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SMSC LAN91C111 9.4Releasing The Transmitted Packet, 9.5Receiving A Packet, 9.6Releasing A Received Packet

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SMSC LAN91C111 32/16/8-Bit Three-In-One Fast Ethernet Controller

** The packet will now be sent on the wire when the line is clear **

Poll for completion (<= 100ms)

Read the INTERRUPT register until bit 1 (TX INT) is set (bank 2, offset C) Read the status word of the packet

Write 0x6000 to the POINTER register (TX, RD, AUTOINC), (bank 2, offset 6) Read the DATA register (bank 2, offset 8) to get the Status Word of the packet

The Status Word will show any errors in transmission; it mirrors the EPH STATUS register (bank 0, offset 2)

9.4Releasing The Transmitted Packet

Write 0x00A0 to the MMUCOM register (bank 2, offset 0) to release the packet and its associated memory. Poll the BUSY bit (bit 0) of the MMUCOM register until it is clear to verify the operation is complete

It is recommended that the transmitted packet be released immediately after updating any statistics, to free up buffer memory. If the auto release feature is used, the MAC automatically releases the packet after transmission.

9.5Receiving A Packet

The following steps show the sequence to receive a packet.

Turn on the receiver

Write 0x0100 in the RCR register (bank 0, offset 4) Loop on RX INT until a packet is received

Read the INTERRUPT register (bank 2 , offset C) until bit 0 (RCV INT) is set Read the receive packet

The receive packet # will be at the top of the RX FIFO (bank 2, offset 4, high byte) if no previous packet was received

Set the POINTER register (bank 2, offset 6) for RCV, RD, AUTOINC Write 0xE000

Read the DATA register (bank 2, offset 8), successive word reads: Read the status word

Read the byte count

Read the destination address (bytes 10) Read the destination address (bytes 32) Read the destination address (bytes 54) Read the source address (bytes 10)

Read the source address (bytes 32) Read the source address (bytes 54) Read the packet size

Read the control word

9.6Releasing A Received Packet

Write 0x0080 to the MMUCOM register (bank 2, offset 0). This releases the packet number present in the RX FIFO register (the last packet received)

It is recommended that the received packet be released immediately after updating any statistics, to free up buffer memory.

Revision 1.0 (08-14-08)

52

SMSC AN 9.6

APPLICATION NOTE

Contents

1 Overview 1.1Audience 2 Introduction Page 3 Description Of Bus Interface Unit (BIU) 3.2ISA Bus 3.38-BitBus 3.3.1Address Decoding Example 3.3.2I/O Base Address 300h Decoding 3.4Asynchronous Interface 3.4.1Typical Signal Connection with Asynchronous Buses 3.4.2Signal Connection with Asynchronous Interfacing 3.5Synchronous Interface (VL-Bus) 3.5.1Typical Connection with Synchronous Interface (VL-Bus) 3.5.2Signal Connection with Synchronous Interfacing LAN91C111 3.5.3Address Bus 3.5.4AEN 3.5.5W/NR 3.5.6NRDYRTN 3.5.7NSRDY 3.5.8LCLK – Clock Input 3.5.9Reset 3.5.10 NBE0-NBE3 3.6Timing Analysis 3.6.1Write Cycle Address Phase - Cycle Start 3.6.2Write Cycle Data Phase - Cycle End 3.6.3Read Cycle 3.6.4Read Cycle Address Phase – Cycle Start 3.6.5Read Cycle Delay Phase 3.6.6Read Cycle Data Phase – Cycle End 3.7Direct Data Register Access interface (nDATACS) 3.7.1The Use of NDATACS 3.7.2Pointer Register 3.7.3Data Register 3.7.4Timing Analysis Of Direct Access 3.8Asynchronous Read or Write Operation – Non Burst 3.9Burst Mode Operation Timing – Synchronous Operation 3.10 Burst Mode Write Operation 3.11 Burst Mode Read Operation 3.12 LAN91C111 Bus Interface 3.13 Sample Routine of Performance Measurement and Tuning Flow Chart 4 System Hardware Design 4.1Quartz Crystal 4.2Clock Oscillator 4.3X25OUT 4.4Serial EEPROM Operation 4.4.1INDIVIDUAL ADDRESS 20-22hex 4.4.2Use the Serial EEPROM as an Option 4.4.3How to Change the IOBASE Address 4.5Power Supply Decoupling 4.6System Power Consumption 4.7Auto Negotiation 4.7.1Initialization Sequence Steps Page 4.9Loopback 4.9.1EPH Internal Loopback (MAC) 4.9.2Diagnostic Loopback 4.9.3External Loopback Page 4.10 LED Operation 4.10.1LED Description 4.11 Thermal Information 5 Memory Management Unit - Features and Benefits 5.1Memory Partitioning 6 Big and Little Endian Issues on the LAN91C111 6.1Introduction 6.2Definition 6.2.1Big Endian 6.2.2Little Endian 6.3Implications for the LAN91C111 6.4Physical connections for Big Endian Page 6.5Software Considerations for Big Endian 6.6Source Code Example Page 6.6.1Conclusion 7 Physical Layer and Magnetics 7.1Transmit / Receive Interface 7.1.1Transmit Interface 7.1.2Receive Interface 7.1.3Magnetics 7.2RBIAS 7.2.1RBIAS pin 7.2.2TP Transmit Output Current Set 7.2.3Cable Selection 7.2.4Transmitter Droop 7.3MII Management Functions 7.3.1Example Routines To Read and Write the PHY Registers Page Page Page 7.4Multiple Register Access 8 Reset Operation 9 Functional Test and Diagnostic 9.1MAC Register Test 9.2RAM Buffer Test 9.3Transmitting A Packet 9.4Releasing The Transmitted Packet 9.5Receiving A Packet 9.6Releasing A Received Packet 9.7EPH Loopback Test 9.8PHY Loopback Test 9.9External Loopback Test 9.10 MMU Test Page 10 Migrating From LAN91C100FD and LAN83C183 to LAN91C111 10.1 91C111 Overview 10.2 New Features and Modification 10.2.1 Receive/PHY Control Register 10.2.2Memory Information Register 10.2.3 RX_OVRN bit 10.2.4 MDINT Interrupt bit 10.2.5Internal PHY Registers 10.2.6Media Independent Interface (MII) 10.2.7 Power Management 10.2.8Internal PHY and External PHY Selection 10.2.9 General Purpose Output 10.2.10 Reset 10.2.11 Interrupt Pin (INTR0) 10.2.12 SRAM Interface 10.2.13X25OUT Clock Output Pin 11 Design and Layout Check Guidelines