CPU CONFIGURATION CONTROLLER Register/Multiplexer For Microprocessor VID

The Fairchild FM3570 replaces the CPU motherboards configu- ration switches with an electronic implementation consisting of a 4/5-bit multiplexed, 1-bit latched port, standard 2-wire bus inter- face, and non-volatile Latches The FM3570 multiplexes the I-port input signals with two internal non-volatile Registers that CAN be loaded through the serial port. The multiplexer is selected via the serial port and defaults to the I-port upon power-up. Pull-up resistors are provided on the input port to accommodate connections to open-drain outputs and to eliminate the need for external resistors. The device has open- drain outputs for easy Interface to devices with different VDD levels. By Fairchild Semiconductor