2

AT43USB353M

3307AS–USB–02/03

Overview

The Atmel AT43USB353M is a full-speed USB AVR-based microcontroller with a full-speed

USB 2.0 compliant embedded hub especially suitable for use in applications requiring Analog-

to-Digital converters (ADCs) and PWMs such as in force feedback game controllers. The USB

hub has 3 downstream ports, one of which is permanently attached to the USB function. The

USB function controller has its own device address and endpoints. In game controller applica-

tions, the two external downstream USB ports can be used to connect other devices such as

headphone sets for voice commands flash memory modules or any other USB device.

The MCU of the AT43USB353M is a high performance 8-bit AVR RISC that operates at a

clock frequency of 12 MHz or 24 MHz. Its program memory is a 24-Kbyte mask programmable

ROM and its data memory is 1-Kbyte SRAM. The ADC has a minimum conversion time of

12 ms that together with the 12 input channels should cover even the most demanding game

controllers such as gamepads, joysticks and racing wheels. The two PWM outputs can be pro-

grammed for 8-, 9- or 10-bit resolution for applications requiring force feedback. The 15

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 function has one control endpoint and three additional programmable endpoints,

each with their own FIFOs. Two of the endpoints have a 64-byte FIFO each, while the third

has an 8-byte FIFO. The USB hardware supports the physical and link layers of the USB pro-

tocol while the transaction layer function must be implemented in the MCU’s firmware. The

AVR architecture was developed to be efficiently programmed in C and without loss in

performance.

The AT43USB353M is binary-compatible with the AT43USB355. Firmware written for the

AT43USB355 will run on the AT43USB353M without modification as long as only features

common to both devices are used.

Development

Support

The AT43USB353M uses the same program and development tools as the AT43USB355 and

other Atmel AVR microcontrollers including: C compilers, macro assemblers, program debug-

gers/simulators, in-circuit emulators. The development kit is the AT43DK355, which comes

with USB firmware library and sample source code for the most common USB applications.