Abstract: An apparatus and method for tracking and interception of instructions as they are presented to the memory, selectively passing harmless data to the device and disallowing the sequences which instruct the device to perform harmful functions, such as self-erase. A software trap is provided to be transparent to the operation of the device and the host system, imposing no harmful timing delays or software overhead. Accordingly, the invention allows the use of standard electrically erasable read-only memories in an application which requires that the device be protected from global erasure. A hardware front end intercepts the software command which is used to globally erase the device.

Abstract: A method and circuit for relatively accurately measuring the die temperature of an IC, such as a microprocessor, by sensing one or more internal circuit elements which have an electrical parameter which varies as a function of temperature, such as an input protection diode. By sensing the one or more circuit elements which have an electrical parameter that is temperature dependent, the method provides a relatively more accurate measurement of the die temperature than measuring the outside temperature of the IC package. In addition, a control circuit is provided for cooling the IC during excessive temperature conditions by slowing down the clock frequency of the IC until the die temperature is within the temperature limit in order to optimize the utility of the IC during excessive temperature conditions.

Abstract: A relatively fast system control processor, such as an Intel 8051, is substituted for an Intel 8042 microprocessor in a PC/AT type compatible personal computer. In one embodiment of the invention, a System Control Processor Interface (SCPI) is provided between the central processing unit (CPU) and the system control processor (SCP) to maintain compatibility with the PC/AT bus. The combination of the faster SCP and the SCPI interface improves the overall system performance. Control circuitry is also provided for setting the A20 signal relatively quickly to allow memory access above one megabyte. In an alternate embodiment of the invention, a Mouse Keyboard Interface (MKI) is provided. The MKI provides even quicker switching of the Gate A20 signal by eliminating the need to interrupt the SCP. The MKI also provides support for a type PS/2 mouse.

Abstract: A plurality of processors form a network used to communicate with one or more peripheral devices and the system control processor. One processor is dedicated to at least one peripheral device. Since the system control processor is not burdened with the relatively slow communications protocol with the peripheral devices, it is free to do other tasks which improves the overall system performance. Communication protocol between the dedicated processors allows for local and global communication.

Abstract: A relatively fast system control processor, such as an Intel 8051, is substituted for an Intel 8042 microprocessor in a PC/AT type compatible personal computer. In one embodiment of the invention, a System Control Processor Interface (SCPI) is provided between the central processing unit (CPU) and the system control processor (SCP) to maintain compatibility with the PC/AT bus. The combination of the faster SCP and the SCPI interface improves the overall system performance. Control circuitry is also provided for setting the A20 signal relatively quickly to allow memory access above one megabyte. In an alternate embodiment of the invention, a Mouse Keyboard Interface (MKI) is provided. The MKI provides even quicker switching of the Gate A20 signal by eliminating the need to interrupt the SCP. The MKI also provides support for a type PS/2 mouse.