SAM4L Datasheet, PDF (375/1185 Pages) ATMEL Corporation – ATSAM ARM-based Flash MCU

17.7.1.10 Finite State Machine Status Register
Register Name:
USBFSM
Access Type:
Read-Only
Offset:
0x082C
Reset Value:
0x00000009
ATSAM4L4/L2
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
• DRDSTATE: Dual Role Device State
This field indicates the state of the USBC.
For Device mode it should always read 9.
DRDSTATE
0
1
2
3
4
5
6
7
8
9
10
11
Description
a_idle state: this is the start state for A-devices (when the ID pin is 0)
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).
a_wait_bcon: In this state, the A-device waits for the B-device to signal a connection.
a_host: In this state, the A-device that operates in host mode is operational.
a_suspend: The A-device operating as a host is in the suspend mode.
a_peripheral: The A-device operates as a peripheral.
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).
a_vbus_err: In this state, the A-device waits for recovery of the over-current condition that
caused it to enter this state.
a_wait_discharge: In this state, the A-device waits for the data usb line to discharge (100 us).
b_idle: this is the start state for B-device (when the ID pin is 1).
The USBC controller operates in device mode.
b_peripheral: In this state, the B-device acts as the peripheral.
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.
42023C–SAM–02/2013
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