Hewlett-packard Company

William E Egbert

Dale A Mack

Mark F Resman

The present invention provides a process for loading an off-board program into a computer peripheral apparatus connected to a host computer via a standard interface port. Random access memory of the peripheral apparatus is used by the host computer. The process includes the steps of: applying power to the apparatus, initializing the apparatus to achieve minimal operational conditions, polling the interface port for a signal indicative of a host computer to peripheral apparatus program download request. Upon receiving the download request, the peripheral apparatus configures the random access memory to receive the program via the interface port, then provides a signal indicative of readiness to receive the program. The program can then be downloaded from the host, received in the random access memory, and run. If the download request is not recognized, the apparatus is fully initialized to its normal state of readiness for receiving common commands from the host computer. Substantially the same process can be used for upgrading other programmable memories of computer peripheral apparatus.

Method for downloading special code from a computer to a hard copy

An adaptive method allocates RAM between procedures having both higher and lower priorities. The RAM is provided with first and second portions, the first portion for assignment to higher priority procedures and the second portion for assignment to lower priority procedures, higher priority procedures being able to access also the second portion of RAM. The adaptive method comprises the steps of: responding to a request for allocation of RAM to a higher priority procedure by determining if RAM is available from the first portion and, if not, allocating RAM from the second portion to the higher priority procedure. The method enables allocation of RAM from the second portion to a lower priority procedure when available RAM in the first portion exceeds a first threshold level. The system continues the enablement until the available RAM in the first portion falls below a lower, second threshold level at which point, the allocation of memory in the second portion of RAM to the lower priority procedure is inhibited. The inhibition of allocation of RAM from the second portion to a lower priority procedure continues until the available RAM in the first portion again exceeds the first threshold level.

Adaptive method for dynamic allocation of random access memory to

The pulse-width modulated motor speed control circuit described herein includes a binary latch-controlled motor driver, wherein the state of the controlling match is determined by the phase of the drive signal and the level of back emf of the motor when the motor is not being driven.

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Boise, ID, United States of America

William E Egbert