Abstract: A card edge connector for printed circuit boards is disclosed which employs a double-decker design. The connector may have the same length and width as conventional connectors used on Industry Standard Architecture (ISA) personal computers but is deeper. Conventional 8- and 16-bit ISA accessory circuit boards may be plugged into a corresponding socket which is also disclosed herein until they reach a stop upon which they rest, working as they would in an ISA personal computer. 32-bit Extended Industry Standard Architecture accessory circuit boards have a second row of connectors and a notch so they slide farther down into the socket, lining up with a second row of contacts. This design uses less physical space for connectors, allowing more room for logic circuitry on the motherboard.

Abstract: A card edge connector for printed circuit boards is disclosed which employs a double-decker design. The connector may have the same length and width as conventional connectors used on Industry Standard Architecture (ISA) personal computers but is deeper. Conventional 8- and 16-bit ISA accessory circuit boards may be plugged into a corresponding socket which is also disclosed herein until they reach a stop upon which they rest, working as they would in an ISA personal computer. 32-bit Extended Industry Standard Architecture accessory circuit boards have a second row of connectors and a notch so they slide farther down into the socket, lining up with a second row of contacts. This design uses less physical space for connectors, allowing more room for logic circuitry on the motherboard.

Abstract: A memory expansion board capable of holding up to 16 Mbytes of memory devices, using primarily 1 Mbit chips, in 2 Mbyte module increments, on a single IBM PC/AT compatible size board. The circuit board is so designed that when the memory expansion board is populated by modules and placed in a computer system it does not interfere with any of the other expansion slots within the computer system, all of the expansion slots being normally spaced apart. The memory expansion board also includes a means of protecting the memory expansion board and modules from damage due to misalignment when inserting the board and/or modules. When certain of the modules are inserted rotated 180 degrees the circuit board cannot be properly installed in the system board because of physical interference. Lastly, the memory expansion board includes a means for providing reduced length addressing memory lines to memory devices appearing on opposite sides of a circuit board.

Abstract: The flip-flop circuit of the present invention is one that cannot glitch or enter a metastable hang-up state and has a probability of one of being completely settled at some given finite time following clocking. The flip-flop circuit is comprised of an input logic gate, an integrator and a logic latch circuit. In operation, the input logic gate changes state upon the coincidence of input signals, which change in state causes the integrator to change output level at a controlled rate. The latch circuit is sensitive to the output level of the integrator and changes state only when the integrator's output level reaches or exceeds preselected thresholds.