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Features

Overview

The Atmel AT43USB321 is a single-chip microcontroller based USB hub with an

embedded function and a 16K byte masked ROM. The USB hub has five downstream

ports, one of which is permanently attached. Internally the AT43320 consists of a USB

hub and function interface, a hub repeater, and a high-performance, efficient 8-bit

RISC microcontroller. The hub and peripheral device controller function is imple-

mented in the microcontoller’s firmware. To the USB host, the embedded function

appears as an attached port of the hub with its own device address and endpoints.

The AT43USB321 can also be configured as a USB function without the hub.

The USB hardware block consists of a USB transceiver, SIE, hub repeater, endpoint

controllers, and an interface to the microcontroller. The USB hardware interfaces to

the USB host at the transaction level. The CPU of the microcontroller is based on the

Atmel AVR microcontroller. The AVR architecture was developed to be programmed

in C efficiently and with maximum performance.

Full-speed USB

Hub/Function

Microcontroller

AT43USB321

Rev. 1442A–08/99