Intel PXA26X - Manual (Page 438)

12-28 Intel® PXA26x Processor Family Developer’s Manual
Universal Serial Bus Device Controller
12.6.3.8 Transmit Short Packet (TSP)
The software uses the transmit short packet bit to indicate that the last byte of a data transfer to the
FIFO has occurred. This indicates to the UDC that a short packet or zero-sized packet is ready to
transmit. Software must not set this bit if a 64-byte packet is to be transmitted. When the data
packet is successful transmitted, the UDC clears this bit.
12.6.4 UDC Endpoint x Control/Status Register (UDCCSx), Where
x is 2, 7, or 12
The UDC endpoint x control/status register contains 7 bits that operate endpoint x, a Bulk OUT
endpoint.
Table 12-14. UDC Endpoint x Control Status Register, Where x is 1, 6 or 11
0h 4060 0014 UDCCS1 Read/Write
0h 4060 0028 UDCCS6 Read/Write
0h 4060 003C UDCCS11 Read/Write
Bit 31:8 7 6 5 4 3 2 1 0
Reserved TSP
Reserve
d
FST SST TUR FTF TPC TFS
Rese
t
X 0 0 0 0 0 0 0 1
Bits Name Description
0 TFS
TRANSMIT FIFO SERVICE (read-only):
0 – Transmit FIFO has no room for new data
1 – Transmit FIFO has room for at least 1 complete data packet
1 TPC
TRANSMIT PACKET COMPLETE (read/write 1 to clear):
0 – Error/status bits invalid.
1 – Transmit packet has been sent and error/status bits are valid.
2 FTF
FLUSH Tx FIFO (always read 0/ write a 1 to set):
1 – Flush Contents of TX FIFO
3 TUR
TRANSMIT FIFO UNDERRUN (read/write 1 to clear):
1 – Transmit FIFO experienced an underrun.
4 SST
SENT STALL (read/write 1 to clear):
1 – STALL handshake was sent.
5 FST
FORCE STALL (read/write):
1 – Issue STALL handshakes to IN tokens.
6 —
Reserved
Always reads 0
7 TSP
TRANSMIT SHORT PACKET (always read 0/write 1to set):
1 – Short packet ready for transmission.
31:8 — Reserved for future use