observed:

When BASIC stores a program on cassette, it inserts a CTRL/Z after the last line. The AIM 65 Editor will strip off the CTRL/Z when it retrieves the program. Therefore, before storing a BASIC program from the Editor, the user must insert a CTRL/Z following the last line of the program.

H ATN IMPLEMENTATION

The ATN function (see Subject 307) can be programmed in RAM using the AIM 65 Mnemonic Entry (I) and Alter Memory Locations (/) commands, as shown below. The program is written

for the AIM

65

with

4K

bytes of RAM. The ATN function can be relocated elsewhere in memory

by changing

the

starting addresses of the instructions and constants, the conditional branch

addresses, the

vector to the constants start address and the vector to the ATN function starT

address.

 

 

 

 

 

ATN FUNCTION CONSTANTS

ENTERED BY ALTER MEMORY <M>

<M> = 0F80

XX

XX

XX

XX

Constants Starting Address = 0F80

</> = 0F80

0B

76

83

83

8

</>

0F84

BD

D3

79

1E

 

</>

0F88

F4

A6

F5

7B

 

</>

0F8C

83

FC

B0

10

 

</>

0F90

7C

0C

1F

67

 

</>

0F94

CA

7C

DE

53

 

</>

0F98

CB

C1

7D

14

 

</>

OF9C

64

70

4C

7D

 

</>

0FA0

B7

EA

51.

7A

 

</>

0FA4

7D

63

30

88

 

</>

0FA8

7E

7E

92

44

 

</>

0FAC

99

3A

7E

4C

 

</>

0FR0

CC

91

C7

7F

 

</>

0FB4

AA

AA

AA

13

 

</>

0FR8

81

00

00

00

 

</>

0FBC

00

 

 

 

 

ATN FUNCTION INSTRUCTIONS STORED BY MNEMONIC ENTRY (I)

<I>

 

 

 

 

 

 

XXXX *=0FBD

 

 

 

 

Instructions Starting Address = 0F8D

0FBD A5 LDA

AE

 

 

 

 

0FBF 48 PHA

 

 

 

 

 

0FC0 10 BPL

0FC5

 

 

 

0FC2 20 JSR

CCB8

 

 

 

0FC5 AS LDA

A9

 

 

 

 

0FC7 48 PHA

 

 

 

 

 

0FC8 C9 CMP

#81

 

 

 

 

0FCA 90 BCC

0FD3

 

 

 

0FCC A9 LDA

#FB

 

 

 

 

0FCE A0 LDY

#C6

 

 

 

 

0FD0 20 JSR

C84E

 

 

 

0FD3 A9 LDA

#80

\

 

 

Starting Address of Constants = 0F80

0FD5 A0 LDY

#0F

/

 

 

 

0FD7 20 JSR

CD44

 

 

 

0FDA 68 PLA

 

 

 

 

 

0FDB C9 CMP

#81

 

 

 

 

0FDD 90 BCC

0FE6

 

 

 

0FDF A9 LDA

#4E

 

 

 

 

0FE1 A0 LDY

#CE

 

 

 

 

0FE3 20 JSR

C58F

 

 

 

0FE6 68 PLA

 

 

 

 

 

0FE7 10 BPL

0FEC

 

 

 

0FE9 4C JMP

CCB8

 

 

 

0FEC 60 RTS

 

 

 

 

 

0FEC

 

 

 

 

 

 

BASIC INITIALIZATION FOR ATN FUNCTION

BASIC memory must be initialized below the memory allocated to the ATN function. The ATN vector in RAM must also be changed from the address of the FC error message to the starting

Page 255 Page 257
Page 256
Image 256
Apple II ATN Implementation, Entered by Alter Memory M, OF9C, 0FAC, 0FBD A5 LDA 0FBF 48 PHA, CCB8 0FC5 AS LDA, 0FC8 C9 CMP
Page 255 Page 257

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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