
S5335 – PCI Bus Controller, 3.3V
Revision 5.01 – November 30, 2005
Data Sheet
AMCC Confidential and Proprietary
DS1657 91
A 16-bit pointer at location 18h of the PC expansion
ROM identifies the start offset of the PCI data struc-
ture. The PCI data structure is shown in Table 53 and
contains various vendor, product, and program evolu-
tions. If a valid external nv memory is identified by the
S5335, the PCI data structure is used to configure the
S5335. The PCI data structure is not necessary for this
device to operate. If no external nv memory is imple-
mented, the S5335 boots with the default configuration
values.
Note: If a serial BIOS ROM is used, the access time
for large serial devices should be considered, since it
may cause a lengthy system delay during initialization.
For example, a 2-Kbyte serial device takes about 1
second to be read. Many systems, even when BIOS
ROMs are ultimately shadowed into system RAM, may
read this memory space twice (once to validate its size
and checksum, and once to move it into RAM). Execu-
tion directly from a serial BIOS ROM, although
possible, may be unacceptably slow.
68h
70h
74h
7Ch
7Dh
7Eh
7Fh
8
4
8
1
1
1
1
not used
[Expansion ROM base addr.]
not used
[Interrupt line]
[Interrupt pin]
[Min-Grant]
[Max_lat]
(example shows 32K bytes)
FFFF8001h
0Ch
01h
00h
00h
80h —
(1FFh), or
(2FFh), or
(3FFh), etc.
application specific
Byte checksum, location dependent on value for length field at offset 0002h.
Table 52. PC Compatible Expansion ROM (Continued)
Byte Offset
Byte Length
Binary Value
Description
Example
Table 53. PCI Data Structure
Byte Offset
Byte
Length
Binary
Value
Description
0h
4h
6h
8h
Ah
Ch
Dh
10h
12h
14h
15h
16h
4
2
2
2
2
1
3
2
2
1
1
2
‘PCIR’
var.
var.
var.
var.
var.
var.
var.
var.
var.
var.
0000h
Signature, the ASCII string ‘PCIR’ where ‘P’ is at offset 0, ‘C’ at offset 1, and so on.
Vendor Identification
Device Identification
Pointer to Vital Product Data
PCI Data Structure Length (starts with signature field)
PCI Data Structure Revision (=0 for this definition)
Class Code
Image Length
Revision Level
Code Type
Indicator (bit D7=1 signifies “l(fā)ast image”)
Reserved