150 (NORD-1 card)

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150 Register, is a card that is used as the instruction register in the NORD-1 CPU. It holds the current instruction during execution.

Component side.
Solder side.

Introduction

The card is made in the standard NORD-1 card format.

CPU model Crate position
29 C09
35 C09

The logic diagram is documented in drawing 2A50.[1]

The content of the IR is set by the MJ-bus and strobed by the IS1-0 signal on pin 29 and 30. The IS2-0 strobe forces the IR to 161402 (IOT SKA #2) or 161422 (IOT SKA #22) depending on the state of LEN-1, this is a load sequence initiated from the operators panel.

IS2-0 strobe comes from the 122 Assembler card, where the IS1-0 signal comes from isn't known yet.

Switches and indicators

There are no switches or indicators on this board.

BOM

This list contains the logic circuits used, passive components are not listed.

  • 4 x 7400
  • 4 x 7440
  • 8 x 7474

Reference

  1. HARDWARE MANUAL NORD 1