may 16, 20001. 2 usb 2.0 hub additions john garney hub working group chair intel corporation john...

May 16, 2000 1

May 16, 2000 2

USB 2.0 Hub Additions

USB 2.0 Hub Additions

John GarneyJohn GarneyHub Working Group ChairHub Working Group Chair

Intel CorporationIntel Corporation

John GarneyJohn GarneyHub Working Group ChairHub Working Group Chair

Intel CorporationIntel Corporation

May 16, 2000 3

Hub AdditionsHub Additions

Requirements and ArchitectureRequirements and Architecture– Additions to USB1.1Additions to USB1.1

Transaction TranslatorTransaction Translator Bulk/Control Transaction HandlingBulk/Control Transaction Handling Isochronous/Interrupt Transaction HandlingIsochronous/Interrupt Transaction Handling

Additions to Chapter 11Additions to Chapter 11

May 16, 2000 4

Requirements:Requirements:

Provide high-speed expansionProvide high-speed expansion Isolate full/low-speed from high-speedIsolate full/low-speed from high-speed

– Avoid lower speed impact on HS, i.e., LS impact on FSAvoid lower speed impact on HS, i.e., LS impact on FS

All USB2.0 Hub Ports support HS/FS/LSAll USB2.0 Hub Ports support HS/FS/LS

Optional: standardized port indicators (LEDs)Optional: standardized port indicators (LEDs)

May 16, 2000 5

System SWSystem SW

Client DriverClient Driver Client DriverClient Driver

USB 1.1 USB 1.1 DeviceDevice


HS HubHS HubHS HubHS Hub

USB 1.1 HubUSB 1.1 Hub



HS DeviceHS DeviceHS DeviceHS Device

USB 2.0 HostUSB 2.0 HostControllerController

USB 2.0 HostUSB 2.0 HostControllerController

Full/Low SpeedFull/Low Speed

High Speed OnlyHigh Speed Only

(2 x 12Mb/s(2 x 12Mb/sCapacity)Capacity)

Hub In High Speed SystemHub In High Speed System

Hub provides high-speed expansion (ala 1.1 hub)Hub provides high-speed expansion (ala 1.1 hub) Hub provides additional classic bus(es)Hub provides additional classic bus(es)

– Same total number of devices per USB2.0 Host Controller (e.g. 127)Same total number of devices per USB2.0 Host Controller (e.g. 127) Greater end user value than classic hubGreater end user value than classic hub

– Performance, expansion and ease of usePerformance, expansion and ease of use Hub is user selected device (not required for all systems)Hub is user selected device (not required for all systems)

May 16, 2000 6

Reuse Classic Hub

Reuse Classic Hub

Design Knowledge

Design KnowledgeReuse Classic Hub

Reuse Classic Hub

Design Knowledge

Design Knowledge

HS/Classic HS/Classic Hub StateHub StateMachineMachine


HS/Classic HS/Classic HubHub

RepeaterRepeater


RepeaterRepeater


ControllerController




PortPort PortPort PortPort

PortPort

Hub “Classic Pieces”Hub “Classic Pieces”

RepeaterRepeater– High speed signalingHigh speed signaling

Also, FS/LS signaling for 1.1 compatibilityAlso, FS/LS signaling for 1.1 compatibility– ReclockingReclocking

State MachineState Machine– HS termination sequencingHS termination sequencing

HS Detect, Reset, Suspend, ResumeHS Detect, Reset, Suspend, Resume Hub ControllerHub Controller

– Respond to hub device class requests/eventsRespond to hub device class requests/events

May 16, 2000 7

Hub ArchitectureHub Architecture

Same as classic hub:Same as classic hub:– High & full/low-speed repeaters, determined by upstream facing linkHigh & full/low-speed repeaters, determined by upstream facing link– Hub controllerHub controller– No different then classic USB besides high-speed signalingNo different then classic USB besides high-speed signaling

Minor changes from classic hub:Minor changes from classic hub:– Hub state machine (HS detect, HS termination transitions, test mode)Hub state machine (HS detect, HS termination transitions, test mode)

New in hub:New in hub:– Transaction TranslatorTransaction Translator– Routing logicRouting logic





TransactionTransactionTranslatorTranslator


Full/LowFull/LowSpeedSpeed


. . . . .. . . . .



Routing LogicRouting Logic


PortPort


RepeaterRepeater


RepeaterRepeater

May 16, 2000 8

Routing LogicRouting Logic Routing LogicRouting Logic


TransactionTransactionTranslatorTranslatorFull/LowFull/Low

SpeedSpeed

High Speed OnlyHigh Speed OnlyPortPort

Repeater, Controller, ...Repeater, Controller, ...Repeater, Controller, ...Repeater, Controller, ...


Hub New PiecesHub New Pieces

Port Routing LogicPort Routing Logic– Controllable electrical connection between:Controllable electrical connection between:

Full/Low (Transaction Translator), orFull/Low (Transaction Translator), or High-Speed (Repeater)High-Speed (Repeater)

– Route done once per device resetRoute done once per device reset Transaction TranslatorTransaction Translator

– Major addition for USB 2.0Major addition for USB 2.0– Uses split transaction protocol HC supportUses split transaction protocol HC support

. . . . .. . . . .

May 16, 2000 9

Host Controller / TT InteractionsHost Controller / TT Interactions

HostHostHostHost

DeviceDeviceDeviceDevice

TTTTTTTTXX22

TT buffers full/low speed transaction information (X) locallyTT buffers full/low speed transaction information (X) locally

1 – SPLIT-s, OUT, DATAx1 – SPLIT-s, OUT, DATAx(Start-split)(Start-split)

Host Controller issues start-split transaction to TTHost Controller issues start-split transaction to TT

TTTTTTTT RR

4 - ...,ACK4 - ...,ACK

TT buffers full/low speed transaction results (R) locallyTT buffers full/low speed transaction results (R) locally

3 - OUT, DATAx, ...3 - OUT, DATAx, ...

TT issues full/low speed transaction on downstream busTT issues full/low speed transaction on downstream bus

6 - …,ACK6 - …,ACK

TT responds with resultsTT responds with results

InterruptInterruptOutOut

ExampleExample

5 – SPLIT-c, OUT, …5 – SPLIT-c, OUT, …(Complete-split)(Complete-split)

Host Controller issues complete-split transaction to TTHost Controller issues complete-split transaction to TT

May 16, 2000 10

Transaction Translator Overview Transaction Translator Overview

Two separate portions to Transaction TranslatorTwo separate portions to Transaction Translator– Bulk/Control supportBulk/Control support– Interrupt/Isochronous supportInterrupt/Isochronous support

Bulk/Control uses USB flow control to make progressBulk/Control uses USB flow control to make progress– PING not usedPING not used

Interrupt/Isochronous uses a scheduled full/low speed transaction “pipeline”Interrupt/Isochronous uses a scheduled full/low speed transaction “pipeline” Separate buffers are used for each TT portionSeparate buffers are used for each TT portion

Transaction TranslatorTransaction TranslatorTransaction TranslatorTransaction Translator

Bulk &ControlBulk &Control

Interrupt &IsochronousInterrupt &

Isochronous

May 16, 2000 11

TT Bulk / ControlTT Bulk / Control

TT buffers 2 or more bulk/control transactionsTT buffers 2 or more bulk/control transactions TT issues full/low speed transaction when no periodicTT issues full/low speed transaction when no periodic

transactions pendingtransactions pending Host controller issues split transactions to TTHost controller issues split transactions to TT

– Allows starting/completing full/low-speed transactions each microframeAllows starting/completing full/low-speed transactions each microframe– Normal approach of “bandwidth reclamation” is usedNormal approach of “bandwidth reclamation” is used– Tries to issue HS start-split; if successful, next attempt does complete-splitTries to issue HS start-split; if successful, next attempt does complete-split

TTTTTTTT

Bulk/Ctrl #1Bulk/Ctrl #1 Bulk/Ctrl #2Bulk/Ctrl #2

High Speed Start-/Complete-SplitHigh Speed Start-/Complete-Split

Full/Low Speed TransactionFull/Low Speed Transaction

May 16, 2000 12

TT Int. / Isoch. PipelineTT Int. / Isoch. Pipeline

Host software budgets when full/low-speed transaction will runHost software budgets when full/low-speed transaction will run Host schedules start-split before “earliest” start timeHost schedules start-split before “earliest” start time Host schedules complete-split at “latest” finish timesHost schedules complete-split at “latest” finish times Scheduling accounts for variation due to bit-stuffingScheduling accounts for variation due to bit-stuffing

and timeouts, etc.and timeouts, etc.

TTTTTTTT

High Speed Start-SplitHigh Speed Start-Split High Speed Complete-SplitHigh Speed Complete-Split

Start-splitStart-splitFIFOFIFO


Complete-splitComplete-splitFIFOFIFO


StartStartHandlerHandler


CompleteCompleteHandlerHandler


Full/LowFull/LowHandlerHandlerFull/LowFull/LowHandlerHandler

May 16, 2000 13

TTTTTTTT





Full/LowFull/LowHandlerHandlerFull/LowFull/LowHandlerHandler





XX22

TT buffers full/low speed transaction information locally

1 – SPLIT-s, OUT, DATAx1 – SPLIT-s, OUT, DATAx

Host Controller issues start-split transaction to TT

3 - OUT, DATAx, ...3 - OUT, DATAx, ...

TT issues full/low speed transaction on downstream bus

5 – SPLIT-c, OUT, ...5 – SPLIT-c, OUT, ...

Host Controller issues complete-split transaction to TT

6 - …,ACK6 - …,ACK

TT responds with results

Example: Int. OUT Split Trans.Example: Int. OUT Split Trans.

RR

4 - ...,ACK4 - ...,ACK

TT buffers full/low speed transaction results locally



May 16, 2000 14

Hub Cost / Complexity EstimateHub Cost / Complexity Estimate

Classic Hub + new thingsClassic Hub + new things– Classic Hub - implementation dependent, but knowable baselineClassic Hub - implementation dependent, but knowable baseline– New thingsNew things

SignalingSignaling Required for any High-Speed deviceRequired for any High-Speed device

Logic (routing, TT)Logic (routing, TT) RAM (buffer space, transaction pipeline)RAM (buffer space, transaction pipeline)

Total (approximate)Total (approximate)– 40KGates + 1800 Bytes with 4 downstream ports40KGates + 1800 Bytes with 4 downstream ports– 28KGates + (3KG * # of downstream ports) + 1800 Bytes28KGates + (3KG * # of downstream ports) + 1800 Bytes

TT FIFOsTT FIFOsTT FIFOsTT FIFOs

TT LogicTT LogicTT LogicTT Logic

Port

High-Speed “Classic Hub”High-Speed “Classic Hub”High-Speed “Classic Hub”High-Speed “Classic Hub”

Port Port Port

Routing LogicRouting Logic

May 16, 2000 15

USB2.0 HubAdditions SummaryUSB2.0 HubAdditions Summary

Hub Ports Support all Speeds (High/Full/Low)Hub Ports Support all Speeds (High/Full/Low)– Isolation of High and Full/Low Speeds via TTIsolation of High and Full/Low Speeds via TT

Simultaneous High and Full/Low-Speed TransactionsSimultaneous High and Full/Low-Speed Transactions– Full/Low Speed (12Mb/s) bus per TTFull/Low Speed (12Mb/s) bus per TT

Can be TT per hub or TT per portCan be TT per hub or TT per port

TT Internals OverviewTT Internals Overview– Bulk/Control bufferingBulk/Control buffering– Interrupt/Isochronous scheduled pipelineInterrupt/Isochronous scheduled pipeline

may 16, 20001. 2 usb 2.0 hub additions john garney hub working group chair intel corporation john...

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