Standard 32 Bus

[STD 32 Bus Description] [STD 32 Bus Standards Info] [STD 32 Bus Interface IC's]
[STD32 Board Manufacturers]

STD 32 Bus Description

STD32 which defines a bus with a 32 bit data bus running at 32MBps, was an up-grade of STD Bus; a Scalable back plane bus spec for 8/16 bits. The STD bus and STD32 bus may not be interchanged, and are incompatible. STD bus was developed in 1978, and STD32 in 1989. STD 32 is also a superset of the STD-80 architecture. The STD 32 bus pins reside on 0.0625" centers, which are between the pin spacing of the STD-80 bus. STD 32 cards retain the same form factor and may be inserted into STD-80 connectors. The new 'E' pins for STD 32 reside between the STD-80 'P' pins. This bus uses card edge fingers, etched onto the PWB as traces. STD 32 bus defines the electrical and mechanical specifications of the interface, bus timing is included.

The STD 32 bus defines an 8bit, 16 bit or 32bit data bus, with a 16bit address bus. An additional 8 bits of address lines [for a total of 24bits] are multiplexed onto the lower order data lines [D0 - D7]. Termination resistors are required, the value of the termination resistor varies with the pin function. Diode termination may also be used if required at both ends of the backplane.
The specifications defines 136 signals; 117 data and control lines, with the rest power and ground lines. All lines are TTL compatible.

STD32 Card

The card size is defined as 4.5" x 6.5". Board thickness is 0.062". Board-to-Board spacing on the backplane is 0.0625", or 0.50" if you want to be compatible with STD-80. It's hard to go wrong with this board specification, every thing is covered. The specification is out dated, and is not being used for new designs. The STD32 interface is obsolete. Use the Buses icon at the bottom of the page to locate current bus interfaces in the same form factor. The STD Bus preceded the STD 32 Bus.

STD 32 Bus Standards Information

STD 32 Bus Specification and Designers Guide; Version 2.1, July 3, 1996

STD 32 Bus Interface IC Vendors

STD 32 bus uses normal [+5 volt] standard TTL switching levels.
V_IH = 2v, V_OH = 2.4v.

TTL glue logic IC Manufacturers
IC Manufacturers {All other styles}

STD32 Board Manufacturers

STD32 card manufacturers are shown below.

Micro/Sys
{Computer; 486DX/66-133, 386SX/25, 8/16-bit STD memory, Analog I/O, Timer, Digital I/O, Extender board, Prototyping board}

VersaLogic Corp.

Win Systems
{Single Board Computers, Memory Expansion Cards, Disk Controllers/Mass Storage, Video/Graphics Controllers,
Networking/Communications Controllers, Serial and Parallel I/O, Analog I/O, Special Function Cards, Accessories, Card Cages}

The vendor links were removed because of the age of the interface bus
The odds of a purchase diminish after 15 years, but the products do exist.

At this point in time the STD 32 Bus [STD32] would be considered obsolete, or at least out dated.
Many other backplane interfaces have come on the market over the last 20 years.
However, some companies can't afford to replace gear until it no longer functions.
In those cases the STD32 card would be considered a legacy product to be designed around, Out-of-Date or not.
In any case STD32 is an obsolete electrical interface and should not be used on a new card design.
The copper fingers used for board to board mating on STD32 is also dated, as is the TTL signaling.

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