ATmega16U4 datasheet(279/408 Pages) ATMEL

279 / 408 page

279

7766D–AVR–01/09

ATmega16U4/ATmega32U4

• 7-4 - Reserved

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

• 3 - RSTCPU - USB Reset CPU bit

Set this bit to 1 by firmware in order to reset the CPU on the detection of a USB End of Reset

signal (without disabling the USB controller and Attached state). This bit is reset when the USB

controller is disabled, but is not affected by the CPU reset generated after a USB End of Reset

(remains enabled).

• 2 - LSM - USB Device Low Speed Mode Selection

When configured USB is configured in device mode, this bit allows to select the USB the USB

Low Speed or Full Speed Mod.

Clear to select full speed mode (D+ internal pull-up will be activate with the ATTACH bit will be

set).

Set to select low speed mode (D- internal pull-up will be activate with the ATTACH bit will be

set). This bit has no effect when the USB interface is configured in HOST mode.

• 1- RMWKUP - Remote Wake-up Bit

Set to send an “upstream-resume” to the host for a remote wake-up (the SUSPI bit must be set).

Cleared by hardware when signalling finished. Clearing by software has no effect.

See Section 22.10, page 271 for more details.

• 0 - DETACH - Detach Bit

Set to physically detach de device (disconnect internal pull-up on D+ or D-).

Clear to reconnect the device. See Section 22.9, page 270 for more details.

• 7 - Reserved

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

• 6 - UPRSMI - Upstream Resume Interrupt Flag

Set by hardware when the USB controller is sending a resume signal called “Upstream

Resume”. This triggers an USB interrupt if UPRSME is set.

Shall be cleared by software (USB clocks must be enabled before). Setting by software has no

effect.

• 5 - EORSMI - End Of Resume Interrupt Flag

Set by hardware when the USB controller detects a good “End Of Resume” signal initiated by

the host. This triggers an USB interrupt if EORSME is set.

Shall be cleared by software. Setting by software has no effect.

• 4 - WAKEUPI - Wake-up CPU Interrupt Flag

Bit

65432

UPRSMI

EORSMI

WAKEUPI

EORSTI

SOFI

SUSPI

UDINT

Read/Write

Initial Value

00000

ATmega16U4 Datasheet(PDF) 279 Page - ATMEL Corporation

ATmega16U4 Datasheet(HTML) 279 Page - ATMEL Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL