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


NS32016/NS32032 based systems

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.

NS32532 based system

Until June 2017 I was believing that the german company Mikron has built an NS32532 based add-on board for the PC. Now I learned from John C. that the board shown in an advertisement from Mikron is an Opus board. Mikron is "only" a systemintegrator.

In 1988 Mikron offered the board with 4 Mbytes of DRAM together with software for ~10,000 which is very high from today's perspective. For this money you got at the end of the 1980's a new VW Golf. A complete system with a Compaq Deskpro 386 PC as a host, a graphic card and a 19" Sony color monitor was offered for ~40,000 . This was the price of a new Porsche!

Fig. 3. The NS32532 based PC add-on board for the 16-bit ISA bus.

The board runs a variety of System V. The two Xilinx FPGAs (XC2018-70, 100 logic cells) are loaded at MSDOS startup. Unix hard disk access was through a helper-program which ran under MSDOS.

Fig. 4. A partially populated daughter card for memory expansion screwed to the CPU board.

The daughter card in Figure 4 has DRAMs on both sides of the PCB. Fully populated it has a capacity of 16 MBytes. Together with the 4 MBytes of the CPU board a system may have 20 MBytes in total. The memory is parity protected.

Fig. 5. A detailed view of the CPU and FPU.

Fig. 6. The board was designed and made in the USA. Please note that the manufacturer of the DRAMs was Motorola.

This chapter was last modified on 11 June 2017. Next chapter: PC532