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.

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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.

The chip reference designators was not visible on the board, so we used location references instead.Reference "G89" means that the chip is located at row G, between column 8 and 9.

Dumps of the chips, made with a EPROM programmer

• Left chip: File:Microcode 37932A G89.bin.bz2
• right chip: File:Microcode 37933A G67.bin.bz2

This is version 2 of the microcode.

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