ICS950810 Datasheet, PDF (15/19 Pages) Integrated Circuit Systems – Frequency Generator with 200MHz Differential CPU Clocks

ICS950810
CPU_STOP# - Assertion (transition from logic "1" to logic "0")
The impact of asserting the CPU_STOP# pin is all CPU outputs that are set in the I²C configuration to be stoppable via
assertion of CPU_STOP# are to be stopped after their next transition. When the I²C Bit 6 of Byte 1 is programmed to '0'
the final state of the stopped CPU signals is CPU = High and CPU# = Low. There is to be no change to the output drive
current values. The CPU will be driven high with a current value equal to (Mult 0 'select') x (Iref), the CPU# signal will not
be driven . When the I²C Bit 6 of Byte 1 is programmed to '1' then final state of the stopped CPU signals is Low, both CPU
and CPU# outputs will not be driven.
Assertion of CPU_STOP# Waveforms
CPU_STOP#
CPUT
CPUC
CPU_STOP# Functionality
CPU_STOP#
1
0
CPUT
Normal
iref * Mult
CPUC
Normal
Float
CPU_STOP# - De-assertion (transition from logic "0" to logic "1")
All CPU outputs that were stopped are to resume normal operation in a glitch free manner. The maximum latency from the
de-assertion to active outputs is to be defined to be tetween 2 - 6 CPU clock periods (2 clocks are shown). If the I2C Bit
6 of Byte 1 is programmed to "1" then the stopped CPU outputs will be driven High within 3 nS of CPU_Stop# de-assertion.
De-assertion of CPU_STOP# Waveforms
0472F—01/12/04
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