Making an Atari 2600 Cartridge

How I built my Custom Atari 2600 Cartridge

Aquí en Español.


How it was done

Here I show how I built my own Atari 2600 cartridge. This is a little bit technical page (although not much).


This is a picture of the cartridge. You can notice the ROM, the dipswitch, a 4.7 K resistors array and a 4011, used as an inverter. All in a discarted Atari 2600 cartridge. Made in Chile.

Here you can see an enlarged image (58 K JPG).




First Step: Getting the ROM

Well, at first, I had an old atari 2600 Clon machine, which didn't work, but I suspected the ROM was in good work condition, because it displayed the image, but it wasn't possible to play on it.



Atari 2600 Clon: It says 208 games, but they're actually 160.



I took the ROM out, which (fortunatelly) wasn't soldered, but in a base.

It looked as follows:

Notice there are two ROMs, one hooked up on the other. A 4M (512K x 8) memory including 128 4K games, and above it a 512K (64K x 8) memory with 32 2K games. This is something like a 27C512 above a 27C4001, I suggest you to have at hand those EPROMS data sheets for a better understanding of all this stuff. The pin 22 of the lower ROM (OE), that matches the pin 20 of the upper ROM, was manually operated with an external switch, via an inverter. It seems that when, given the same signal, one ROM was active, the other wasn't.

The upper ROM's pin 23 (A11 ?), which is up, is connected to the lower ROM's pin 2 (A16 ?). An interesting way of addressing both memories.

The Atari ROM memories are addressed the same as the commercially available memories, with the exception that the CE pin (Chip Enable) is inverted. For this purpose I used a 4011.

To continue, the Atari 2600 connector pins: (From somewhere in Internet).

The Atari 2600 Cartridge:

________________Top Row__________________Bottom Row__________

Slot

2716

CPU

2716

CPU

1

13

D3

1

A7

2

14

D4

2

A6

3

15

D5

3

A5

4

16

D6

4

A4

5

17

D7

5

A3

6

*

A12

6

A2

7

19

A10

7

A1

8

NC

A11

8

A0

9

22

A9

9

D0

10

23

A8

10

D1

11

24

+5V

11

D2

12

12

Shield Ground

NC

Ground

Note: numbers indicate left to right numbering. * to inverter and back to 18 for chip select

Isn't it enough clear ? Here is much clearer.

This Atari connector information refers to a 2716 EPROM, for a 2K game.

We can conclude we had a 19 direction pins ROM (A0 - A18), from which 12 (A0 - A11, data) are used by the Atari, and there are 7 left to select games (A12 - A18). I made this selection with a simple 8 dipswitch. In this case, the Atari pin 6 top row, A12 (don't mistake this A12 with the ROM's one), attacks directly the ROM's pin OE (Output Enable), through an inverter. The ROM's outputs match with the Atari connector (D0 - D7).

As a result, I drew the following diagram:



Sorry for the diagram, but I've got no further resources. Here you can see the enlargement. Here there is a more detailed ZIP. (484 K).

The diagram says R=10 K. Actually, R=4.7 K. In the diagram, I used the JAMMA standards for the Atari connector.







Second Step: Where to insert the Chip

To continue, I disassembled an old Atari 2600 cartridge in order to insert the ROM. I cut the tiny printed circuit board in a way that only the connector was left, and I screw a printed circuit in to it in order to contain the ROM, the inverter and the dipswitch. (See picture).


It worked perfectly. 160 games for my old Atari 2600 console. They are rather fewer, because some of them are repeated.




It's interesting to notice that dipswitch 1, when is ON, activates a memory and, apparently, the other memory is left with its outputs in third state, and viceversa. The 2600 clon machine came with its "expanded" ROM. Usually, these machines came with a single 128 games ROM. Here goes a list containing all the games (160), and its address in the dipswitch: ("-"= don't care).

Cartridge 160 in 1 - Atari 2600

**********************************************************

Switches

12345678

Game

94

1011101

*No Game*

46

101101

?? (Labyrinths, Enem. appear and disappear)

107

1101010

Galactic

129

1--00000

3D Tic-Tac-Toe

13

1100

Air Raiders

134

1--00101

Air-Sea Battle

34

100001

Alien

21

10100

Alien's Return

19

10010

Amidar

47

101110

Assault

11

1010

Assault (Clon)

12

1011

Atlantis

127

1111110

Atlantis

73

1001000

Bank Heist

125

1111100

Barnstorming

147

1--10010

Basic Math

148

1--10011

Basketball

76

1001011

Beany Booper

39

100110

Bermuda

105

1101000

Berzerk

90

1011001

Blackjack

159

1--11110

Blackjack

45

101100

Bobby Is Going Home

16

1111

Boom Bang

136

1--00111

Bowling

132

1--00011

Boxing

22

10101

Brick Kick

77

1001100

Bridge

5

100

Canyon Bomber

43

101010

Carnival

23

10110

Challenge

157

1--11100

Checkers

52

110011

China Syndrome

126

1111101

Chopper Commando

72

1000111

Circus

101

1100100

Commando Raid

1

0

Condor Attack

51

110010

Cosmic Ark

3

10

Cosmic Creeps

137

1--01000

Cosmic Swarm

57

111000

Crackpots

26

11001

Criminal Pursuit

55

110110

Crossforce

116

1110011

Cruise Missile

42

101001

Dark Cavern

18

10001

Deadly Duck

110

1101101

Defender

113

1110000

Demon Attack

15

1110

Dishaster

114

1110001

Dodge 'Em

29

11100

Donkey Kong (Clon)

84

1010011

Dragonfire

97

1100000

Dragster

17

10000

Enduro

92

1011011

Fantastic Voyage

36

100011

Fast Eddie

78

1001101

Fire Fighter

143

1--01110

Fishing Derby

146

1--10001

Flag Capture

62

111101

Flash Gordon

141

1--01100

Football

151

1--10110

Freeway

142

1--01101

Freeway (Rabbits)

124

1111011

Frogger

37

100100

Frogs And Flyes

68

1000011

Frostbite

58

111001

Gas Hog

96

1011111

Ghoper

139

1--01010

Golf

30

11101

Grand Prix

70

1000101

Hangman

156

1--11011

Homerun

155

1--11010

Human Cannonball

80

1001111

Ice Hockey

60

111011

International Soccer

100

1100011

Jawbreak

24

10111

Karate

109

1101100

Keystone Capers

40

100111

King Kong

131

1--00010

Laser Blast

140

1--01011

Laser Blast (Bird)

74

1001001

Laser Gates

120

1110111

Lock'n Chase

102

1100101

M*A*S*H

67

1000010

M.A.D.

53

110100

Master Builder

119

1110110

Math Gran Prix

115

1110010

Mazecraze

56

110111

Megaforce

83

1010010

Megamania

8

111

Meteor Defense

160

1--11111

Miniature Golf

28

11011

Missile Command

99

1100010

Mission 3000 AD

7

110

Mouse Highway

44

101011

Mr. Postman

117

1110100

Name This Game

65

1000000

Nexar

54

110101

Nuts

75

1001010

Oink!

130

1--00001

Otello

149

1--10100

Outlaw

123

1111010

Pac-Kong

122

1111001

Pac-Man

106

1101001

Pele's Soccer

86

1010101

Pitfall!

32

11111

Planet Patrol

63

111110

Plaque Attack

61

111100

Pooyan

59

111010

Q*Bert

95

1011110

Racquetball

108

1101011

Raft Rider

69

1000100

Real Sports Volleyball

112

1101111

River Raid

27

11010

Save Our Ship

50

110001

Sea Hawk

35

100010

Sea Monster

79

1001110

Seaquest

145

1--10000

Skiing

158

1--11101

Sky Diver

152

1--10111

Sky Diver (Boxes)

4

11

Sky Jinks

153

1--11000

Slot Machine

138

1--01001

Slot Racers

14

1101

Snail Against Squirrel

49

110000

Space Cavern

111

1101110

Space Invaders

6

101

Space Raid

10

1001

Space Robot

103

1100110

Spacemaster X-7

82

1010001

Spider Fighter

25

11000

Spiderman

93

1011100

Squeeze Box

133

1--00100

Stampede

154

1--11001

Stampede

128

1111111

Star Wars: The Empire Strikes Back

31

11110

Sub Scan

87

1010110

Super Challenge Baseball

85

1010100

Superman

144

1--01111

Surround

64

111111

Tac-Scan

150

1--10101

Tank

38

100101

Task Force

135

1--00110

Tennis

66

1000001

The Earth Dies Screaming

71

1000110

Thunderground

9

1000

Tom Boy

33

100000

Towering Inferno

20

10011

Traffic

81

1010000

Trick Shot

2

1

Tuby Bird

88

1010111

Turmoil

118

1110101

Ufo Patrol

48

101111

Venture

91

1011010

Video Chess

89

1011000

Video Pinball

121

1111000

Word Zapper

98

1100001

Worm War

41

101000

X-Tack

104

1100111

Yars' Revenge


Only classics! That's the way they played almost 20 years ago. There's one game I can't identify, I must admit. If someone surmises which game it is, please let me know.

As an extension to this little project, BIN files could be downloaded from Internet, burn them into a 4M EPROM (27C4001 or similar) and plug it into this cartridge. It should work. I've tried to take out another ROM from another 2600 clon and it worked well alike.

Nowadays I'm thinking of building an EPROM burner and try it.


Some related Links:

These are some of the sites where I got the necessary information for this project:

http://members.cox.net/rcolbert/multi.htm

http://www.netway.com/~hozervideo/atari/makecart.html

http://www.tripoint.org/kevtris/

http://users.erols.com/tiltonj/index.html


Comments, critics, congratulations, disqualifications or whatever message to gamemasterquilpue in:

gamemasterquilpue@hotmail.com

Another interesting page on ATARI 2600: http://es.geocities.com/gamemasterquilpue/indy500hack.htm

You can visit my main page too http://www.ericzone.50megs.com .And you can also see a list of my all kinds and all ages videogames collection in http://es.geocities.com/gamemasterquilpue

Contador

Quilpué, V Región, Chile, May of 2001.

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