 

ADDRESS OF TABLE FOR CURRENT COLUMN

2497

F0E3

;

 

 

 

 

2498

F0E3

; THE DOT PATTERNS FOR THE CHRS ARE STORED SO THAT...

2499

F0E3

;EACH BYTE

CONTAINS THE DOTS FOR ONE COLUMN OF ONE...

2500

F0E3

;CHR. SINCE EACH COLUMN CONTAINS SEVEN DOTS ,

2501

F0E3

;THIS MEANS THAT ONE BIT PER BYTE IS UNUSED.

2502

F0E3

;

THE PATTERNS ARE ORGANIZED INTO 5 TABLES OF 64...

2503

F0E3

;BYTES WHERE EACH TABLE CONTAINS ALL THE DOT...

2504

F0E3

;PATTERNS FOR A PARTICULAR COLUMN. THE BYTES IN EACH...

2505

F0E3

;TABLE

ARE

ORDERED ACCORDING TO THE CHR CODE OF...

2506

F0E3

;THE CHR BEING REFERENCED. THE CHR CODE CAN...

2507

F0E3

;THUS BE USED TO DIRECTLY INDEX INTO THE TABLE.

2508

F0E3

 

 

 

 

 

2509

F0E3

;SUBROUTINE IPSU -- SET UP OUTPUT PATTERN FOR PRINTER

2510

F0E3

; THIS ROUTINE IS CALLED IN ORDER TO

2511

F0E3

;SET UP THE NEXT GROUP OF SOLENOIDS TO

2512

F0E3

;BE OUTPUT

TO THE PRINTER.

2513

F0E3

; ON ENTRY THE CONTENTS OF ALL REGISTERS

2514

F0E3

;ARE ARBITRARY

 

2515

F0E3

; ON EXIT THE CONTENTS OF A,X,Y ARE UNDEFINED

2516

F0E3 A2 00

IPSU

 

LDX

#0

;X POINTS TO VAR BLOCK FOR PRNTR

2517

F0E5 20 21 F1

 

 

JSR INCP

;ADVANCE PTRS TO NXT DOT POSITION

2518

F0E8

;X NOW CONTAINS INDEX INTO PRINT BUFFER

2519

F0E8 BD 60 A4

IPS1

 

LDA

IBUFM,X

;LOAD NEXT CHAR FROM BUFFER

2520

F0EB 29 3F

 

 

AND

#$3F

 

2521

F0ED A8

 

 

TAY

 

 

2522

F0EE A9 7D

 

 

LDA #JUMP

;A<= DOT PATTERN FOR CHAR & COL

 

 

 

 

 

 

 

Page 179 Page 181
Page 180
Image 180
Apple II manual LDA #PRTIME/256 Start T2 for 1.7 Msec
Page 179 Page 181

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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