The Web Site to Remember National Semiconductor's Series 32000 Family


The Opus board from 1985 is based on the NS32016D-10 CPU with nearly all the peripherals of the family : MMU, FPU and TCU. Main memory is 2 Mbytes of DRAM with partity protection. 1 Mbytes is placed on an add-on board screwed to the main board. The system does not have a boot ROM. Therefore everything is programmed from the host which is obviously a PC. The connector is used for 8-bit ISA slots.

Fig. 1. PC add-on card from Opus.

The photo in Figure 2 shows two boards from Opus in comparison. The upper board is based on the NS32032 CPU. This board uses a large memory expansion board for a total memory size of 4 Mbytes. The lower board is of the same type as in Figure 1 (please note the different series numbers in the upper right corner of the boards). The NS32032 CPU is placed in the upper right corner just below the series number C2301.

The Opus boards were used in CAD systems. For this kind of application they were sold with a large memory array. 144 DRAM chips, each 256-kbit in size, were used for the memory of the NS32032 system. 36 of them are placed on the main board. For the remaining 108 chips an own board was used which equals the size of the main board. Both boards are screwed togehter.

Fig. 2. Two PC add-on cards from Opus.

The photo in Figure 2 is available in higher resolution here .

Unfortunately all the CAD software is lost. Other software is not available too. Even one of the founder of Opus has none according to a remark in a forum entry in the year 2002, see!topic/comp.sys.nsc.32k/VNfyxmgaD-w. In addition up to now no documentation about the hardware could be found. Therefore I plan to build an ISA bus simulator based on an FPGA to see whether the boards are still functional.

The application note AN-587 contains a hint to Opus boards on page 4.

This chapter was last modified on 17 May 2017. Next chapter: PC532