SMC Networks SMC91C95 guide

Reverse Polarity Function

In the 10BASE-T mode, the PHY monitors for receiver polarity reversal due to crossed wires and corrects by reversing the signal internally.

Collision Detection Function

In the 10BASE-T mode, while in half duplex, a collision state is indicated when there are simultaneous transmissions and receptions on the twisted pair link. During a collision state, the nCOLL signal is asserted. If the received data ends and the transmit control signal is still active, the transmit data is sent to the MAC within 9 bit times. The nnCOLL signal is de- asserted within 9 bit times after the collision terminates. In the AUI mode, the external

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transceiver sends a 10MHz signal to the PHY upon detection of a collision.

Link Integrity

The PHY test for a faulty twisted-pair link. In the absence of transmit data, link test pulses are tranmsitted every 16+/-18ms after the end of the last transmission or link pulse on the twisted pair medium. If neither valid data nor link test pulses are received within 10 to 150ms, the link is declared bad and both data transmission as well as the operational loopback function are disabled. The Link Integrity function can be disabled for pre- 10BASE-T twisted-pair networks.

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SMC Networks SMC91C95 manual

Contents

Bus Interface Features Table of Contents PIN Configuration Network InterfaceSoftware Drivers Overview General DescriptionPage Uses non-volatile jumperless setup via serial Eeprom ISAPcmcia PIN Requirements Function ISA Pcmcia Number Pins Coln Crystal OSC XTAL1 XTAL2 Power VDD Avdd Ground GNDTotal Pins Recp Description of PIN Functions PIN no Name Symbol Type Description Reset ISA Byte High Enable input. Asserted lowPcmcia Card Enable 2 input. Used to Enable Select card on odd byte accesses Ready Register. This interrupt is tri-stated when not Application of the VCC or Reset which everISA Output. Active high interrupt signal. Value of INT SEL1-0 bits in the Configuration Interrupt pin if enabled Whenever the SMC91C95 is in 16 bit modeEnable Function bit in the Ecor Is with Input. Active low read strobe used to access Pin when enabled by the Audio bit Modem Pin is active high when either the PwrdwnOutput B Powerdown mode Pwrdwn bit is zero Value of the Mringin input. When entering Sdout Eeprom Eeprom EeskEeprom Eecs Eeprom Eedo AUI RxclkTXD Register Tperxn TPE Tpetxp TPE TpetxdpTxclk Buffer Types EndecVSS Avss SMC91C95 SMC91C95 SMC91C95 Internal Block Diagram Bus Transactions in ISA Mode NSBHE D0-D7 D8-D15 BIT ModeFunctional Description Even byte Bus Transactions in Pcmcia Mode NCE1 NCE2 D0-D7 D8-D15Even byte IOis8=1 + nEN16=1.16BIT=0 No Cycle Signals ISA Pcmci ON-CHIP Depth Width Used SMC91C95 Address SpacesROM Buffer Memory Mapping and Paging VS. Receive and TX Area CPU Side TX Fifo TX CompletionFifo Receive Queue and Mapping With Block DiagramSMC91C95 Internal Transmit Packet Receive Packet Packet Format in Buffer Memory ODD CRC ODDByte before the Control Byte should be ignored Address Hash Value Multicast Table BIT Receive Frame Status Word SMC91C95 Interrupt Merging Function Pcmcia Mode ISA ModeInterrupt Output NIREQ when either function is Interrupt Structure Mcor Reset LogicReset Functions Ecor Pwrdwn Powerdown LogicPowerdown Functions Powerdown Powers Does not Entered Exited Power Down Pcmcia Attribute Memory Address 0- 7FFEh Pcmcia Configuration Registers Address 8000-803Eh 7FFEh 8000h 803Eh Attribute Memory Address Using Serial Eeprom Offsetname ISA and Pcmcia ModeTypesymbol Space BANK0 BANK1 BANK2 BANK3 BANK4 BANK5 Internal I/O Space Mapping BS2 BS1 BS0 BANK# Bank Select Register Offset Name Type Symbol READ/WRITE BSRHigh Byte LOW BS2 BS0 LOW Pade Forco Loop Txena Byte High Fdse EPH STP Fdupl MON Nocrc Byte Loop Sqet AUI Fdse Fduplx Ephloop Loop Loops AT Network Transmits LTX MUL High Link CTR EXC Lost Latcol Wakeu ByteOvrn Carr LOW LTX SqetPage Rxabort Rxovrnint High SoftStrip Rxen Byte RST CAR LOW Almul Prms Byte AbortPage FFH Memory Size Actual Memory Register Device Space BANK0 Offset Name Type Symbol Memory ConfigurationMCR Register READ/WRITE INT Byte High Full SET AUI Byte Wait StepSelec DIS INT SEL1 INT SEL0 Interrupt PIN Used RA15 RA14 A15 A14 A13Byte LOW ROM Size RA17 High Address Byte LOW High Byte LOW Byte High Data Byte LOW Data Byte Release LOW Eeprom Reload Store Byte Enable High RCVWakeu Auto Byte BAD Pcmcia Eeprom to Sram Memory Map 3FF 3FA3FC 3FD 000 0 Noop no Operation High Byte LOW Command N0/BUSCommand SET xyz Busy Bit Readable Command Sequencing Failed Allocated Packet Number This register is updated upon an Allocate Memory MMU commandPage Page Space BANK2 Offset Name Type Symbol Through AhData Register READ/WRITE Data High Data LOW Ercv INT Rxovr Empty TX INT Ercv EPH INT Rxovr Alloc TX INT RCV INT EmptyPage INT LOW Multicast Table Byte High Bit MDO NXNDEIOS2 IOS1 IOS0 Byte LOW Mdoe Mclk MDI MDO MDOE=0 MDOE=1 Chip ID Value Device High Byte LOW Byte Chip REV Byte Discr High Byte LOW RCV Theory of Operation Memory ArchitectureFull Duplex Ethernet Support Main 802.3 section affected by Fdse is Behavior in Fdse Mode Typical Flow of Events for Transmit Driver CSMA/CD Side Typical Flow of Events for Receive Driver CSMA/CD Side Ethernet Interrupt Service Routine MMU RAM CSMA/CD RX Intr Assumes Auto Release Option Selected TX Intr Txempty Intr Driver Send and Allocate Routines Interrupt Generation Memory Partitioning Internal VS. External Attribute Memory MAP Attribute Memory Decodes Using Serial Eprom Ireq Pcmcia Configuration Registers DescriptionSreset Wrattri IOIs8 8002h Ethernet Configuration and Status Register EcsrPage Pcmcia functionality, this bit must be set LevIREQ Enable IOIs8 Reserved Audio Current Value Value Written NEW Value 8024h Pin Replacement Register PRR 8028h Extended Status RegisterESR Ringevent Ringenable A15 A14 A13 A12 A11 A10 802Ah Modem I/O Base Register 802Ch Modem I/O Base Register 8032h Modem I/O Size Register Functional Description of the Blocks Memory Management UnitArbiter Wait State Policy BUS Interface DMA Block Packet Number Fifos MMU Packet Number Flow and Relevant Registers DMA Csma Block Physical Interface Network Interface10BASE-T AUI Transmit Functions Receive Functions Page Register Address Board Setup Information ISA ModeEthernet Individual Address I/O Base Address Eeprom Word Arbitration Considerations Diagnostic LEDsPage 103 64 X 16 Serial Eeprom MAP for ISA Mode Maximum Guaranteed Ratings Operational DescriptionParameter Symbo MIN TYP MAX Units Comments Type Buffer Input LeakageIP Type Buffers ID Type Buffers Limits Parameter Symbo MIN TYP MAX Unit Test Condition OD16 Type BufferOD162 Type Buffer OD24 Type Buffer Parameter MIN TYP MAX Units Capacitive Load on OutputsINTRO-INTR3 108 Timing DiagramsA50, nREG NCE1 NOE D150 30 max Max Min Data Valid Address/nREG Setup Time to NWE Low NWE High NCE1 Low to nWE High Setup109 110 O Read Timing Table on the following Parameter Min Typ Max Units 112 O Write Timing Table on the following 100 114 Card Configuration Registers READ/WRITE Pcmcia Mode A15=1 115 NINPAC 116 Consecutive Pcmcia Write Cycles 117 Pcmcia Attribute Memory READ/WRITE A15=0 118 Mringoutb 119 ISA Consecutive Read Cycles 120 ISA Consecutive Write Cycles 121 ISA Consecutive Read and Write Cycles 122 Data Register Special Read Access 123 Data Register Special Write Access 124 BIT Mode Register Cycles 125 ISA Register Access When Using Bale 126 External ROM Read Access Using Bale 127 Eeprom Read 128 Eeprom Write 129 Memory Read Timing 130 External Endec Interface Start of Transmit 131 Differential Output Signal Timing 10BASE-T and AUI Tperxpn Recp Recn Tperxp Tperxn Recp Recn 134 Transmit Timing END of Frame AUI and 10BASE-T 135 Collision Timing AUI 136 Vtqfp Package OutlinePage Kennedy Drive Hauppauge, NY 516 435-6000 FAX 516