Abstract: A method and apparatus for performing cache snoop testing on personal computers using software to initiate DMA cycles. The computer system includes an extended capabilities parallel port (ECP), which includes a 16 bit first-in first-out buffer (FIFO) that can be accessed in a test mode where software can manually write and read the FIFO. This FIFO in the ECP parallel port is used according to the present invention to implement cache snoop testing diagnostics on personal computers. In the preferred embodiment, various hardware subsystems such as system memory, the ECP port, and the DMA controller are tested first to ensure that, if a failure occurs during cache testing, the system can differentiate between cache snoop failures and other subsystem failures. Cache snoop testing according to the present invention uses the capability provided by the ECP parallel port to generate DMA cycles which transfer data from the ECP FIFO buffer into the system memory via software.

Abstract: In a computer system having a computer bus drive circuit capable of providing drive current to an individual line of a computer bus coupled thereto, a circuit for determining a proper level for the drive current and a method of making such determination. The circuit comprises: (1) a detection circuit, coupled to the individual line of the bus, for monitoring a response of the individual line of the bus to changes in state thereof during an operation of the computer system and providing an indication of the response and (2) a drive current establishment circuit, coupled between the detection circuit and the computer bus drive circuit, for establishing the proper level for the drive current in response to the indication produced by the detection circuit during an operation of the computer system.

Abstract: A specially designed metal grounding cap is placed over a metal-plated housing boss upon which a printed circuit board is to be mounted by extending a screw through a hole in the circuit board and tightening the screw into a metal insert previously forced into the free end of the mounting boss. As the screw is tightened into the boss insert, an EMI grounding pad on the underside of the circuit board engages an end wall of the grounding cap and pushes it into forcible engagement with the inner end of the boss. The forcible engagement of the grounding cap end wall causes leg portions of the cap to pivot inwardly and engage portions of the plated boss side wall between the boss insert and the metal plated housing wall from which the boss inwardly projects.

Abstract: Disclosed are a personal digital assistant ("PDA") and a method of providing data to the PDA. The PDA includes: (1) a chassis having first and second noncoplanar surfaces thereon and containing computer processing circuitry therein, (2) a visual display located on one of the first and second surfaces, the visual display coupled to the circuitry to allow the circuitry to drive the visual display and (3) a plurality of momentary keys located on both of the first and second surfaces and coupled to the circuitry, the plurality cooperating to form a chord keyboard to thereby allow multiple ones of the plurality to be depressed at a time to form a chord, the circuitry interpreting the chord as a single keystroke.

Abstract: A system for automatically adapting the power conservation functions of a personal computer (PC) to the work patterns of any user. A power control system of the PC monitors activity of I/O devices and if upon the elapse of a first time interval a particular I/O device or combination of devices has not been accessed, one or more I/O devices are powered-down. Following power-down, the first time interval is incrementally increased if I/O activity immediately occurs thereafter, prior to elapse of a second time interval. This process may repeat itself several times until the first time interval reaches a maximum value. Alternatively, if, following power-down, I/O activity does not occur until after elapse of a third time interval, the first time interval is incrementally decreased until the first time interval reaches a minimum value. The system thereby automatically adapts to maximize power conservation during periods of low activity while preventing user disruption during periods of increased activity.

Abstract: Disclosed are a system and method for loading diagnostic routines images from disk for execution in a computer system. The method comprises the steps of (1) executing a boot loading routine stored in non-volatile memory within the computer system, the boot loading routine providing an environment in lieu of an operating system of the computer system within which to execute diagnostic routines, the boot loading routine including a disk access routine, (2) retrieving a diagnostic routine stored as an image on a disk into video random access memory ("RAM") with the disk access routine and (3) executing the retrieved diagnostic routine under control of the boot loading routine. The present invention, in its preferred embodiment, allows relatively large diagnostic routines to be stored in the form of images on a disk drive in the computer system and retrieved, as required, into video RAM for execution, without requiring the computer's operating system to function.