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AT43USB355

2603BS–USB–01/02

Overview

The Atmel AT43USB355 is a full speed USB AVR-based microcontroller with a USB 1.1 com-

pliant embedded hub especially suitable for use in game controllers. The USB hub has 3

downstream ports, one of which is permanently attached to the USB function. The USB func-

tion controller has its own device address and endpoints. In game controller applications, the

two external downstream USB ports can be used to connect other devices such as head-

phones sets for voice commands of games, Flash memory modules, or any other USB device.

The A-to-D converters have a minimum conversion time of 12 µs that together with the 12-

input channel should cover even the most demanding game controllers such as gamepads,

joysticks and racing wheels. The two PWM outputs can be programmed for 8-, 9- or 10-bit res-

olution for applications requiring force feedback. The 27 general-purpose programmable I/O

pins provide generous inputs for the various buttons and switches and LED indicators that are

being used in increasing numbers in today’s game controllers.

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

lers, and an interface to the microcontroller. The USB hardware of the AT43USB355 supports

the physical and link layers of the USB protocol while the transaction layer and hub controller

functions must be implemented in the microcontroller’s firmware. If the application does not

require a hub, it can be disabled. The AVR architecture was developed to be programmed in C

efficiently and without loss in performance.

There are two versions of the chip. The AT43USB355E has a SRAM program memory that is

automatically loaded from an external serial Flash/EEPROM during power on reset. The

AT43USB355M stores its firmware in a masked ROM. The two versions are pin and function

compatible.

Development

Support

The AT43USB355 uses the same program and development tools as the Atmel AVR micro-

controllers including: C compilers, macro assemblers, program debuggers/simulators, in-

circuit emulators. A development kit is also available including firmware source code for the

most common USB applications.