Patent GB-1054358-A (GB)
IPC: H03K17/81
Abstract: 1,054,358. Circuits ;mploying bi-stable magnetic cores. HONEYWELL Inc. Aug. 17, 1965 [Aug. 18, 1964], No. 35284/65. Heading H3B. [Also in Division G4] A signal buffer for connection between a signal processor in a computer and its input and output devices consists of a plurality of groups of magnetic cores, all the cores being linked by a common drive winding and a common reset winding, an individual sensewinding linked with each core, and a plurality of inhibit windings selectively linked with the cores and arranged for selective energization to prevent selected cores from being switched by energization of the drive winding. In Fig. 1 (not shown), a first group of cores couples the processor to a digital output circuit, a digitalanalogue converter and a digital input to an operator's console, a second group couples the processor to digital input circuits, a pulse input circuit and an input from the operator's console, a third group couples the processor to a control circuit for a pair of stepping motors, and a fourth group couples the processor to a digital typewriter, an analogue selector controlling an analogue input multiplexor and a digital selector controlling an output multiplexor. In the first group (Fig. 2, not shown), four inhibit conductors 43, 44, 46, 47 are each linked to a different pair of cores so that selection of a pair of inhibit conductors inhibits all cores but one. Sense amplifiers 50 connected to the respective sense windings on the cores are strobed to respond only to switching of a core by a driving pulse and not by a resetting pulse. The inhibit windings to be energized are selected by digital signals from the processor. Each core in the second group (Fig. 3, not shown), has an individual inhibit winding, energization of which is controlled by a switch 60, and a further inhibit winding 65 common to all cores of the group is also provided. An inhibit winding 64 links none of the cores of the group and is provided for linking with cores of another group. The group in use is selected by selective energization of windings 64 and 65 and a core in the group is selected by closing a selection of switches 60. The outputs from the sense amplifiers 66 are transferred to a digital storage register for subsequent transfer to the processor. The direction of rotation of a stepping motor is controlled by a pair of cores forming the third group. Four inhibit windings are provided, one being linked to each core, one linking both cores and one linking neither core. The latter winding may link a second pair of cores forming another group for controlling a second motor. The sense windings on the two cores are oppositely wound so that an output of one or the opposite polarity is fed to the motor control circuit depending on which core is selected. The fourth group, Fig. 5, has inhibit windings 80, 81, 82, 83 selected by digital signals from the processor, and the sense windings each control the firing of a silicon controlled rectifier 90. When fired, each SCR allows energization of a column of a matrix including relay coils 86 and diodes 91. A row is selected by transistors 87, 88. The relay coils may control stepping of a multiplexor or may actuate typewriter keys. The drive, reset and inhibit windings for the groups of cores form parts of a bus connected between the processor and a timing circuit.