ATMEL AT43310 Datasheet

Features

• Bus Powered Hub Controller

• Full Compliance with USB Spec Rev 1

• Full Speed USB Host Interface

• Four Downstream Ports

• Downstream Support for Full Speed and Low Speed Transfer Rates

• Continual Monitoring of Port by System Host

• Individual Port Power Control

• USB Connection Status Indicators

• 6 MHz Oscillator with On-Chip PLL

Description

The AT43310 is a fully compliant USB hub chip with 5 ports, one upstream port and
four full/low-speed d ownstrea m por ts. The AT4331 0 can be us ed as a stand alone or
can provide a simple and quick method of adding USB ports to an existing device.

As a repeater, the AT43310 provides upstream connectivity between the selected
function and the hos t. Con nec ti vi ty i nv olv es s et ting up and tearing do wn co nne cti ons ,
handling bus faults, recovering from bus faults and detecting downstream device con­nections and disconnections.

The AT43310 may also act as a hub con troller managing the hub operations and
recording the status of the hub, bus transactions, and downstream ports. In this mode,
the AT43310 tracks and gene rates the bu s enumer ation , provide s confi guratio n infor ­mation to the host, prov ides indivi dual port stat us to the host, an d controls the port
operation based on host commands.

AT43310

USB Hub

AT43310

Pin Configurations

SOIC/DIP/Cerdip

PWR2
PWR3
PWR4

VCC5

VSS
OSC1
OSC2

LFT

VCCA

OVL4
OVL3
OVL2
OVL1

VREF

GND

STAT4

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16

32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17

PWR1
DP4
DM4
DP3
DM3
GND
DP2
DM2
VCC3
DP1
XDM1
DP0
DM0
STAT1
STAT2
STAT3

Rev. 0901A-A–01/98

1

Block Diagram

Note: This document assumes that the reader is familiar with the Universal Serial Bus and therefore only describes the unique fea-

tures of the AT43310 chip. For detailed information about the USB and its operation, the reader should refer to the Universal
Serial Bus Specification Version 1.0, January 19, 1996.

2

AT43310

AT43310

Pin Description

Pin Description Pin Type Description

OSC1 I Oscillator Input. Input to the inverting 6 MHz oscillator amplifier.
OSC2 O Oscillator Output. Output of the inverting oscillator amplifier.

LFT I

VREF I Reference Voltage. This is an input pin that should be connected to an external

DP0 B Upstream Plus USB I/O. This pin should be connected to VCC3 through an external

DM0 B Upstream Minus USB I/O
DP[1:4] B Port Plus USB I/O. These pins should be connected to VSS through external 1.5K Ω

DM[1:4] B

OVL[1:4]

PWR[1:4]

I Port Overload. These are the input signals used to indicate to the AT43310 that there

OD Power Switch. These are the output signals used to enable or disable the external

PLL Filter. For proper operation of the PLL, this pin should be connected through a
100 Ω resistor and 10 nF capacitor to ground (V
(see Figure 1–Power Supply Connection).

voltage source. VREF is used internally as the reference voltage by the overload
protection circuit to decide whether there is a problem with a port’s power supply.

1.5K Ω pullup resistor. DP0 and DM0 form the full speed differential signal pin pairs
connected to the Host Controller or an upstream Hub.

resistors. DP[1:4] and DM[1:4] are the differential signal pin pairs to connect
downstream USB devices.

Port Minus USB I/O. These pins should be connected to VSS through external 15K Ω
resistors. DP[1:4] and DM[1:4] are the differential signal pin pairs to connect
downstream USB devices.

is a power supply problem with the port. If OVL
the corresponding PWR[1:4]

voltage regulator supplying power to the port. PWR[1:4]
supply problem is detected at OVL[1:4]

For proper operation of PWR[1:4]
required.

pin and report the status to the USB Host.

.

, an external pull-up resistor of 10K Ω to VCC5 is

) in parallel with a 2.2 nF capacitor

SS

is asserted, the AT43310 will assert

is de-asserted when a power

STAT[1:4]

V

CC3

V

CC5

V

CCA

GND V Ground

O Connect Status. These are output pins indicating that a port is properly connected.

STAT[1:4]
V 3.3V Power Supply, used for the USB interface
V 5V Power Supply, main power supply for the AT43310
V 5V Analog Power Supply

is asserted when the port is enabled.

3

USB Hub Description

Hub Repeater

The hub repeater i s respo nsible for port co nnectivi ty setup
and tear-down. The repeater also supports exception han­dling such as bus fault detection and re covery, and con­nect/disconnect detection.

When a SOP token is detec ted on the upstream port ,
Port0, the AT43310 dete rmines the s peed 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 AT43310 will propagate the packet to all enabled
downstream ports.

Note:

See USB Specification for further detail on bus

states
The AT43310 supports downstream data signaling at both

1.5 Mbps and 12 Mbps. Devic es attached to the down­stream ports are either full speed or low speed depending
on which data line (DP or DM) is pulled hi gh. If a por t is
enumerated as low speed, the output buffers operate at a
slew rate between 75 ns and 300 ns. The AT43310 wi ll not
propagate any traffic to that port unless it is prefaced with a
preamble PID. Low speed d ata foll owing th e preambl e PID
is propagated to both low and full speed devices. The
AT43310 will enable low speed drivers within four full­speed bit time s of the la st bit of a preamb le PID, an d will
disable the driv ers at the end of an E OP. The upstr eam
traffic from any port t o the host is p ropagated by Po rt0
using the full speed 4-20 ns slew rate drivers.

All ports are independently driven and monitored on the DP
and DM pins. The AT43310 detects or generates the ‘J’,
‘K’, and SE 0 bus signal ing st ates. E ach hu b port has s in­gle-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 Revi­sion 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 control ler man ages an d recor ds the operati ons of
the AT43310. During enumeration, the contro ller send s the
host the configuration information. The controller also
allows the host to re trieve the stat us of the downstre am
ports, and power the downs tream ports. The contr oller
applies power to the do wns tream por ts on a pe r por t ba si s.
After configuration , the c ontrol le r will e nab le 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 i nformatio n from th e data. T he data mu st
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) d ata encoding
and bit stuffing to im prove th e reli ability of data trans fers.
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 transmis sion error has
occurred. If an error has occurred, the SIE will corr ect the
data using CRC algorithms.

Control Status Register

Bit Function Value Description

0 Hub configuration status

1 Hub remote wakeup status

2 Endpoint0 STALL status 0

3 Endpoint1 STALL status 0

4

AT43310

0
1

0
1

1

1

Set to 0 or 1 by a Set_Configuration Request

Set to 0 or 1 by ClearFeature or SetFeature request
Default value is 0

Endpoint0 is stalled
Endpoint0 is stalled

Endpoint1 is not stalled
Endpoint1 is stalled

Hub is not currently configured
Hub is currently configured

Hub is currently not enabled to request remote wakeup
Hub is currently enables to request remote wakeup

AT43310

Endpoint0

Endpoint0 is the A T43310’ s defaul t endpoin t used for enu­meration of the Hub and exchange of configuration infor­mation and requests between the Host and the AT43310.
Endpoint0 supports control transfers.

Standard USB Device Requests and class-specific Hub
Requests are supported through Endpoint0.

The Hub Controller supports the fol lowing descriptors
through Endpoint0 (Descriptors are described in detail in
the Descriptors Section of this document):

• Device Descriptor

• Configuration Descriptor

• Interface Descriptor

• Endpoint Descriptor

• Hub Descriptor

Endpoint1

Endpoint1 is used by the Hub Controller to send status
change information to th e Host. Endpoint1 supports inter­rupt transfers.

The Hub Controll er samples th e changes at the end of
every frame at time marker EO F2 in preparation for a
potential data transfer in the subsequent frame. The sam­pled information is store d as a by te in S tatus C hange Re g­ister using a bitmap scheme.

Each bit in the Status Chan ge Reg ister co rres po nds to one
port as shown below.

An IN Token packet from the Hos t to E nd poi nt1 ind icate s a
request for port change status. If the Hub has not detected
any change on the por ts or a ny cha nges in the hub itself ,
then all bits in this re giste r will be 0 and th e Hub Contro ller
will return a NAK to requests on Endpoint1. If a change in
the port status exists, the Hub Controller will transfer the

whole byte. The Hub Controller will continue to report a sta­tus change when polled until that particular change has
been removed by a Clea rPortFeature reques t from the
Host. No status change will be reported by Endpoint1 until
the AT43310 has been enumerated and configured by the
Host through Endpoint0.

Power Management

A hub is allowed to draw up to 500 mA from the host or
upstream hub. The AT4 3310’s i tsel f and its ex tern al circu it
except for the downstream ports consume less than 100
mA. Therefore 100 mA is available for e ach of the hub’s
downstream devices. The power supplied to each port is
individually monitored and controlled by AT43310.

The USB specifications requires that the voltage drop at
the power switch be no more than 10 0 mV. Caref ul design
and selection of the pow er swi tch is req uired to meet this
specifications . This is best achie ved by using a MO SFET
switch with a very low on resistance. If the port power are
switched individuallly, this resistance must be 1Ω or less
under the worst case cond ition to assure that even if a
downstream device dissipates 100mA the drop across the
switch is less than 100 mV. If the downstream devices are
switched in common, the switch resis tance must be no
more than 250mΩ.

A suitable MOSFET switch for a AT43310 based hub is a P
channel enhanc ement mode MOSF ET. The conditio n of
the port’s power is monitored at the output side of the
PMOS switch which is connected to the port’s OVLx# pin.
Whenever an overcurrent condition occurs, the MOSFET
switch’s internal resistance c auses the output volta ge to
drop. If the MOSFET’s output voltage drops to less than the
voltage at the VREF voltage reference pin, the AT43310
interpretes this as an overcurrent condition. The AT43310
does internal filte ring to make sure that spur ious or swi tch­ing transients are ignored. If a true overcurrent condition

Status Change Register

Bit Function Value Meaning

0 Hub status change 0

1

1 Port1 status change 0

1

2 Port2 status change

3 Port3 status change

4 Port4 status change

5-7 Reserved 0 Default values

0
1

0
1

0
1

No change in status
Change in status detected

No change in status
Change in status detected

No change in status
Change in status detected

No change in status
Change in status detected

No change in status
Change in status detected

5

Figure 1.

Power Supply Connection

exists, AT43310 re moves the power from that port by de­activating the port’s PWRx# pin and reports the condition to
the Host.

Figure 1 shows an example of the power supply connection
for a typical AT43310 port.

Port [1:4] Power Control

Each port has signals for port power management and for
port status feedback (PWR[1:4]
The AT43310 monitors and switches the power to each
port individually.

PWR[1:4]
the downstream ports. The AT43310 asserts a low value to
ports PWR[1:4]
power up, reset, and initialization of the Hub, PWR[1:4]
in-active. PWR[1:4 ]
Hub to power the port through the SetPortPower = ON
command. Additionally PWR[1:4]
when an overcurrent condition is detected at the port.

For proper operation of PWR[1:4]
tor to V
power to the port, any switch with a low voltage drop with
full power appl ied is a ccepta ble. The A T43 310 is des igned
for a simple , low cost P -channel MOSFET to use a s the
switch.

To detect a port overload, the AT43310 compares OVL[1:4]
to a common VREF defined by the designer.

are open drain outputs that control the power to

to turn on the power to the port. During

is asserted when the Hos t i ns truc ts the

is required for PWR[1:4] pins. To control the

CC5

, OVL[1:4], and STAT[1:4]).

is

is de-asserted by the Hub

, an external pull-up resis-

OVL[1:4]
respective downstream po rt. If OVL[1:4]
reference voltage VREF for more than 1 ms, the AT43310
treats the drop in voltage as a fault condition on the port’s
power supply. Upon this fault condition, the AT43310 sets
the port’s PORT_OVER_CURRENT status bit and the
port’s C_PORT_OVER_CURRENT bit. The AT43310 will
additionally shut off the power to the port by de-activating
the port’s PWR[1:4]

The STAT [1:4]
tion. STAT[1:4]
device is properly connected to the port. An LED and series
resistor connected to STAT[1:4]
visual feedback. The default state of STAT[1:4]
After a port is enabled AT43310 will assert the port’s
STAT[1:4]

should be attached to the power supply of the

drops below the

signal.

pins are not required by the USB specifica-

provide feedback to the user whenever a

can be used to provide

is inactive.

.

Oscillator and Phase-Locked-Loop

To reduce EMI and power dissip ation in the system, the
AT43310 on-chip oscillator is designed to operate with a 6
MHz external crystal. An on-chip PLL generates the high
frequency for the clock/data separator of the Serial Inter­face Engine. In the suspe nded state, the oscillato r circuitr y
is turned off.

A 6 MHz parallel resonance quartz crystal with a load
capacitance of approximately 10 pF is recommended. If the
crystal load capacitor is larger, external capacitors added to

6

AT43310

AT43310

pins OSC1 and OSC2 are recommended. The values for
these capacitors depends on th e crystal and the layout o f
the board, but typically are 33 pF at OSC1 a nd 47 pF at
OSC2. If the crystal used cannot tolerate the drive levels of
the oscillator, a series resistor between OSC2 and the crys­tal pin may be used.

Figure 2 shows how to properly connect the oscillator for
the AT43310. Ceramic resonators are not recommended
due to the frequency stability required by the USB specifi­cation (0.25%).

If desired, the cloc k can be ex ternally sourc ed. To clock
externally, connect the clock source to the OSC1 pin, while
leaving the OSC2 pin floating. The switching level at the
OSC1 pin can be as lo w as 0.47 V (see e lectric al spec ifica­tions). A CMOS d ev ice is required to drive thi s pi n to m ai n­tain good noise margins at the low switching level.

For proper operation of the PLL, see Figure 2-Ocscillator
and PLL Connection.

To provide the best operating condition for the AT43310,
careful consideration of the power supply connections are

Figure 2.

Oscillator and PLL Connection

recommended. Use short, low impedance connections to

, V

, V

all power supply lines: V
µF decoupling capacitors of high quality adjacent to the
device pins.

CC5

CC3

, and VSS with 0.1

CCA

Descriptors

The Hub Controller supports the following standard USB
descriptors: Dev ice, Conf igurat ion, Interf ace, and E ndpoint
Descriptors, as well as th e class sp ecific Hub Descrip tor.
All the required Standard Requests and Hub Class-Specific
Requests are supported by the AT43310’s Hub Controller.

7

Device Descriptor

The Device Descriptor provides general information about the AT43310 Hub.

Offset Field Description Size (bytes) Value

0 bLength Define size of descriptor = 18 bytes 1 12H
1 bDescriptorType Device descriptor type 1 00H
2 bcdUSB USB Spec. Release Number = Rev 1.0 2 00H

4 bDeviceClass Class code = HUB_CLASSCODE = 09 1 09H
5 bDeviceSubClass Subclass code 1 00H
6 bDeviceProtocol Protocol code 1 00H
7 wMaxPacketSize0 Max. packet size for Endpoint0 = 8-bytes 1 08H
9 idVendor Vendor ID = Atmel Corporation 2 EBH

10 idProduct Product ID = AT43310 2 10H

01H

03H

33H

12 bcdDevice

14 iManufacturer Index of string descriptor describing

15 iProduct Index of string descriptor describing product =

16 iSerialNumber Index of string descriptor describing device’s

17 bNumConfigurations Number of possible configurations = 1 1 01H

Device release number

Example:Rev A0YY = 01ZZ = 00

Rev B1YY = 02ZZ = 01

manufacturer = not supported

not supported

serial no. = not supported

2 ZZH

YYH

100H

100H

100H

8

AT43310