Atmel SAM4L Xplained Pro Starter Kit Atmel ATSAM4L-XSTK ATSAM4L-XSTK Hoja De Datos

42023E–SAM–07/2013

USBFSM

Read-Only

0x082C

0x00000009

This field indicates the state of the USBC.

For Device mode it should always read 9.

31

30

29

28

27

26

25

24

-

-

-

-

-

-

-

-

23

22

21

20

19

18

17

16

-

-

-

-

-

-

-

-

15

14

13

12

11

10

9

8

-

-

-

-

-

-

-

-

7

6

5

4

3

2

1

0

-

-

-

-

DRDSTATE

0

a_idle state: this is the start state for A-devices (when the ID pin is 0)

1

a_wait_vrise: In this state, the A-device waits for the voltage on VBUS to rise above the A-
device VBUS Valid threshold (4.4 V).

2

a_wait_bcon: In this state, the A-device waits for the B-device to signal a connection.

3

a_host: In this state, the A-device that operates in host mode is operational.

4

a_suspend: The A-device operating as a host is in the suspend mode.

5

a_peripheral: The A-device operates as a peripheral.

6

a_wait_vfall: In this state, the A-device waits for the voltage on VBUS to drop below the A-
device Session Valid threshold (1.4 V).

7

a_vbus_err: In this state, the A-device waits for recovery of the over-current condition that 
caused it to enter this state.

8

a_wait_discharge: In this state, the A-device waits for the data usb line to discharge (100 us).

9

b_idle: this is the start state for B-device (when the ID pin is 1).

The USBC controller operates in device mode.

10

b_peripheral: In this state, the B-device acts as the peripheral.

11

b_wait_begin_hnp: In this state, the B-device is in suspend mode and waits until 3 ms before 
initiating the HNP protocol if requested.