Abstract: A system management module (SMM) for a host server system includes a system management processor (SMP) connected to a system management local bus. The system management local bus connects to the system PCI bus through a system management central (SMC). The SMC includes the main arbitration unit for the PCI bus and also includes the arbiter for the system management local bus. The SMM includes a video controller and/or keyboard and mouse controller connected to the system management local bus to support remote consoling of the SMM. The SMC includes logic to monitor PCI cycles and to issue error signals in the event of a system error. The SMC also isolates failed components by masking request, grant and interrupt lines for the failed device. Further, if a spare component is provided, the SMC permits dynamic switching to the spare.

Abstract: A computer system includes a touchpad with one or more overlays providing the computer system with various input control functions. The overlay preferably includes tactile response elements to provide tactile feedback to the operator as an indication that a portion of the overlay has been pressed. The touchpad includes a capacitive sensor. Electronics coupled to the touchpad determine which portion of the touchpad sensor surface area has been touched or pressed. The amount of tactile feedback to the computer operator can be varied through the design and construction of the overlay and the overlay may be provided with no tactile feedback, if desired. As such, numerous overlays can be placed on the touchpad of the computer system, thereby providing the computer system with multiple different input control functions. The computer operator may manually input the type of overlay being used into the computer.

Abstract: A computer system including a modular keyboard assembly allows input device modules to be inserted into the keyboard assembly. The modular keyboard assembly includes a plurality of recessed opening in which an input device module can be inserted. A connector on the input device module mates with a connector in the recessed opening, thereby providing electrical contact between the input device module and the keyboard assembly. Each input device module can be replaced by the user with a different input device module providing flexibility to the user as well as minimizing the amount of cabling that typically confronts the user. A controller in the keyboard assembly determines the types of input device modules coupled to the keyboard assembly.

Abstract: A system management module (SMM) for a host server system includes a system management processor (SMP) connected to a system management local bus. The system management local bus connects to the system PCI bus through a system management central (SMC). The SMC includes the main arbitration unit for the PCI bus and also includes the arbiter for the system management local bus. The SMM includes a video controller and keyboard and mouse controller connected to the system management local bus to support remote consoling of the SMM. The SMC includes logic to monitor PCI cycles and to issue error signals in the event of a system error. The SMC also isolates failed components by masking request, grant and interrupt lines for the failed device. Further, if a spare component is provided, the SMC permits dynamic switching to the spare.

Abstract: A technique for reducing skew between clock signals in a digital system requiring multiple clock signals. The system preferably is implemented on a printed circuit board. An oscillator circuit provides a periodic signal to a clock buffer which generates multiple periodic clock signals. The clock signals are provided to various destination points on the printed circuit board. The rising and falling edges of each clock signal generated by the clock buffer do not occur precisely at the same time as the rising and falling edges of the other clock signals. This misalignment of clock edges, or skew, is detrimental to system performance, but is reduced substantially by connecting all of the clock buffer's output clock signals together at a single physical point or node. Accordingly, the printed circuit board traces carrying each of the clock signals are routed to a single point node. A single point node is used to reduce skew caused by the clock buffer.