IMISC670 - International Microcircuits

IMISC670 I2C Clock Generator

Xin, Xout - These pins form an on-chip reference oscillator when connected to terminals of an external parallel resonant crystal (nominally 14.318 MHz). Xin may also serve as input for an externally generated reference signal. SEL - Standard frequency select input. It has internal pull-up. CPUCLK(0:3) - Low skew (<250 pS) clock outputs for host frequencies s.

Features

SEL FREQUENCY TABLE CPU 60.0 66.6 PCI 30.0 33.3 0 1
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• Supports Pentium & Pro CPUs. 4 CPU clocks up to 8 loads. Up to 8 SDRAM clocks for 2 DIMs. Supports Power Savings Frequencies. 7 PCI synchronous clocks. Optional common or mixed supply mode: (Vdd = Vddq3 = Vddq2 = 3.3V) or (Vdd = Vddq3 = 3.3V, Vddq2 = 2.5V) < 250ps skew CPU and SDRAM clocks. < 250ps skew among PCI clocks. I2C 2-Wire serial interface Programmable registers featuring: - enable/disable each output pin - mode as tri-state, test, or normal - 24/48 MHz selections 1 IOAPIC clock for multiprocessor supp.