at43usb355 ATMEL Corporation, at43usb355 Datasheet - Page 90

• Manufacturer Part Number: at43usb355
• Description: At43usb355 Full-speed Usb Microcontroller With Embedded Hub, Adc And Pwm
• Manufacturer: ATMEL Corporation

USB Hub
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AT43USB355
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 Controller are similar to that of a USB function and will not be
described in detail in the following section. The descriptions will cover the features of the
AT43USB355's hub and how to program it to make a USB-compliant hub.
Control transactions for the Hub Control End-point proceed exactly the same way as those
described for the embedded function. The operation of the hub's End-point 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 End-point 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 end-point 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
2603G–USB–04/06