Importance

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Abstract

An apparatus to permit the sharing of interrupts between resident devices and removable PCMCIA peripherals overcomes a deficiency in the PCMCIA standards. By permitting interrupt sharing, the apparatus allows standard application software, which assumes the interrupt sharing capability of standard built-in peripherals to operate with PCMCIA cards. The invention is particularly suited to serial communication ports, where interrupts are routinely shared. An interface component 20 is coupled to an interrupt controller 12. A serial port COM1 is connected to a host interrupt IRQ4, which is shared by a PCMCIA card serial port 22, configured as COM3, through the interface controller 20. Through the use of an open-drain output and a conversion in the controller 20 of the level mode interrupt from the PCMCIA card to a low-going pulse of sufficient voltage swing and duration, the host interrupt is shared between the permanently installed COM1 and the removable COM3 serial ports.

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First Claim