ICS9248-195 Datasheet, PDF (13/16 Pages) Integrated Circuit Systems – Frequency Generator & Integrated Buffers for PENTIUM II/III & K6

ICS9248 - 195
CLK_STOP# Timing Diagram
CLK_STOP# is an asychronous input to the clock synthesizer. It is used to turn off the CPU clocks for low power
operation.CLK_STOP# is synchronized by the ICS9248-195.The minimum that the CPU clock is enabled (CLK_STOP#
high pulse) is 100 CPU clocks. All other clocks will continue to run while the CPU clocks are disabled.The CPU clocks
will always be stopped in a low state and start in such a manner that guarantees the high pulse width is a full pulse.
CPU clock on latency is less than 4 CPU clocks and CPU clock off latency is less than 4 CPU clocks.
INTERNAL
CPUCLK
PCICLK
CLK_STOP#
PCI_STOP# (High)
SDRAM
CPUCLK
CPUCLK _F
SDRAM_F
Notes:
1. All timing is referenced to the internal CPU clock.
2. CLK_STOP# is an asynchronous input and metastable conditions may exist. This signal is
synchronized to the CPU clocks inside the ICS9248-195.
3. SDRAM-F output is controlled by Buffer in signal, not affected by the ICS9248-195
CLK_STOP# signal. SDRAM are controlled as shown.
4. All other clocks continue to run undisturbed.
0375D—02/02/04
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