May 9, 20012 USB On-The-Go Kosta Koeman Cypress Semiconductor Kosta Koeman Cypress Semiconductor.

May 9, 2001 2

USB On-The-GoUSB On-The-Go

Kosta KoemanCypress Semiconductor

Kosta KoemanCypress Semiconductor

May 9, 2001 3

AgendaAgenda

History Contributors Why USB On-The-Go? Applications Goal of the specification Cables & Connectors On-The-Go spec details Summary

History Contributors Why USB On-The-Go? Applications Goal of the specification Cables & Connectors On-The-Go spec details Summary

May 9, 2001 4

HistoryHistory

USB On-The-Go started in June, 1999 To date, over 2 dozen companies have

contributed to the OTG specification Original intent was to connect portables directly

together for specific applications

USB On-The-Go started in June, 1999 To date, over 2 dozen companies have

contributed to the OTG specification Original intent was to connect portables directly

together for specific applications

May 9, 2001 5

ContributorsContributors

Advanced-Connectek, Inc. Aten Cypress Semiconductor Ericsson Hewlett-Packard Company Imation InSilicon Corporation Intel Corporation Lumburg Maxim Integrated Products MCCI Microsoft Molex

Advanced-Connectek, Inc. Aten Cypress Semiconductor Ericsson Hewlett-Packard Company Imation InSilicon Corporation Intel Corporation Lumburg Maxim Integrated Products MCCI Microsoft Molex

Motorola NEC Systems, Inc Nokia OnSpec Opti, Inc. Palm, Inc. Philips Qualcomm ScanLogic Texas Instruments, Inc TransDimension, Inc. Tyco Electronics V-Automation

Motorola NEC Systems, Inc Nokia OnSpec Opti, Inc. Palm, Inc. Philips Qualcomm ScanLogic Texas Instruments, Inc TransDimension, Inc. Tyco Electronics V-Automation

May 9, 2001 6

Why USB On-The-Go?Why USB On-The-Go?

USB provides a very inexpensive infrastructure for connecting slave peripherals to a host PC

OTG extends the architecture to allow USB peripherals to have host capability

This resulted in a very cost effective meansof providing point-to-point communication between peripherals

New means for generating content are introduced

USB provides a very inexpensive infrastructure for connecting slave peripherals to a host PC

OTG extends the architecture to allow USB peripherals to have host capability

This resulted in a very cost effective meansof providing point-to-point communication between peripherals

New means for generating content are introduced

May 9, 2001 7

ApplicationsApplications

MasterMaster SlaveSlave ApplicationApplication

Mobile PhoneMobile Phone Mobile PhoneStill Image Camera MP3 Player Mass StorageScannerPDA

Mobile PhoneStill Image Camera MP3 Player Mass StorageScannerPDA

Exchange contact informationEmail pictures, upload pictures to webUpload/download/broadcast musicUpload/download filesScan business cardsExchange contact information

Exchange contact informationEmail pictures, upload pictures to webUpload/download/broadcast musicUpload/download filesScan business cardsExchange contact information

Still Image CameraStill Image Camera Still Image CameraMobile PhonePrinterMass Storage

Still Image CameraMobile PhonePrinterMass Storage

Exchange picturesEmail pictures, upload pictures to webPrint picturesStore pictures

Exchange picturesEmail pictures, upload pictures to webPrint picturesStore pictures

PrinterPrinter Still Image Camera ScannerMass Storage

Still Image Camera ScannerMass Storage

Print picturesPrint scanned imagePrint files stored on device

Print picturesPrint scanned imagePrint files stored on device

MP3 PlayerMP3 Player MP3 Player Mass Storage MP3 Player Mass Storage

Exchange songsUpload/download songs Exchange songsUpload/download songs

May 9, 2001 8

More ApplicationsMore Applications

MasterMaster SlaveSlave ApplicationApplication

OscilliscopeOscilliscope PrinterPrinter Print screen imagePrint screen image

PDAPDA PDAPrinterMobile PhoneMP3 Player ScannerMass StorageGPSStill Image CameraOscilliscopeKeyboard

PDAPrinterMobile PhoneMP3 Player ScannerMass StorageGPSStill Image CameraOscilliscopeKeyboard

Exchange filesPrint filesUpload/download files Upload/download songsScan picturesUpload/download files Obtain directions, mapping informationUpload picturesConfigure oscilliscope

Exchange filesPrint filesUpload/download files Upload/download songsScan picturesUpload/download files Obtain directions, mapping informationUpload picturesConfigure oscilliscope

May 9, 2001 9

Goal of On-The-GoGoal of On-The-Go

Connect 2 USB devices directly Communicate in a “USB manner”

– Utilize USB’s master/slave architecture Master first resets and configures the slave

More geared towards portable devices– New connectors

Standard connectors are too big

– Small amount of current (4 ma) Typically battery-powered devices OTG device may supply more

– Non-portables can be OTG too May even supply 500 ma!

Connect 2 USB devices directly Communicate in a “USB manner”

– Utilize USB’s master/slave architecture Master first resets and configures the slave

More geared towards portable devices– New connectors

Standard connectors are too big

– Small amount of current (4 ma) Typically battery-powered devices OTG device may supply more

– Non-portables can be OTG too May even supply 500 ma!

May 9, 2001 10

Goal of On-The-GoGoal of On-The-Go

Minimize deviations from the USB spec– Session start protocols– Use of VBUS and Pull-up resistors for “signaling”– Limited host capability

Transfer types Limited number of devices supported

– 4 ma <= Current supplied <= 500 ma Provide good user experience

– inform user if remote device is not supported

Minimize deviations from the USB spec– Session start protocols– Use of VBUS and Pull-up resistors for “signaling”– Limited host capability

Transfer types Limited number of devices supported

– 4 ma <= Current supplied <= 500 ma Provide good user experience

– inform user if remote device is not supported

May 9, 2001 11

Cables & ConnectorsCables & Connectors

Connectors

New Cables

Adapters

Usability Study

Connectors

New Cables

Adapters

Usability Study

May 9, 2001 12

ConnectorsConnectors

Already defined in USB 2.0 specification– New ID pin (not connected & no corresponding wire)– Mini-B plug– Mini-B receptacle

On slave-only devices

Introduced by On-The-Go specification– Mini-A plug

ID Pin shorted to GND

– Mini-A receptacle (only allowed on adapters)– Mini-AB receptacle

Accepts both mini-A & mini-B plugs On dual-role devices

Already defined in USB 2.0 specification– New ID pin (not connected & no corresponding wire)– Mini-B plug– Mini-B receptacle

On slave-only devices

Introduced by On-The-Go specification– Mini-A plug

ID Pin shorted to GND

– Mini-A receptacle (only allowed on adapters)– Mini-AB receptacle

Accepts both mini-A & mini-B plugs On dual-role devices

May 9, 2001 13

ConnectorsConnectors

2 Connector Types– Indicate the default roles– Different by

Overmold Keying Colors inside plug

– ID pin Shorted to GND on mini-A plug Disconnected on mini-B plug

2 Connector Types– Indicate the default roles– Different by

Overmold Keying Colors inside plug

– ID pin Shorted to GND on mini-A plug Disconnected on mini-B plug

May 9, 2001 14

CablesCables

Already defined– Standard-A to Standard-B (26ns ‘long’)– Standard-A to Mini-B (26ns ‘long’)

New– Mini-A to Mini-B (*25ns ‘long’)– Mini-A to Standard-B (*25ns ‘long’)

Already defined– Standard-A to Standard-B (26ns ‘long’)– Standard-A to Mini-B (26ns ‘long’)

New– Mini-A to Mini-B (*25ns ‘long’)– Mini-A to Standard-B (*25ns ‘long’)

*Note: ‘Shorter’ cable allows for adapter*Note: ‘Shorter’ cable allows for adapter

May 9, 2001 15

AdaptersAdapters

Mini-A plug to standard-A plug– Has mini-A receptacle, standard-A plug– Connect OTG devices with tethered mini-A plugs

(such as mice) to standard ports

* Mini-A receptacles exist nowhere else!

Mini-A plug to standard-A plug– Has mini-A receptacle, standard-A plug– Connect OTG devices with tethered mini-A plugs

(such as mice) to standard ports

* Mini-A receptacles exist nowhere else!

Mini-A plugMini-A plug

Mini-A receptacle*Mini-A receptacle* Standard-A PlugStandard-A Plug

Standard-A receptacleStandard-A receptacle

USB Port (Hub Or Root Port)USB Port (Hub Or Root Port)

OTG SlaveOTG Slave

May 9, 2001 16

AdaptersAdapters

Standard-A plug to Mini-A plug– Has standard-A receptacle, a mini-A plug– Connect USB devices with tethered standard-A plugs

to OTG devices

Standard-A plug to Mini-A plug– Has standard-A receptacle, a mini-A plug– Connect USB devices with tethered standard-A plugs

to OTG devices

Standard-A plugStandard-A plug

Standard-A receptacleStandard-A receptacleMini-A PlugMini-A Plug

Mini-AB receptacleMini-AB receptacle

OTG DeviceOTG DeviceUSB DeviceUSB Device

May 9, 2001 17

AdaptersAdapters

Adapters using mini-B plug or receptacleare prohibited– Examples of prohibited adapters

Mini-B receptacle to Standard-B plug Standard-B receptacle to Mini-B plug

Must guarantee that an adapter is used onlyon one end of the cable– Maximum propagation delay of cable/adapter

combination is not exceeded– Signal quality is not compromised– Voltage drops are within specification

Adapters using mini-B plug or receptacleare prohibited– Examples of prohibited adapters

Mini-B receptacle to Standard-B plug Standard-B receptacle to Mini-B plug

Must guarantee that an adapter is used onlyon one end of the cable– Maximum propagation delay of cable/adapter

combination is not exceeded– Signal quality is not compromised– Voltage drops are within specification

May 9, 2001 18

TimingsTimings

Must preserve 30 ns delay from TP1 to TP4 to allow for high-speed signaling

Must preserve 30 ns delay from TP1 to TP4 to allow for high-speed signaling

USB Cable

Device Circuit BoardDevice Circuit Board Hub Circuit BoardHub Circuit Board

AConnector

AConnector

TracesTraces TracesTraces

TransceiverTransceiver TransceiverTransceiver

TP4TP4 TP3TP3 TP2TP2 TP1TP1

BConnector

BConnector

May 9, 2001 19

TimingsTimings

Scenario 1Scenario 1 TimeTime Scenario 2Scenario 2 TimeTime

Standard Host

Mini-A receptacle toStandard-A plug

Mini-A to Mini-Bcable

OTG device

Total

Standard Host

Mini-A receptacle toStandard-A plug

Mini-A to Mini-Bcable

OTG device

Total

3 ns

1 ns

25 ns

1 ns

30 ns

3 ns

1 ns

25 ns

1 ns

30 ns

OTG Host

Standard-A receptacleto Mini-A plug

Standard-A toStandard-B cable

USB peripheral

Total

OTG Host

Standard-A receptacleto Mini-A plug

Standard-A toStandard-B cable

USB peripheral

Total

1 ns

1 ns

26 ns

1 ns

29 ns

1 ns

1 ns

26 ns

1 ns

29 ns

May 9, 2001 20

Usability StudyUsability Study

Mini-A & mini-B plugslook similar– Have different “key”– Differentiating via the overmold

Oval for mini-A plug Square for mini-B plug

– Differentiating via color coding inside plugs/receptacles Mini-A - white Mini-B - black Mini-AB - gray

Mini-A & mini-B plugslook similar– Have different “key”– Differentiating via the overmold

Oval for mini-A plug Square for mini-B plug

– Differentiating via color coding inside plugs/receptacles Mini-A - white Mini-B - black Mini-AB - gray

May 9, 2001 21

Usability StudyUsability Study

Solve the potential connectivity problemof connecting a dual-role device to aslave-only device– Insert mini-B plug first into dual-role– Try to insert mini-A plug into slave– Cable must be turned around

Dual-role to Dual-role– No problem. Cable can be connected either way

Slave to slave– Not possible. Don’t want silent failures!

Solve the potential connectivity problemof connecting a dual-role device to aslave-only device– Insert mini-B plug first into dual-role– Try to insert mini-A plug into slave– Cable must be turned around

Dual-role to Dual-role– No problem. Cable can be connected either way

Slave to slave– Not possible. Don’t want silent failures!

May 9, 2001 22

Specification DetailsSpecification Details

Dual-role vs. Slave only Host Capabilities Point-to-Point Communication Master Negotiation Protocol (MNP)

Dual-role vs. Slave only Host Capabilities Point-to-Point Communication Master Negotiation Protocol (MNP)

May 9, 2001 23

Dual Role Vs. Slave OnlyDual Role Vs. Slave Only

Dual Role Mini-AB Receptacle MNP capable Has MNP descriptor* Master: source 4 ma+ Slave: consume 150 ua Some host capability

Dual Role Mini-AB Receptacle MNP capable Has MNP descriptor* Master: source 4 ma+ Slave: consume 150 ua Some host capability

Slave-Only Mini-B receptacle OR

tethered mini-A plug No MNP descriptor* Consume <= 4ma**

Slave-Only Mini-B receptacle OR

tethered mini-A plug No MNP descriptor* Consume <= 4ma**

** Many self-powered USB devices qualify as OTG slaves(self-powered USB devices may consume up to 100 ma)

* MNP descriptor consists of length and type

May 9, 2001 24

Host Capability ComparisonHost Capability Comparison

Support devices for which it has drivers

Support devices for which it has drivers

Standard PC’s/NotebooksStandard PC’s/Notebooks

May have a mechanism for loading more drivers

May have a mechanism for loading more drivers

Limited storage area for drivers

Limited storage area for drivers

Has a mechanism for loading more drivers

Has a mechanism for loading more drivers

“Unlimited” storage area for drivers

“Unlimited” storage area for drivers

OTG DevicesOTG Devices

Supports devices for which it has drivers

Supports devices for which it has drivers

May support all transfer types and speeds

May support all transfer types and speeds

Supports all transfer types and device speeds

Supports all transfer types and device speeds

Must source 4 ma minimum on VBUS

Must source 4 ma minimum on VBUS

Sources either 100 or500 ma on VBUS

Sources either 100 or500 ma on VBUS

1.0µF < C < 6.5µF 1.0µF < C < 6.5µF C > 96µF C > 96µF

May 9, 2001 25

Point-to-Point Point-to-Point

Have point-to-point communication, not peer-to-peer

We have 2 unequal devices connected– A-Device– B-Device– Different initial roles defined by plugs

Have point-to-point communication, not peer-to-peer

We have 2 unequal devices connected– A-Device– B-Device– Different initial roles defined by plugs

May 9, 2001 26

Device TypesDevice Types

A-Devices– Mini-A plug inserted (ID pin shorted)– Supplies power on VBUS – Default master– Must source at least 4 ma (can be more)

B-Device– Mini-B plug inserted (ID pin floating)– Default slave– May consume up to 150 ua

A-Devices– Mini-A plug inserted (ID pin shorted)– Supplies power on VBUS – Default master– Must source at least 4 ma (can be more)

B-Device– Mini-B plug inserted (ID pin floating)– Default slave– May consume up to 150 ua

May 9, 2001 27

MNP OverviewMNP Overview

Master Negotiation Protocol is the mechanism in which an A-device and a B-device exchange the master & slave roles– Virtual reversal of the cable

Pull-up resistor used to signal slave role Again, default roles defined by plugs

Master Negotiation Protocol is the mechanism in which an A-device and a B-device exchange the master & slave roles– Virtual reversal of the cable

Pull-up resistor used to signal slave role Again, default roles defined by plugs

May 9, 2001 28

MNP OverviewMNP Overview

A-device sets “MNP Enable” feature on B-device B-device deasserts pull-up A-device asserts its pull-up resistor

– Indicates that the A-device has submittedto be the slave

A-device still powers VBUS B-device detects A-device’s pull-up

– Resets/enumerates/uses A-device

A-device sets “MNP Enable” feature on B-device B-device deasserts pull-up A-device asserts its pull-up resistor

– Indicates that the A-device has submittedto be the slave

A-device still powers VBUS B-device detects A-device’s pull-up

– Resets/enumerates/uses A-device

May 9, 2001 29

MNP SessionsMNP Sessions

A period in which devices exchange data Two kinds of sessions

– Insertion-based VBUS always on Traditional USB

– Usage-based VBUS on when devices exchange data Allows for power savings Session start protocols

A period in which devices exchange data Two kinds of sessions

– Insertion-based VBUS always on Traditional USB

– Usage-based VBUS on when devices exchange data Allows for power savings Session start protocols

May 9, 2001 30

Session Start ProtocolsSession Start Protocols

B-device – First, pulses its pull-up resistor (Data-line pulsing)– Second, pumps a charge onto VBUS (VBUS pulsing)

Above 2.1 Volts on OTG devices Less than 2.0 Volts on standard hosts

A-device must respond to one method– Can use a comparator or TTL input for detection of

VBUS pulsing– Since it did not start the session, it can quickly give

the B-device permission to assume bus mastership

B-device – First, pulses its pull-up resistor (Data-line pulsing)– Second, pumps a charge onto VBUS (VBUS pulsing)

Above 2.1 Volts on OTG devices Less than 2.0 Volts on standard hosts

A-device must respond to one method– Can use a comparator or TTL input for detection of

VBUS pulsing– Since it did not start the session, it can quickly give

the B-device permission to assume bus mastership

May 9, 2001 31

MNP Example 1MNP Example 1

First Example– Usage-Based A-device– A-device initiates session– A-device supports B-device– B-device supports A-device

First Example– Usage-Based A-device– A-device initiates session– A-device supports B-device– B-device supports A-device

May 9, 2001 32

1. Initial conditions: devices connected, VBUS is powered off, mini-Aplug inserted in A-device, mini-B plug inserted in B-device

1. Initial conditions: devices connected, VBUS is powered off, mini-Aplug inserted in A-device, mini-B plug inserted in B-device


2. User causes A-device to start a session, turns on VBUS. TheB-device detects voltage on VBUS and applies pullup

2. User causes A-device to start a session, turns on VBUS. TheB-device detects voltage on VBUS and applies pullup

A-device B-deviceD+D+

VV BUSBUS = 0V = 0V

GNDGND

D-D-

B-deviceS

B-deviceS

A-deviceM

A-deviceM

D+D+

VV BUSBUS = 5V = 5V

GNDGND

D-D-

3.3 V 3.3 V

May 9, 2001 33


CommandsCommands

4. When A-device is done with B-device, it grants the B-devicepermission to assume bus mastership via set “MNP” command


DataDataB-device

SB-device

S

3. A-device resets B-device, enumerates (get descriptors, setconfiguration, etc.) B-device


A-deviceM

A-deviceM

Set “MNP”Set “MNP”

A-deviceM

A-deviceM

B-deviceS

B-deviceS

May 9, 2001 34


5. B-device signals it wants to assume bus mastership bydeasserting its pull-up


6. A-device sees pull-up is deasserted and asserts its pullup since theB-device has been granted permission to assume bus mastership


B-device

A-deviceS

A-deviceS

A-deviceM

A-deviceM

D+D+

VV BUSBUS = 5V = 5V

GNDGND

D-D-

D+D+

VV BUSBUS = 5V = 5V

GNDGND

D-D- B-device

3.3 V 3.3 V

May 9, 2001 35

B-deviceM

B-deviceM

A-deviceS

A-deviceS

MNP Example 1 MNP Example 1

8. B-device transmits data to/from A-device8. B-device transmits data to/from A-device

7. B-device, seeing the A-device has asserted its pullup, assumesmastership, resets, enumerates the A-device

7. B-device, seeing the A-device has asserted its pullup, assumesmastership, resets, enumerates the A-device

D+D+

VV BUSBUS = 5V = 5V

GNDGNDD-D-

CommandsCommands

DataDataA-device

SA-device

SB-device

MB-device

M

3.3 V 3.3 V

May 9, 2001 36


10. A-device times out from not seeing bus activity, ends session,stops driving VBUS

10. A-device times out from not seeing bus activity, ends session,stops driving VBUS

9. B-device finishes and goes back to being a slave (stopsgenerating bus activity and asserts its pullup). Both devices haveasserted their pull-up resistors.


D+D+

VV BUSBUS = 5V = 5V

GNDGNDD-D-

D+D+

VV BUSBUS = 0V = 0V

GNDGNDD-D- B-deviceA-device

A-deviceS

A-deviceS

A-deviceS

A-deviceS

3.3 V 3.3 V 3.3 V 3.3 V

May 9, 2001 37


Second Example– Usage-based A-device– Session requested by B-device– A-device supports B-device– B-device supports A-device

Second Example– Usage-based A-device– Session requested by B-device– A-device supports B-device– B-device supports A-device

May 9, 2001 38

B-device


1. Initial conditions: devices connected, VBUS is powered off, mini-Aplug inserted in A-device, mini-B plug inserted in B-device1. Initial conditions: devices connected, VBUS is powered off, mini-Aplug inserted in A-device, mini-B plug inserted in B-device

2. User causes B-device to request a session. B-device pulsespullup, pumps charge onto VBUS

2. User causes B-device to request a session. B-device pulsespullup, pumps charge onto VBUS

D+D+

VV BUSBUS = 0V = 0V

GNDGND

D-D-

D+D+

VV BUSBUS = 2.1+V = 2.1+V

GNDGND

D-D-A-device

B-deviceA-device

May 9, 2001 39

B-deviceS

B-deviceS

A-deviceM

A-deviceM

A-deviceM

A-deviceM

B-deviceS

B-deviceS


4. A-device knows that B-device requested session. Acquires MNPdescriptor, then issues set MNP feature4. A-device knows that B-device requested session. Acquires MNPdescriptor, then issues set MNP feature

3. A-device detects session request, turns on VBUS. B-devicedetects VBUS and asserts pullup. 3. A-device detects session request, turns on VBUS. B-devicedetects VBUS and asserts pullup.


D+D+

VV BUSBUS = 5V = 5V

GNDGND

D-D-

3.3 V 3.3 V

May 9, 2001 40

B-device

A-deviceS

A-deviceS

A-deviceM

A-deviceM






D+D+

VV BUSBUS = 5V = 5V

GNDGND

D-D-

D+D+

VV BUSBUS = 5V = 5V

GNDGND

D-D-

3.3 V 3.3 V

B-device

May 9, 2001 41



7. B-device, seeing the A-device has asserted its pullup, assumes mastership, resets, enumerates the A-device7. B-device, seeing the A-device has asserted its pullup, assumes mastership, resets, enumerates the A-device

A-deviceS

A-deviceS

A-deviceS

A-deviceS

B-deviceM

B-deviceM

D+D+

VV BUSBUS = 5V = 5V

GNDGNDD-D-

CommandsCommands

DataData

3.3 V 3.3 V

B-deviceM

B-deviceM

May 9, 2001 42


10. A-device times out from not seeing bus activity, ends session, stops driving VBUS

10. A-device times out from not seeing bus activity, ends session, stops driving VBUS



A-deviceS

A-deviceS

A-deviceS

A-deviceS

D+D+

VV BUSBUS = 5V = 5V

GNDGNDD-D-

D+D+

VV BUSBUS = 0V = 0V

GNDGNDD-D- B-deviceA-device

3.3 V 3.3 V 3.3 V 3.3 V

May 9, 2001 43


Third Example– Insertion-based A-device– A-device supports B-device– B-device supports A-device

Third Example– Insertion-based A-device– A-device supports B-device– B-device supports A-device

May 9, 2001 44

B-deviceS

B-deviceS

A-deviceM

A-deviceM


1. Initial conditions, A-device (mini-A plug inserted) always drivesVBUS waits for B-device to be inserted

1. Initial conditions, A-device (mini-A plug inserted) always drivesVBUS waits for B-device to be inserted

D+D+

VV BUSBUS = 5V = 5V

GNDGND

D-D-

D+D+

VV BUSBUS = 5V = 5V

GNDGND

D-D-

2. User inserts mini-B plug into B-device. B-device sees VBUS andaserts pullup

2. User inserts mini-B plug into B-device. B-device sees VBUS andaserts pullup

A-deviceM

A-deviceM

3.3 V 3.3 V

May 9, 2001 45






B-deviceS

B-deviceS

A-deviceM

A-deviceM

A-deviceM

A-deviceM

B-deviceS

B-deviceS


CommandsCommands

DataData

May 9, 2001 46


6. A-Device sees pull-up is deasserted and asserts its pullup since theB-device has been granted permission to assume bus mastership6. A-Device sees pull-up is deasserted and asserts its pullup since theB-device has been granted permission to assume bus mastership



A-deviceM

A-deviceM

A-deviceS

A-deviceS

D+D+

VV BUSBUS = 5V = 5V

GNDGNDD-D-

D+D+

VV BUSBUS = 5V = 5V

GNDGNDD-D- B-device

B-device

3.3 V 3.3 V

May 9, 2001 47



7. B-device, seeing the A-device has asserted its pullup, assumesmastership, resets, enumerates the a_device

7. B-device, seeing the A-device has asserted its pullup, assumesmastership, resets, enumerates the a_device

A-deviceS

A-deviceS

A-deviceS

A-deviceS

B-deviceM

B-deviceM

B-deviceM

B-deviceM

D+D+

VV BUSBUS = 5V = 5V

GNDGNDD-D-

CommandsCommands

DataData

3.3 V 3.3 V

May 9, 2001 48


10. A-device times out from not seeing bus activity, resumesmastership

10. A-device times out from not seeing bus activity, resumesmastership



A-deviceS

A-deviceS

B-deviceS

B-deviceS

D+D+VV BUSBUS = 5V = 5V

GNDGNDD-D-

3.3 V 3.3 V 3.3 V 3.3 V

D+D+

VV BUSBUS = 5V = 5V

GNDGNDD-D- B-device

SB-device

S

A-deviceM

A-deviceM

3.3 V 3.3 V

May 9, 2001 49


11. A-device sets/clears the B-devices MNP bit depending onwhether it wants to use the bus or not (thus allowing the B-deviceto request bus mastership)

11. A-device sets/clears the B-devices MNP bit depending onwhether it wants to use the bus or not (thus allowing the B-deviceto request bus mastership)

D+D+

VV BUSBUS = 5V = 5V

GNDGNDD-D- B-device

SB-device

S

A-deviceM

A-deviceM

3.3 V 3.3 V

May 9, 2001 50

ConclusionConclusion

Key Differences with USB 2.0 specification Compliance Current Status Resources Call to action

Key Differences with USB 2.0 specification Compliance Current Status Resources Call to action

May 9, 2001 51

Key DifferencesKey Differences

TP1 to TP2 limited to 1 ns – 3 ns in the USB 2.0 specification (allows for ribbon

cables to the front of a PC, for example) Output current 4 ma minimum Dual-role devices consume only 150 ua Number of devices typically supported

TP1 to TP2 limited to 1 ns – 3 ns in the USB 2.0 specification (allows for ribbon

cables to the front of a PC, for example) Output current 4 ma minimum Dual-role devices consume only 150 ua Number of devices typically supported

May 9, 2001 52

ComplianceCompliance

First pass USB 2.0 peripheral compliance program– Covers slave-only characteristics

Then the OTG compliance program – Test host capability & electrical characteristics– Test proper MNP support– Test user experience

First pass USB 2.0 peripheral compliance program– Covers slave-only characteristics

Then the OTG compliance program – Test host capability & electrical characteristics– Test proper MNP support– Test user experience

May 9, 2001 53

Current StatusCurrent Status

Release Candidate for revision 0.9

Compliance spec at revision 0.7

Release Candidate for revision 0.9

Compliance spec at revision 0.7

May 9, 2001 54

ResourcesResources

http://www.usb.org/members/onthego/

mail distribution list: [email protected]

http://www.usb.org/members/onthego/

mail distribution list: [email protected]

May 9, 2001 55

Call to ActionCall to Action

Get involved! Device class specs to make OTG universal!

– Printers– Mobile phones – Scanners– Cameras

Get involved! Device class specs to make OTG universal!

– Printers– Mobile phones – Scanners– Cameras

May 9, 20012 USB On-The-Go Kosta Koeman Cypress Semiconductor Kosta Koeman Cypress Semiconductor.

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Transcript of May 9, 20012 USB On-The-Go Kosta Koeman Cypress Semiconductor Kosta Koeman Cypress Semiconductor.