USBN9603 Datasheet, PDF (23/60 Pages) National Semiconductor (TI) – Universal Serial Bus Full Speed Function Controller with Enhanced DMA Support

6.0 Functional Description (Continued)
suspend_det &
set_suspend
NodeOperational
10b
set_oper
reset_det & set_reset
hw/sw reset
resume_compl &
set_oper
NodeReset
00b
resume_det &
set_oper
NodeResume
01b
NodeSuspend
11b
local_event & sd5_detect &
clear_suspend
reset_det &set_reset
Bold Italics = Transition initiated by firmware
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.
State
Transition
set_reset
set_suspend
set_oper
clear_suspend
reset_det
local_event
sd5_det
suspend_det
resume_det
resume_compl
Figure 18. Node Functional State Diagram
Table 3. Functional States
Condition Asserted
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.
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.
Node Functional State register NFS[1:0] bits are written with 10_b
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 in the ALTEV register is set to 1
A local event that should wake up the USB.
SD5 in the ALTEV register is set to 1.
SD3 in the ALTEV register is set to 1.
RESUME in the ALTEV register is set to1.
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.
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