3090

3090 is the first ND-110 CPU board (referred to as the "old" CPU card). It contains the CPU, bus arbitration logic, memory control, cache memory and other subsystems, including the Real time clock and the I/O for the serial console.

This article is a stub. You can improve NDWiki by expanding it.

Introduction

This is the "old" ND-110 CPU card.

Switches and indicators

The following switches and indicators are on the card

Location 29J - potentiometer
Location 28J - ALD edge switch
Location 26J - baud rate edge switch
Location 21J - self test lamp (green)
Location 19J - running lamp (red)
Location 15J - cache on lamp (red)
Location 13J - cache on/off switch

Connectors

The A and B connectors are used for I/O, the C connector is used for the ND-100 Bus.

See also

3095 new ND-110 CPU board

Microcode

The microcode for the CPU is held in two EPROMs, 27256.

Location: the board has letters for rows (A, B, C, ...) on the left edge, and numbers (1, 2, 3, ...) at the top edge. Location of any given component on the board is given as a single letter and number (for small components) or as a series of letters and numbers (for larger components, covering more than one row and / or column).

Dumps of the chips, made with a EPROM programmer

• Left chip: File:Microcode 37932A G89.bin.bz2 Location on board: G-8-9
• right chip: File:Microcode 37933A G67.bin.bz2 Location on board: G-6-7

This is version 2 of the microcode. (From an early CPU card, right after prototyping. Used for training the test team in production in the basement at Skullerud)

References

• Norsk Data Document ND–06.026.01 ND-110 Functional Description
• Norsk Data Document ND–30.008.3 EN ND-100 Hardware Maintenance , page 232