AT90USB646 datasheet(293/434 Pages) ATMEL

Part #	AT90USB646

Description	Microcontroller with 64/128K Bytes of ISP Flash and USB Controller

PDF	434 Pages

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Manufacturer	ATMEL [ATMEL Corporation]

Direct Link	http://www.atmel.com

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293 / 434 page

293

7593A–AVR–02/06

AT90USB64/128

23. USB Host Operating Modes

23.1 Pipe description

For the USB Host controller, the term of Pipe is used instead of Endpoint for the USB Device

controller. A Host Pipe corresponds to a Device Endpoint, as described in the USB specification:

Figure 23-1. Pipes and Endpoints in a USB system

In the USB Host controller, a Pipe will be associated to a Device Endpoint, considering the

Device Configuration Descriptors.

23.2 Detach

The reset value of the DETACH bit is 1. Thus, the firmware has the responsibility of clearing this

bit before switching to the Host mode (HOST set).

23.3 Power-on and Reset

The next diagram explains the USB host controller main states on power-on:

Figure 23-2. USB host controller states after reset

Host

Ready

Host

Idle

Device

disconnection

<any

other

state>

Device

connection

Clock stopped

Macro off

Device

disconnection

Host

Suspend

SOFE=1

SOFE=0

AT90USB646 Datasheet(PDF) 293 Page - ATMEL Corporation