AT90USB646 datasheet(298/459 Pages) ATMEL

298 / 459 page

298

7593H–AVR–11/08

ATmega32U6/AT90USB64/128

23.16.1

General USB Host registers

• 7-3 - Reserved

The value read from these bits is always 0. Do not set these bits.

• 2 - RESUME - Send USB Resume

Set this bit to generate a USB Resume on the USB bus.

Cleared by hardware when the USB Resume has been sent. Clearing by software has no effect.

This bit should be set only when the start of frame generation is enable (SOFEN bit set).

• 1 - RESET - Send USB Reset

Set this bit to generate a USB Reset on the USB bus.

Cleared by hardware when the USB Reset has been sent. Clearing by software has no effect.

Refer to the USB reset section for more details.

• 0 - SOFEN - Start Of Frame Generation Enable

Set this bit to generate SOF on the USB bus in full speed mode and keep-alive in low speed

mode.

Clear this bit to disable the SOF generation and to leave the USB bus in Idle state.

• 7 - Reserved

The value read from these bits is always 0. Do not set these bits.

• 6 - HWUPI

Host Wake-Up Interrupt

Set by hardware when a non-idle state is detected on the USB bus.This interrupt should be

enable only to wake up the CPU core from power down mode.

Shall be clear by software to acknowledge the interrupt. Setting by software has no effect.

• 5 - HSOFI - Host Start Of Frame Interrupt

Set by hardware when a SOF is issued by the Host controller. This triggers a USB interrupt

when HSOFE is set. When using the host controller in low speed mode, this bit is also set when

a keep-alive is sent.

Shall be cleared by software to acknowledge the interrupt. Setting by software has no effect.

Bit

7654

-----

RESUME

RESET

SOFEN

UHCON

Read/Write

R/W

Initial Value

0000

Bit

6543210

HWUPI

HSOFI

RXRSMI

RSMEDI

RSTI

DDISCI

DCONNI

UHINT

Read/Write

R/W

Initial Value

0000000

AT90USB646 Datasheet(PDF) 298 Page - ATMEL Corporation

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