Difference between revisions of "MIT AI lab IO bus interface for GE Datanet 760"
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| − | Device number 750. CONI 100 means ready to accept data. CONO 200 is some kind of reset or enable, and the low three | + | Device number 750. CONI 100 means ready to accept data. CONO 200 is some kind of reset or enable, and the low three bits is the PI channel. DATAO sends a character, which might be 7 or 8 bits. |
The output is some kind of communication protocol to the controller. The bulk of the work here will be to reverse engineer the protocol. | The output is some kind of communication protocol to the controller. The bulk of the work here will be to reverse engineer the protocol. | ||
Revision as of 16:01, 18 December 2023
The MIT AI lab PDP-6 had a GE Datanet 760 controller with four consoles. The controller was attached through two IO bus devices. This article documents the IO bus interface as used by ITS 138.
GTYI
Device number 70 (octal). CONI 10 means data ready. CONO low three bits is the PI channel. DATAI gets a an ASCII character in the right half, and console number in the left half.
GTYO
Device number 750. CONI 100 means ready to accept data. CONO 200 is some kind of reset or enable, and the low three bits is the PI channel. DATAO sends a character, which might be 7 or 8 bits.
The output is some kind of communication protocol to the controller. The bulk of the work here will be to reverse engineer the protocol.
During initialization ITS sends this sequence for each console: 001, "select console", 000, 002, 014, 003, "checksum". Select console is 140 plus the console number in bits 3-4. The checksum is computed over "select console" through 003. The checksum calculation starts over from 0 each time. The checksum computation will be analyzed later.
