AT43USB321

2

Figure 1. AT43USB321 Block Diagram

Development Support

The AT4USB321 uses the same program and development

tools as the Atmel AVR microcontrollers including: C com-

pilers, macro assemblers, program debuggers/simulators,

in-circuit emulators. The AT43USB321 is binary compatible

with the AT43320 and the two share the same develop-

ment kit, which includes firmware source code for the most

common USB applications.

Applications

The attached diagram shows an applicatio n of th e

AT43USB321 in a monitor as a hub with two embedded

functions: a monitor display controller and IR receiver. The

number of external downstream ports of the hub is pro-

grammable from one to four. The hub can be self-powered

or bus-powered. In most cases, hubs in the monitors will be

self-powered because of the readily availability of the

power supply and its more versatility.

In this example, the AT43USB321 interfaces to the moni-

tor’s microcontroller, the host microcontroller, through an

as DDC2Bi. The firmware inside the AT43USB321 acts as

the translator between the host system and the host micro-

controller. This function can be performed without any

modification in the host microcontroller’s firmware resulting

in a very flexible way of adding USB capability in any moni-

tor. The IR receiver function is also implemented in

firmware also and can support any consumer type IR proto-

col that uses a frequency in the range of up to 52 kHz.

HUB AND

DEVICE

CONTROLLER

GENERAL PURPOSE IO

PORT4

PORT3

PORT2

PORT1

LFT

OSC1

OSC2

6/12M

DP0

DM0

PA[0:7]

PB[0:7]

PD0/RXD

PD1/TXD

PD2/INT0

PD3/INT1

CEXT

VCC

VSS

DP4

DM4

DP3

DM3

DP2

DM2

DP1

DM1

OVC

PWR

RST

OSC

&

PLL

SERIAL

INTERFACE

ENGINE

HUB

REPEATER