AT43USB326-AU Atmel, AT43USB326-AU Datasheet - Page 62

• Manufacturer Part Number: AT43USB326-AU
• Description: IC USB KEYBOARD CTRLR 48LQFP
• Manufacturer: Atmel
• Series: AVR®r

Specifications of AT43USB326-AU

• Applications: Keyboard Controller
• Core Processor: AVR
• Program Memory Type: Mask ROM (16 kB)
• Controller Series: AT43USB
• Ram Size: 512 x 8
• Interface: USB
• Number Of I /o: 32
• Voltage - Supply: 4.4 V ~ 5.25 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 48-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

USB Hub
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AT43USB326
The hub in a USB system provides for the electrical interface between USB devices and the
host. The major functions that the hub must supports are:
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A hub consists of two major components: a hub repeater and a hub controller. The hub
repeater is responsible for:
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The Hub Controller is responsible for:
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The first two tasks of the hub are similar to that of a USB function and are described in detail in
the following section. The descriptions will cover the features of the AT43USB326's hub and
how to program it to make a USB-compliant hub.
Control transactions for the hub control endpoint proceed exactly the same way as those
described for the embedded function. The operation of the hub's endpoint 1 is fully imple-
mented in the hardware and does not need any firmware support. Any status changes within
the hub will automatically update hub endpoint 1, which will be sent to the host at the next IN
token that is addressed to it. If no change has occurred, the interrupt endpoint will respond
with a NAK.
Connectivity
Power management
Device connect and disconnect
Bus fault detection and recovery
Full speed and low speed device support
Providing upstream connectivity between the selected device and the Host
Managing connectivity setup and tear-down
Handling bus fault detection and recovery
Detecting connect/disconnect on each port
Hub enumeration
Providing configuration information to the host
Providing status of each port to the host
Controlling each port per host command
3313D–USB–04/06