Texas Instruments TMS380C26 Architecture, Communications processor CP, System interface SIF

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TMS380C26

NETWORK COMMPROCESSOR

SPWS010A±APRIL 1992±REVISED MARCH 1993

architecture

The major blocks of the TMS380C26 include the Communications Processor (CP), System Interface (SIF), Memory Interface (MIF), Protocol Handler (PH), Clock Generator (CG), and the Adapter Support Function (ASF). The functionality of each block is described in the following sections.

communications processor (CP)

The Communications Processor (CP) performs the control and monitoring of the other functional blocks in the TMS380C26. The control and monitoring protocols are specified by the software (downloaded or ROM-based) in local memory. Available protocols include:

•Media Access Control (MAC) software,

•Logical Link Control (LLC) software, (token ring version only), and

•Copy All Frames (CAF) software.

The CP is a proprietary 16-bit central processing unit (CPU) with data cache and a single prefetch pipe for pipelining of instructions. These features enhance the TMS380C26's maximum performance capability to about 4 million instructions per second (MIPS), with an average of about 2.5 MIPS.

system interface (SIF)

The System Interface (SIF) performs the interfacing of the LAN subsystem to the host system. This interface may require additional logic depending on the application. The system interface can transfer information/data using any of these three methods:

•Direct Memory Access (DMA),

•Direct Input/Output (DIO), or

•Pseudo-Direct Memory Access (PDMA).

DMA (or PDMA) is used to transfer all data to/from host memory from/to local memory. DIO's main uses are for loading the software to local memory and for initializing the TMS380C26. DIO also allows command/status interrupts to occur to and from the TMS380C26.

The system interface can be hardware selected for either of two modes by use of the SI/M pin. The mode selected determines the memory organizations and control signals used. These modes are:

•The Intel 80x8x families: 8-, 16-, and 32-bit bus members

•The Motorola 68000 microprocessor family: 16- and 32-bit bus members

The system interface supports host system memory addressing up to 32 bits (32-bit reach into the host system memory). This allows greater flexibility in using/accessing host system memory.

System designers are allowed to customize the system interface to their particular bus by:

•Programmable burst transfers or cycle-steal DMA operations

•Optional parity protection

These features are implemented in hardware to reduce system overhead, facilitate automatic rearbitration of the bus after a burst, or repeat a cycle when errors occur (parity or bus). Bus retries are also supported.

The system interface hardware also includes features to enhance the integrity of the TMS380C26 and the data. These features do the following:

•Always internally maintain odd byte parity regardless if parity is disabled,

•Monitor for the presence of a clock failure.

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Contents Network Commprocessor Attached System Bus LAN SubsystemPinout PIN Quad Flat Pack TOP ViewDescription Block diagram and signal descriptions PIN Name Description TMS380C26Terminal Functions Maxph AX1 AX0Maxpl AX3 AX2Sreset Mreset OUTMOE MrasPrtyen NSELOUT0 NSELOUT1= H SbheSintr Sddir Direction DIO DMAShrq SRD SWR108 Reserved. This signal must be left unconnected see Note = Selects 8-bit mode see Note= Selects 16-bit mode SyncinSBHE/ Srnw System Interface ± Motorola Mode SI/M= L Terminal Functions = L SbgrSbrq SirqSlds SudsSdtack FRAQ/TXD NsrtPxtalin RCVR/RXDColl LpbkTXC Terminal Functions Vssl VSS1 VSS2VSS3 VSS4 VSS5 VSS6System interface SIF ArchitectureCommunications processor CP Memory interface MIF Protocol handler PHAdapter support function ASF Clock generator CGAdapter-Internal Pointers for Token-Ring² Address DescriptionAdapter-Internal Pointers for Ethernet ² User-Access Hardware Registers ³ 68xxx Mode is always 16-bitWord Transfers Byte TransfersBits 0-2 Test 0±2. Value on Test 0±2 pins Bit 5 Swddir Ð Current Sddir Signal ValueSIF Adapter Control Register Sifacl Sifacl RegisterBit 6 Swhrq Ð Current Shrq Signal Value Bit 7 Psdmaen Ð Pseudo-System-DMA EnableBit 8 Areset Ð Adapter Reset Bit 10 Boot Ð Bootstrap CP CodeBit 12 Sinten Ð System-Interrupt Enable Bit 13 PEN Ð Adapter Parity EnableBit 14 Ð 15 Nselout 0±1 Ð Network selection outputs System Psdmaen Swhrq Swhlda Sinten Interrupt ResultSifacl Control for Pseudo-DMA Operation Systeminterrupt SINTR/SIRQDMA SHRQ/SBRQ Dmadir Sddir Swhlda Swddir Swhrq Psdmaen SintenRecommended operating conditions MIN NOM MAX UnitParameter Test Conditions MIN TYP MAX Unit See NoteTest measurement High LowVload IOL Output Under TestClkdiv = Oscout MBCLK1² MBCLK2² Reference PeriodsWhen Static signals Timing parameter symbologySignal Function Timing parameters289² ThRST Hold time of DMA size from High Intel mode only Parameter MIN MAX UnitReaches minimum high level HVDDH-RSL 118² Pulse duration HighVDD Sbclk Oscin MBCLK1 MBCLK2 Sreset S8/SHALT Minimun VDD High Level103 101 106 104 105 102 107 110 108 109 111 117 118 119 288 289126 Delay time from MBCLK1 no longer low to Valid MresetNMI 121 Hold time Valid after MBCLK1 lowMADH0±MADH7 MresetMBCLK1 MBCLK2 MAX0 MAX2 ADD/EN Mromen Maxph Maxpl Mromen MAL Memory bus timing clocks, MRAS, MCAS, and MAL to AddressMADL0±MADL7 Maxph Maxpl Column Row AddressAddress Status Column StatusMemory bus timing read cycle Mcas MOEMaxph Maxpl MADH0±MADH7 Maxph MaxplMAX0 MAX2 Mromen Mras McasAddress Status Data/Parity MbiaenMemory bus timing write cycle Enable Address MAX0, AddressMAX2 Mromen Mras Mcas MbenMemory bus timing TMS380C26 releases control of bus Parameter MINMddir MAL Mbiaen Mbrq Mbgr MBCLK1 MBCLK2 Mben75a 74a Hold time Valid after MBCLK1 low, bus resume Setup time High before MBCLK1 rising edge, bus resumeMemory bus timing TMS380C26 resumes control of bus Memory Bus Timing TMS380C26 Resumes Control of Bus Mben Mddir MAL Mbiaen Mbrq Mbgr Hold time Low after MBCLK2 low, external bus master read Memory bus timing external bus master read from TMS380C26Macs Mddir Macs MBCLK1 MBCLK2MAX0 MAX2 Maxph Maxpl MADH0±MADH7 Data/Pty Memory bus timing external bus master write to TMS380C26MAX0, MAX2 Maxph Maxpl Memory bus timing Dram refresh timing MADL0±MADL7 Mras73a Mcas MrefXmatch and Xfail timing Bit127 128 Xmatch XfailToken ring Ð ring interface timing Parameter MIN TYP MAX UnitRclk RcvrToken ring Ð transmitter timing see Figure Rclk or PxtalinDrvr 160 159Ethernet timing of clock signals Ethernet timing of Xmit signalsTXD TxenEthernet timing of RCV signals Ð start of frame CRSRXC RXDEthernet timing of RCV signals Ð end of frame Crshld320 321 322TXD Txen Ethernet timing of RCV signals Ð no RXCNorxc 350 TXC TXDData JAM80x8x DIO read timing SCS, Srsx SRS0± SRS2 SbheSras Sdben80x8x DIO write timing Valid 264 265 268 256 267 272a 280 281281a 282W 283W 276 279 275 282b80x8x interrupt acknowledge timing ± first Siack pulse 80x8x interrupt acknowledge timing ± second Siack pulseSRD, SWR SCS Siack 287 First 286 SecondSCS, Srsx SRS0±SRS2 Sbhe Siack SWR SRD Sddir HighSdben SRDY²HI-Z SADH0±SADH7 SADL0±SADL7,HI-ZSPH, SPL80x8x mode bus arbitration timing, SIF takes control SownSRD SWR SWR SownSADL0±SADL7 SPH, SPL Sbbsy ShldaSRD, SWR After Sbclk low to guarantee recognition on this cycle 212 Delay from Sbclk low to address valid 214 ²This cycle 208b High TwSCKL ±Sbclk Sras 80x8x mode DMA write timing SldsSRD High SADL0±SADH7SADH0±SADL7 SPH, SPL Sddir High80x8x mode bus arbitration timing, SIF returns control 80x8x mode bus release timing Sbrls SownTW or 208c68xxx DIO read timing SRS0, SRS1 Siack SrnwSuds Slds SDTACK²HI-Z SADH0±SADH7 SADL0±SADL7,HI-Z SPH, SPL68xxx DIO write timing Suds Slds SdtackSCS SRSX, SRS0, SRS1 Siack Srnw SDBEN³SDTACK² SADH0±SADH7 SADL0±SADL7,HI-Z SPH, SPL68xxx interrupt acknowledge cycle timing SCS SiackSCS Srnw Sdtack Siack SdtackSCS, Srsx SRS0, SRS1 Sbhe Siack Srnw Slds Sdben SDTACK² HI-ZSADH0±SADH7 SADL0±SADL7, HI-ZSPH, SPL 275 282a 25568xxx mode bus arbitration timing, SIF takes control 241 Delay from Sbclk high in TX cycle to HighSbgr SbrqSberr Sdtack Sbbsy SAS, SldsSuds Srnw SADH0±SADH7 HI-Z SADL0±SADL7 SPH, SPL68xxx mode DMA read timing 237R Delay from Sbclk high in the T2 cycle to LowOn this cycle 208b Suds SASSale SADL0±SADH7 SADH0±SADL7 SPH, SPL 68xxx mode DMA write timing Sdben Suds SldsSAS SADL0±SADH7, SADH0±SADL7 SPL, SPH68xxx mode bus arbitration timing, SIF returns control 240 ² Setup SRNW,Sbclk Sbgr Sdtack Read HI-Z WriteSIF HI-Z Write Read68xxx mode bus release and error timing Sown SberrSbrls Sown Sberr SdtackRerun cycle with delayed start² Normal completion with delayed start²Sbclk Sdtack Sberr Shalt TH B TH E Sbclk Sdtack Sberr Shalt SownJedec plastic leaded quad flat package PQ suffix 254 0.010 NOM 635 0.025 NOM 76 0.030 NOMJedec NO. Outline Terminals MIN MAX MO±069±ADImportant Notice
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