Datasheet

6.0 Functional Description (Continued)
23
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Figure 18. Node Functional State Diagram
Table 3. Functional States
State
Transition
Condition Asserted
set_reset
Node Functional State register NFS[1:0] bits are written with 00
b
The firmware should only initiate set_reset if RESET in the ALTEV register is set.
set_suspend
Node Functional State register NFS[1:0] bits are written with 11
b
The firmware should only initiate set_suspend if SD3 in the ALTEV register is set.
set_oper
Node Functional State register NFS[1:0] bits are written with 10
b
clear_suspend
Node Functional State register NFS[1:0] bits are written with 01
b
The firmware should only initiate clear_suspend if SD5 in the ALTEV register is set.
reset_det RESET in the ALTEV register is set to 1
local_event A local event that should wake up the USB.
sd5_det SD5 in the ALTEV register is set to 1.
suspend_det SD3 in the ALTEV register is set to 1.
resume_det RESUME in the ALTEV register is set to1.
resume_compl
The node should stay in NodeResume state for at least 10mS and then must enter
USB Operational state to detect the EOP from the host, which terminates this Remote
Resume operation. EOP is signalled when EOP in the ALTEV register is set to 1.
10b
NodeOperational
00b
NodeReset
01b
NodeResume
11b
NodeSuspend
reset_det &set_reset
reset_det & set_reset
hw/sw reset
local_event & sd5_detect &
resume_det &
suspend_det &
set_suspend
resume_compl &
set_oper
Bold Italics = Transition initiated by firmware
set_oper
set_oper
clear_suspend
Notes:
1. When the node is not in NodeOperational state, all registers are frozen with the exception of the endpoint con-
troller state machines, and the TX_EN, LAST and RX_EN bits which are reset.
1. In NodeResume state, resume signaling is propagated upstream.
2. In NodeSuspend state, the node may enter a low power state and is able to detect resume signaling.
Obsolete