NUC970 Technical Reference Manual
Publication Release Date: Dec. 15, 2015
- 707 -
Revision V1.30
NUC97
0
T
E
CHNIC
A
L
RE
F
E
RE
N
CE
MA
NUA
L
[7]
DISBUF
Buffer Disable Control
This bit is used to receive unknown size OUT short packet. The received packet size is
reference USBD_EPxDATCNT register.
0 = Buffer Not Disabled when Bulk-OUT short packet is received.
1 = Buffer Disabled when Bulk-OUT short packet is received.
[6]
SHORTTXEN
Short Packet Transfer Enable
This bit is applicable only in case of Auto-Validate Method. This bit is set to validate
any remaining data in the buffer which is not equal to the MPS of the endpoint, and
happens to be the last transfer. This bit gets cleared once the data packet is sent.
0 = Not validate any remaining data in the buffer which is not equal to the MPS of the
endpoint.
1 = Validate any remaining data in the buffer which is not equal to the MPS of the
endpoint.
[5]
ZEROLEN
Zero Length
This bit is used to send a zero-length packet response to an IN-token. When this bit is
set, a zero packet is sent to the host on reception of an IN-token. This bit gets cleared
once the zero length data packet is sent.
0 = A zero packet is not sent to the host on reception of an IN-token.
1 = A zero packet is sent to the host on reception of an IN-token.
[4]
HALT
Endpoint Halt
This bit is used to send a STALL handshake as response to the token from the host.
When an Endpoint Set Feature (ep_halt) is detected by the local CPU, it must write a
‘1’ to this bit.
0 = Not send a STALL handshake as response to the token from the host.
1 = Send a STALL handshake as response to the token from the host.
[3]
TOGGLE
Endpoint Toggle
This bit is used to clear the endpoint data toggle bit. Reading this bit returns the current
state of the endpoint data toggle bit.
The local CPU may use this bit to initialize the end-
point’s toggle in case of reception
of a Set Interface request or a Clear Feature (ep_halt) request from the host. Only
when toggle bit is “1”, this bit can be written into the inversed write data bit[3].
0 = Not clear the endpoint data toggle bit.
1 = Clear the endpoint data toggle bit.
[2:1]
MODE
Mode Control
The two bits decide the operation mode of the in-endpoint.
00: Auto-Validate Mode
01: Manual-Validate Mode
10: Fly Mode
11: Reserved
These bits are not valid for an out-endpoint. The auto validate mode will be activated
when the reserved mode is selected.
[0]
FLUSH
Buffer Flush
Writing 1 to this bit causes the packet buffer to be flushed and the corresponding
EP_AVAIL register to be cleared. This bit is self-clearing. This bit should always be
written after an configuration event.
0 = The packet buffer is not flushed.
1 = The packet buffer is flushed by user.