RM0082
HS_USB 2.0 device
Doc ID 018672 Rev 1
499/844
23.8.12 Endpoint
status
register
The endpoint status is a endpoint-specific RO register which reports the current status of
the associated endpoint. The Endpoint Status register bit assignments are given in
Note:
If the corresponding endpoint is bidirectional (both in and out), there will be two such
endpoint status registers.
[05:04]
ET
2’h0
Endpoint type.
This 2 bit field gives the endpoint type, according to
encoding:
– 2‘b00 = Control.
– 2‘b01 = Isochronous (ISO).
– 2‘b10 = Bulk.
– 2‘b11 = Interrupt.
[03]
P
1'h0
Poll demand.
If set, this bit indicates a poll demand from the application.
Note: This bit is reserved for out endpoints only.
[02]
SN
1'h0
Snoop mode.
Enabling this bit, the subsystem does not check the
correctness of out packets before transferring them to
application memory (snoop mode).
Note: This bit is reserved for in endpoints only.
[01]
F
1'h0
Flush the TxFIFO.
Setting this bit, it flushes the TxFIFO.
Note: This bit is reserved for out endpoints only.
[00]
S
1'h0
STALL handshake.
If set, this bit forces the endpoint to reply to the USB Host
with a STALL handshake. For example, on successful
reception of a SETUP packet (preliminarily decoded by the
application), the subsystem clears both in and out stall bits,
and sets both in and out NAK bits. In case of non-SETUP
packets, the subsystem clears either in or out stall bit if a
STALL handshake is sent back to the USB Host, and set the
corresponding NAK bit. Besides, a STALL handshake for
next transactions of a stalled endpoint is returned until the
USB Host issues a Clear_Feature command to clear it.
Note: The application must check for RxFIFO emptiness
before setting the in and out stall bit.
Table 407.
Endpoint control register bit assignments (continued)
Bit
Name
Reset value Description