AT43311 データシートの表示（PDF） - Atmel Corporation

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AT43311

USB Hub

Atmel Corporation 

USB Hub Description

Hub Repeater

The hub repeater is responsible for port connectivity setup

and tear-down. The repeater also supports exception han-

dling such as bus fault detection and recovery, and con-

nect/disconnect detection.

When a SOP token is detected on the upstream port,

Port0, the AT43311 determines the speed of the transfer.

A USB hub must not propagate a full speed transfer to a

low speed port due to the possible misinterpretation of the

data. The AT43311 will propagate the packet to all enabled

downstream ports.

Note: See USB Specification for further detail on bus

states

The AT43311 supports downstream data signaling at both

1.5 Mbps and 12 Mbps. Devices attached to the down-

stream ports are either full speed or low speed depending

on which data line (DP or DM) is pulled high. If a port is

enumerated as low speed, the output buffers operate at a

slew rate between 75 ns and 300 ns. The AT43311 will not

propagate any traffic to that port unless it is prefaced with a

preamble PID. Low speed data following the preamble PID

is propagated to both low and full speed devices. The

AT43311 will enable low speed drivers within four full-

speed bit times of the last bit of a preamble PID, and will

disable the drivers at the end of an EOP. The upstream

traffic from any port to the host is propagated by Port0

using the full speed 4-20 ns slew rate drivers.

All ports are independently driven and monitored on the DP

and DM pins. The AT43311 detects or generates the ‘J’,

‘K’, and SE0 bus signaling states. Each hub port has sin-

gle-ended and differential receivers on its DP and DM lines.

The ports’ I/O buffers comply to the voltage levels and drive

requirements as specified in the USB Specifications Revi-

sion 1.0.

The Hub Repeater implements a frame timer that is timed

by the 12 MHz USB clock and is reset every time an SOF

token is received from the Host.

Hub Controller

The hub controller manages and records the operations of

the AT43311. During enumeration, the controller sends the

host the configuration information. The controller also

allows the host to retrieve the status of the downstream

ports, and power the downstream ports. The controller

applies power to the downstream ports on a per port basis.

After configuration, the controller will enable the power to a

downstream port upon a SetPortPower command by the

host. The controller supports two endpoints and a Control

Status register.

Serial Interface Engine

The Serial Interface Engine (SIE) converts data between

the serialized USB format and usable data for the controller

and repeater. To carry out these tasks, the SIE is able to

detect or generate USB signaling. Once a valid operation is

detected, the SIE translates the data depending on the

operation.

During a reception, the SIE will use the high speed clock

supplied by the PLL to help synchronize and separate the

synchronization information from the data. The data must

be decoded before the SIE may supply the packet ID to the

controller and repeater.

The USB protocol uses Cyclical Redundancy Check

(CRC), Non Return to Zero Invert (NRZI) data encoding

and bit stuffing to improve the reliability of data transfers.

The SIE must decode the NRZI and strip off the stuffed bit

to determine the actual data. The CRC information will be

used by the SIE to determine if a transmission error has

occurred. If an error has occurred, the SIE will correct the

data using CRC algorithms.

Control Status Register

Bit Function

0

Hub configuration status

1

Hub remote wakeup status

2

Endpoint0 STALL status

3

Endpoint1 STALL status

Value

0

1

0

1

0

1

0

1

4

AT43311

Description

Set to 0 or 1 by a Set_Configuration Request

Hub is not currently configured

Hub is currently configured

Set to 0 or 1 by ClearFeature or SetFeature request

Default value is 0

Hub is currently not enabled to request remote wakeup

Hub is currently enables to request remote wakeup

Endpoint0 is stalled

Endpoint0 is stalled

Endpoint1 is not stalled

Endpoint1 is stalled

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