Datasheet

685
32072H–AVR32–10/2012
AT32UC3A3
27.8.1.10 Finite State Machine Status Register
Register Name: USBFSM
Access Type: Read-Only
Offset: 0x082C
Read Value: 0x00000009
• DRDSTATE
This field indicates the state of the USBB.
31 30 29 28 27 26 25 24
--------
23 22 21 20 19 18 17 16
--------
15 14 13 12 11 10 9 8
--------
76543210
- - - - DRDSTATE
DRDSTATE Description
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).
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.
12
b_wait_discharge: In this state, the B-device waits for the data usb line to discharge (100 us)
before becoming Host.