AT43USB325E-AC Atmel, AT43USB325E-AC Datasheet - Page 81

• Manufacturer Part Number: AT43USB325E-AC
• Description: IC USB KEYBOARD CTRLR HUB 64LQFP
• Manufacturer: Atmel
• Series: AVR®r

Specifications of AT43USB325E-AC

• Applications: Keyboard Controller
• Core Processor: AVR
• Program Memory Type: SRAM (16 kB)
• Controller Series: AT43USB
• Ram Size: 512 x 8
• Interface: SPI, 3-Wire Serial
• Number Of I /o: 42
• Voltage - Supply: 4.4 V ~ 5.25 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 64-LQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

8.4
3355C–USB–4/05
USB Hub
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:
A hub consists of two major components: a hub repeater and a hub controller. The hub repeater
is responsible for:
The Hub Controller is responsible for:
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 AT43USB325'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 implemented
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
AT43USB325
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