Atari 800D Developer System  


 U4/U5 ROM Images

 Atari LNBUG 6.0 6500 Dev System






System Overview

The Atari 800D appears to be a modified Atari 800 computer system with a different CPU Board that passes through the Bus signals over to a board that occupies the previously unused Left section of the Atari 800 case.

The left side of the Atari 800 case is redesigned to accommodate this new Left Side panel.   A Ribbon cable from the CPU feeds over to the Left Side Interface board.   The System BUS signals pass through the Left Side Interface board and go out through a 40 pin connector.  This appears to be the first implementation of the Atari "PBI" (Parallel Bus Interface) on any Atari computer system.

On the Left Side Interface Board there are also 2 DB9 connectors which are tied in with a pair of MC6850 Asynchronous communication adapter (ACIA) chips.  There is also an SMC 8116 Baud Rate Generator.

2 ROM chips located at IC locations U4 and U5 supply the device drivers for the board.

Essentially what Atari did was provide the Atari 800 with built in Serial communication ports and an External Expansion port.


CPU Board:

Atari 800D CPU Board (Front)

Atari 800D CPU Board (Back)


Left Interface Technical Information: