7 configuration rom header register, 8 bus identification register – Texas Instruments TSB12LV26 User Manual
Page 46
4–8
4.7
Configuration ROM Header Register
The configuration ROM header register externally maps to the first quadlet of the 1394 configuration ROM, offset
FFFF F000 0400h. See Table 4–6 for a complete description of the register contents.
Bit
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Name
Configuration ROM header
Type
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Default
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Bit
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Name
Configuration ROM header
Type
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Default
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Register:
Configuration ROM header
Type:
Read/Write
Offset:
18h
Default:
0000 XXXXh
Table 4–6. Configuration ROM Header Register Description
BIT
FIELD NAME
TYPE
DESCRIPTION
31–24
info_length
R/W
IEEE 1394 bus management field. Must be valid when bit 17 (linkEnable) of the host controller control
register (OHCI offset 50h/54h, see Section 4.16) is set.
23–16
crc_length
R/W
IEEE 1394 bus management field. Must be valid when bit 17 (linkEnable) of the host controller control
register (OHCI offset 50h/54h, see Section 4.16) is set.
15–0
rom_crc_value
R/W
IEEE 1394 bus management field. Must be valid at any time bit 17 (linkEnable) of the host controller
control register (OHCI offset 50h/54h, see Section 4.16) is set. The reset value is undefined if no serial
ROM is present. If a serial ROM is present, then this field is loaded from the serial ROM.
4.8
Bus Identification Register
The bus identification register externally maps to the first quadlet in the Bus_Info_Block, and contains the constant
3133 3934h, which is the ASCII value of 1394.
Bit
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Name
Bus identification
Type
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
Default
0
0
1
1
0
0
0
1
0
0
1
1
0
0
1
1
Bit
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Name
Bus identification
Type
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
Default
0
0
1
1
1
0
0
1
0
0
1
1
0
1
0
0
Register:
Bus identification
Type:
Read-only
Offset:
1Ch
Default:
3133 3934h