CP3UB17G38 NSC [National Semiconductor], CP3UB17G38 Datasheet - Page 66

• Manufacturer Part Number: CP3UB17G38
• Description: CP3UB17 Reprogrammable Connectivity Processor with USB Interface
• Manufacturer: NSC [National Semiconductor]

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15.0 USB Controller
The USB node is an integrated USB node controller that fea-
tures enhanced DMA support with many automatic data
handling features. It is compatible with USB specification
versions 1.0 and 1.1.
It integrates the required USB transceiver, a Serial Interface
Engine (SIE), and USB endpoint (EP) FIFOs. Seven end-
point pipes are supported: one for the mandatory control
endpoint and six to support interrupt, bulk, and isochronous
endpoints. Each endpoint pipe has a dedicated FIFO, 8
bytes for the control endpoint and 64 bytes for the other end-
points.
15.1
15.1.1
At any given time, the USB node is in one of the following
states
The NodeSuspend, NodeResume, or NodeReset line con-
dition causes a transition from one operating state to anoth-
er. These conditions are detected by specialized hardware
and reported in the Alternate Event (ALTEV) register. If in-
terrupts are enabled, an interrupt is generated on the occur-
rence of any of the specified conditions.
In addition to the dedicated input to the ICU for generating
interrupts on these USB state changes, a wake-up signal is
sent to the MIWU (see Section 13.0) when any activity is de-
tected on the USB, if the bus was in the Idle state and the
USB node is in the NodeSuspend state. The MIWU can be
programmed to generate an edge-triggered interrupt when
this occurs.
NodeOperational
This is the normal operating state of the node. In this state,
the node is configured for operation on the USB.
NodeSuspend
A USB node is expected to enter NodeSuspend state when
3 ms have elapsed without any detectable bus activity. The
USB node looks for this event and signals it by setting the
SD3 bit in the ALTEV register, which causes an interrupt, to
be generated (if enabled). Software should respond by put-
ting the USB node in the NodeSuspend state.
The USB node can resume normal operation under soft-
ware control in response to a local event in the device. It can
wake up the USB bus via a NodeResume, or when detect-
NodeOperational
NodeSuspend
NodeResume
NodeReset
State
Line Condition Detection
FUNCTIONAL STATES
Table 32 State Descriptions
Normal operation
Device operation suspend due to
USB inactivity
Device wake-up from suspended
state
Device reset
Descriptions
66
ing a resume command on the USB bus, which signals an
interrupt to the CPU.