Atari 7800 cart connector specifications 1 R/W 32 CLK2 2 Halt 31 IRQ ---------------------------- 3 D3 30 GND 4 D4 29 D2 5 D5 28 D1 6 D6 27 D0 7 D7 26 A0 8 A12 25 A1 9 A10 24 A2 10 A11 23 A3 11 A9 22 A4 12 A8 21 A5 13 +5V 20 A6 14 GND 19 A7 ----------------------------- 15 A13 18 EAudio 16 A14 17 A15 Pins 3-14 and 19-30 are identical to the Atari 2600 and allow the 7800 to utilize existing 2600 cartridges. The remaining pins are 7800 specific pins. R/W - Read/Write signal from the processor, 0 = Write/1 = Read Halt - Input to the processor. This pin halts the processor and tri-states the address and data busses. D0..D7 - Data Bus A0..A15 - Address Bus +5V - +5VDC power to the cartridge GND - Signal ground CLK2 - Phase 2 clock from the processor IRQ - interrupt request to the processor EAudio - extern audio input to the system. Allows the cart to contain extended audio hardware.