Mcr, Register READ/WRITE, Device | SMC Networks SMC91C95 specification

I/O SPACE - BANK0
OFFSET	NAME	TYPE	SYMBOL
A	MEMORY CONFIGURATION	Lower Byte -	MCR
	REGISTER	READ/WRITE
		Upper Byte -
		READ ONLY

HIGH BYTE

LOW BYTE

				MEMORY SIZE MULTIPLIER

0	0	1	1	0	0	1	1
	MEMORY RESERVED FOR TRANSMIT (IN BYTES * 256 * M)

0	0	0	0	0	0	0	0

MEMORY RESERVED FOR TRANSMIT - Programming this value allows the host CPU to reserve memory to be used later for transmit, limiting the amount of memory that receive packets can use up.

When programmed for zero, the memory allocation between transmit and receive is completely dynamic.

When programmed for a non-zero value, the allocation is dynamic if the free memory exceeds the programmed value, while receive allocation requests are denied if the free memory is less or equal to the programmed value.

This register defaults to zero upon reset. It is not affected by the RESET MMU command.

The value written to the MCR is a reserved memory space IN ADDITION TO ANY MEMORY CURRENTLY IN USE. If the memory allocated for transmit plus the reserved space for transmit is required to be constant (rather than grow with transmit allocations) the CPU should update the value of this register after allocating or releasing memory.

The contents of MIR as well as the low byte of MCR are specified in 256 * M bytes. The multiplier M is determined by bits 11,10, and 9 as follows. Bits 11,10 and 9 are read only bits used by the software driver to transparently run on different controllers of the SMC9000 family.

DEVICE	bit 11	bit 10	bit 9	M	MAX MEMORY SIZE

FEAST	0	1	0	2	2562562=128k

SMC91C90	0	0	1	1	2562561=64k
FUTURE	0	1	1	4	256k

FUTURE	1	0	0	8	512k
FUTURE	1	0	1	16	1M

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Image 47

SMC Networks SMC91C95 manual Space BANK0 Offset Name Type Symbol Memory Configuration, Mcr, Register READ/WRITE, Device

Contents

Bus Interface Features Table of Contents Software Drivers PIN ConfigurationNetwork Interface Overview General DescriptionPage Pcmcia Uses non-volatile jumperless setup via serial EepromISA 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 Txclk Tperxn TPE TpetxpTPE Tpetxdp Buffer Types EndecVSS Avss SMC91C95 SMC91C95 SMC91C95 Internal Block Diagram Functional Description Bus Transactions in ISA Mode NSBHE D0-D7 D8-D15BIT Mode Even byte Bus Transactions in Pcmcia Mode NCE1 NCE2 D0-D7 D8-D15Even byte IOis8=1 + nEN16=1.16BIT=0 No Cycle ROM Signals ISA Pcmci ON-CHIP Depth Width UsedSMC91C95 Address Spaces Buffer Memory Mapping and Paging VS. Receive and TX Area Fifo CPU Side TX FifoTX Completion Receive Queue and Mapping With Block DiagramSMC91C95 Internal Transmit Packet Receive Packet Packet Format in Buffer Memory Byte before the Control Byte should be ignored ODD CRCODD 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 Wakeu Auto Byte BAD Release LOW Eeprom Reload Store Byte EnableHigh RCV 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 Data Register READ/WRITE Data High Data LOW Space BANK2 Offset Name Type SymbolThrough Ah 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 Full Duplex Ethernet Support Theory of OperationMemory Architecture 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 Arbiter Functional Description of the BlocksMemory Management Unit 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 Parameter Symbo MIN TYP MAX Units Comments Maximum Guaranteed RatingsOperational Description 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 INTRO-INTR3 Parameter MIN TYP MAX UnitsCapacitive Load on Outputs 108 Timing DiagramsA50, nREG NCE1 NOE D150 30 max Max Min Data Valid 109 Address/nREG Setup Time to NWE LowNWE High NCE1 Low to nWE High Setup 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