SMSC COM20020 Operational Description, Maximum Guaranteed Ratings, DC Electrical Characteristics

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OPERATIONAL DESCRIPTION

MAXIMUM GUARANTEED RATINGS*
Operating Temperature Range	0oC to +70oC
Storage Temperature Range	-55oC to +150oC
Lead Temperature (soldering, 10 seconds)	+325 oC
Positive Voltage on any pin, with respect to ground	VDD+0.3V
Negative Voltage on any pin, with respect to ground	-0.3V
Maximum VDD	+7V

*Stresses above those listed may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other condition above those indicated in the operational sections of this specification is not implied.

NOTE: When powering this device from laboratory or system power supplies, it is important that the Absolute Maximum Ratings not be exceeded or device failure can result. Some power supplies exhibit voltage spikes or "glitches" on their outputs when the AC power is switched on or off. In addition, voltage transients on the AC power line may appear on the DC output. If this possibility exists it is suggested that a clamp circuit be used.

DC ELECTRICAL CHARACTERISTICS

VDD=5.0V±10%

COM20020: TA=0oC to +70oC, COM20020I: TA=-40oC to +85oC

PARAMETER	SYMBOL	MIN	TYP	MAX	UNIT	COMMENT

Low Input Voltage 1	VIL1			0.8	V	TTL Levels
(All inputs except A2,
XTAL1, nRESET, nRD,
nWR, and RXIN) High
High Input Voltage 1	VIH1	2.0			V	TTL Levels
(All inputs except A2,
XTAL1, nRESET, nRD,
nWR, and RXIN)

Low Input Voltage 2	VIL2			1.0	V	TTL Clock Input
(XTAL1)
High Input Voltage 2	VIH2	4.0			V
(XTAL1)

Low to High Threshold	VILH		1.8		V	Schmitt Trigger,
Input Voltage (A2,						All Values at VDD =
nRESET, nRD, nWR,						5V
RXIN)
High to Low Threshold	VIHL		1.2		V
Input Voltage (A2,	VIHL		1.2		V
Input Voltage (A2,
nRESET, nRD, nWR,
RXIN)

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Contents General Description FeaturesTable of Contents PIN Configuration A1,A2/ALE Description of PIN FunctionsTransmission Media Interface DIP PIN Plcc PIN Name Symbol DescriptionMiscellaneous Instead, it must be connected to XTAL1 with COM20020 Operation Data Rates Network ReconfigurationProtocol Description Network ProtocolBroadcast Messages Extended Timeout FunctionResponse Time Invitations To Transmit Reconfiguration TimeIdle Time Line ProtocolAcknowledgements Data PacketsNegative Acknowledgements System Description MULTIPLEXED, 8051-LIKE BUS Interface with RS-485 Interface Figure C Traditional Hybrid Interface Backplane ConfigurationCOM20020 Network Using RS-485 Differential Transceivers Programmable Txen Polarity Differential Driver ConfigurationInternal Block Diagram Cable Type Impedance AT 5MHZ Functional DescriptionAttenuation NominalRead Register Summary Write Tentative ID Register Internal RegistersInterrupt Mask Register IMR Data RegisterStatus Register Diagnostic Status RegisterCommand Register Next ID RegisterConfiguration Register Setup Register BIT BIT Name Symbol Description Dupid BIT BIT Name Symbol DescriptionData Command Description Address Pointer Low Register Address Pointer High RegisterReset Configuration RegisterCKP3 CKP2 CKP1 Sequential Access Operation Software Interface Sequential Access MemoryAccess Speed Internal RAMTransmit Sequence Selecting RAM Page SizeRAM Buffer Packet Configuration Page Receive Sequence Transmit Command Chaining Command ChainingReceive Command Chaining Internal Reset Logic Reset DetailsInitialization Sequence Improved DiagnosticsAbnormal Results Normal ResultsOscillator Operational Description Maximum Guaranteed RatingsDC Electrical Characteristics Parameter Symbol MIN TYP MAX Unit CommentXTAL1, XTAL2 Input Capacitance Multiplexed BUS, 68XX-LIKE Control Signals Read Cycle Timing DiagramsMultiplexed BUS, 80XX-LIKE Control Signals Read Cycle Multiplexed BUS, 68XX-LIKE Control Signals Write Cycle Multiplexed BUS, 80XX-LIKE Control Signals Write Cycle NON-MULTIPLEXED BUS, 80XX-LIKE Control Signals Read Cycle NON-MULTIPLEXED BUS, 68XX-LIKE Control Signals Read Cycle NON-MULTIPLEXED BUS, 80XX-LIKE Control Signals Write Cycle NON-MULTIPLEXED BUS, 68XX-LIKE Control Signals Write Cycle These signals are to and from the hybrid Normal Mode Transmit or Receive TimingNTXEN NPULSE1 TTL Input Timing on XTAL1 PIN 28-PIN Plcc Package Dimensions 24-PIN DIP Package Dimensions SECTION/FIGURE/ENTRY Correction Revised DateStandard Microsystems Corp