USB Device Controller

12.6.4.8Transmit 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.

These are read/write registers. Ignore reads from reserved bits. Write zeros to reserved bits.

12.6.5UDC Endpoint x Control/Status Register (UDCCS2/7/12)

UDCCS2/7/12, shown in Table 12-16, contains 7 bits that are used to operate endpoint x, a Bulk OUT endpoint.

Table 12-16. UDCCS2/7/12 Bit Definitions

 

 

 

 

 

0x 4060_0018

 

 

 

 

 

 

UDCCS2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0x 4060_002C

 

 

 

 

 

 

UDCCS7

 

 

 

 

 

USB Device Controller

 

 

 

 

 

 

 

0x 4060_0040

 

 

 

 

 

 

UDCCS12

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

reserved

 

RSP

RNE FST

SST

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

x

x

x

x x

x

x

x x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x 0 0 0 0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bit

 

Name

 

 

 

 

 

 

 

 

 

 

Description

 

 

 

 

31:8

 

reserved

 

 

 

 

7

 

RSP

Receive short packet (read-only).

 

 

 

 

 

1 = Short packet received and ready for reading.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Receive FIFO not empty (read-only).

 

 

 

 

6

 

RNE

0 = Receive FIFO empty.

 

 

 

 

 

 

 

 

 

 

1 = Receive FIFO not empty.

 

 

 

 

5

 

FST

Force stall (read/write).

 

 

 

 

 

1 = Issue STALL handshakes to OUT tokens.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4

 

SST

Sent stall (read/write 1 to clear).

 

 

 

 

 

1 = STALL handshake was sent.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DMA Enable(read/write)

 

 

 

 

3

 

DME

0 = Send data received interrupt after EOP received

 

 

 

 

 

1 = Send data received interrupt after EOP received and Receive FIFO has

 

 

 

 

 

 

 

 

 

 

 

 

 

data

 

 

 

 

2

 

reserved

 

 

 

 

Receive packet complete (read/write 1 to clear).

1

RPC

0 =

Error/status bits invalid.

 

 

1 =

Receive packet has been received and error/status bits are valid.

Receive FIFO service (read-only).

0

RFS

0 =

Receive FIFO has less than 1 data packet.

 

 

1 =

Receive FIFO has 1 or more data packets.

DME reserved RPC RFS

0 0 0 0

< 32 bytes of

Intel® PXA255 Processor Developer’s Manual

12-29

Page 431
Image 431
Intel PXA255 UDC Endpoint x Control/Status Register UDCCS2/7/12, Transmit Short Packet TSP, UDCCS2/7/12 Bit Definitions