Pin Descriptions
LIST-XL Family
PIN DESCRIPTIONS
All signals are implemented in CMOS technology with TTL levels. Signal names that start with a slash (“/”) are active LOW.
Inputs should never be left floating. The CAM architecture draws large currents during compare operations, mandating the
use of good layout and bypassing techniques. Refer to the Electrical Characteristics section for more information.
/E (Chip Enable, Input, TTL)
/FF (Full Flag, Output, TTL)
The/EinputenablesthedevicewhileLOW. Thefallingedge
registersthecontrolsignals/Wand/CM.Therisingedgeturns
off the DQ pins and clocks the Destination and Source
Segment counters. The four cycle types enabled by /E are
shown in Table 2 on page 2.
The/FFoutputgoesLOWwhennoemptymemorylocations
exist within the device.
/RESET (Reset, Input, TTL)
/RESET must be driven LOW to place the device in aknown
state before operation, which will reset the device to the
conditionsshowninTable4onpage8.The/RESETpinshould
be driven by TTL levels, not directly by an RC time-out. /E
must be kept HIGH during /RESET.
/W (Write Enable, Input, TTL)
The/Winputselectsthedirectionofdataflowduringadevice
cycle. /W LOW selects a Write cycle and /W HIGH selects
a Read cycle.
VCC, GND (positive Power Supply, Ground)
ThesepinsarethepowersupplyconnectionstotheLISTXL.
VCC must meet the voltage supply requirements in the
OperatingConditionssectionrelativetotheGNDpins,which
are at 0 Volts (system reference potential), for correct
operation of the device. All the ground and power pins must
beconnectedtotheirrespectiveplaneswithadequatebulkand
highfrequencybypassingcapacitorsincloseproximitytothe
device.
/CM (DATA/Command Select, Input, TTL)
The /CM input selects whether the input signals on DQ15-0
are data or commands. /CM LOW selects Command cycles
and /CM HIGH selects Data cycles.
/DQ15-0 (Data Bus, I/O, TTL)
The DQ15-0 lines convey data, commands, and status to and
from the LIST-XL. /W and /CM controls the direction and
nature of the information that flows to or from the
device.When /E is HIGH, DQ15-0 go to Hi-Z.
/MF (Match Flag, Output, TTL)
The /MF output goes LOW when one or more valid matches
occur during the current or most recent compare cycle. /MF
isHIGHifthereisnomatch./MFwillberesetwhentheactive
configuration register set is changed.
/MM (Device Multiple Match Flag, Output, TTL)
The /MM output is LOW when more than one valid match
occurs during the current or the most recent compare cycle.
/MM will be reset when the active register set is changed.
Rev. 3.1
3
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