The 94228 is a main clock synthesizer chip for AMD-K7 based systems with VIA style chipset. This provides all clocks required for such a system. The 94228 belongs to ICS new generation of programmable system clock generators. It employs serial programming I2C interface as a vehicle for changing output functions, changing output frequency, configuring output strength, configuring output to output skew, changing spread spectrum amount, changing group divider ratio and dis/ enabling individual clocks. This device also has ICS propriety 'Watchdog Timer' technology which will reset the frequency to a safe setting if the system become unstable from over clocking.
- 1 - Differential pair open drain CPU clocks @ 2.7V
- 1 - Differential pair push-pull CPU clocks @ 2.5V
- 11 - PCI including 1 free running and 1 early @ 3.3V
- 1 - 48MHz, @ 3.3V fixed
- 1 - 24/48MHz @ 3.3V
- 3 - REF @ 3.3V, 14.318MHz.
- Programmable output frequency.
- Programmable output rise/fall time.
- Programmable slew and skew control for CPUCLK, PCICLK, AGP, REF, 48MHz and 24_48MHz.
- Real time system reset output.
- Spread spectrum for EMI control typically by 7dB to 8dB, with programmable spread percentage.
- Watchdog timer technology to reset system if over-clocking causes malfunction.
- Uses external 14.318MHz crystal.