GENERAL DESCRIPTION
The National Semiconductor PC8741x family of LPC ServerI/O devices (“PC8741x”) comprises highly integrated Advanced I/O products. Boot Flash and I/O devices can be accessed over this X-Bus. Embedded controllers can access the PC8741x and its X-Bus via the ACCESS.bus or SMBus serial interface when VSB exists, regardless of the LPC bus state. Some of the PC8741x logical devices can be disabled, or their pins can be floated, under control of the VSB-powered serial bus. The PC8741x provides a VSB-powered high-frequency clock for on-chip peripherals and for other VSB-powered platform components. The PC8741x’s extended wake-up support complements the chipset’s ACPI controller and the platform embedded controllers. The PC8741x can monitor the Power and Sleep buttons and control the power supply of simple platforms that lack an embedded controller. The System Wake-Up Control (SWC) module is powered by VSB and VBAT power supplies. It sup® ports flexible wake-up and power-off request mechanisms in any sleep state.