1394 OHCI Memory-Mapped TI Extension Register Space
166
March 5 2007 June 2011
SCPS154C
9.2
Isochronous Receive Digital Video Enhancements
The DV frame sync and branch enhancement provides a mechanism in buffer-fill mode to synchronize 1394
DV data that is received in the correct order to DV frame-sized data buffers described by several
INPUT_MORE descriptors (see 1394 Open Host Controller Interface Specification, Release 1.1). This is
accomplished by waiting for the start-of-frame packet in a DV stream before transferring the received
isochronous stream into the memory buffer described by the INPUT_MORE descriptors. This can improve
the DV capture application performance by reducing the amount of processing overhead required to strip the
CIP header and copy the received packets into frame-sized buffers.
The start of a DV frame is represented in the 1394 packet as a 16-bit pattern of 1FX7h (first byte 1Fh and
second byte X7h) received as the first two bytes of the third quadlet in a DV isochronous packet.
9.3
Isochronous Receive Digital Video Enhancements Register
The isochronous receive digital video enhancements register enables the DV enhancements in the controller.
The bits in this register may only be modified when both the active (bit 10) and run (bit 15) bits of the
corresponding context control register are 00b. See
Table 92 for a complete description of the register
contents.
TI extension register offset: A80h
set register
A84h
clear register
Register type:
Read/Set/Clear, Read-only
Default value:
0000 0000h
BIT NUMBER
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RESET STATE
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
Table 92. Isochronous Receive Digital Video Enhancements Register Description
BIT
FIELD NAME
TYPE
DESCRIPTION
3114
RSVD
R
Reserved. Bits 3114 return 00 0000 0000 0000 0000b when read.
13
DV_Branch3
RSC
When bit 13 is set to 1b, the isochronous receive context 3 synchronizes reception to the DV frame
start tag in bufferfill mode if input_more.b = 01b, and jumps to the descriptor pointed to by frameBranch
if a DV frame start tag is received out of place. This bit is only interpreted when bit 12 (CIP_Strip3) is
set to 1b and bit 30 (isochHeader) in the isochronous receive context control register at OHCI offset
460h/464h (see Section
8.44) is cleared to 0b.
12
CIP_Strip3
RSC
When bit 12 is set to 1b, the isochronous receive context 3 strips the first two quadlets of payload. This
bit is only interpreted when bit 30 (isochHeader) in the isochronous receive context control register at
OHCI offset 460h/464h (see Section
8.44) is cleared to 0b.
1110
RSVD
R
Reserved. Bits 11 and 10 return 00b when read.
9
DV_Branch2
RSC
When bit 9 is set to 1b, the isochronous receive context 2 synchronizes reception to the DV frame start
tag in bufferfill mode if input_more.b = 01b, and jumps to the descriptor pointed to by frameBranch if
a DV frame start tag is received out of place. This bit is only interpreted when bit 8 (CIP_Strip2) is set
to 1b and bit 30 (isochHeader) in the isochronous receive context control register at OHCI offset
440h/444h (see Section
8.44) is cleared to 0b.
8
CIP_Strip2
RSC
When bit 8 is set to 1b, the isochronous receive context 2 strips the first two quadlets of payload. This
bit is only interpreted when bit 30 (isochHeader) in the isochronous receive context control register at
OHCI offset 440h/444h (see Section
8.44) is cleared to 0b.
76
RSVD
R
Reserved. Bits 7 and 6 return 00b when read.
Not Recommended for New Designs