Revision 1.02 – June 27, 2006
S5935 – PCI Product
Data Book
Table 39. PC Compatible Expansion ROM
Byte Offset Byte Length
Binary Value
Description
Example
68h
70h
74h
7Ch
7Dh
7Eh
7Fh
8
4
8
1
1
1
1
not used
[Expansion ROM base addr.] (example shows 32K bytes)
FFFF8001h
not used
[Interrupt line]
[Interrupt pin]
[Min-Grant]
[Max_lat]
0Ch
01h
00h
00h
80h —
application specific
(1FFh), or
(2FFh), or
(3FFh), etc.
Byte checksum, location dependent on value for length field at offset 0002h.
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 3 and
contains various vendor, product, and program evolu-
tions. If a valid external nv memory is identified by the
S5935, the PCI data structure is used to configure the
S5935. The PCI data structure is not necessary for this
device to operate. If no external nv memory is imple-
mented, the S5935 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.
Table 40. PCI Data Structure
Byte
Binary
Value
Byte Offset Length
Description
0h
4
2
2
2
2
1
3
2
2
1
1
2
‘PCIR’
var.
Signature, the ASCII string ‘PCIR’ where ‘P’ is at offset 0, ‘C’ at offset 1, and so on.
4h
Vendor Identification
6h
var.
Device Identification
8h
var.
Pointer to Vital Product Data
PCI Data Structure Length (starts with signature field)
PCI Data Structure Revision (=0 for this definition)
Class Code
Ah
var.
Ch
Dh
10h
12h
14h
15h
16h
var.
var.
var.
Image Length
var.
Revision Level
var.
Code Type
var.
Indicator (bit D7=1 signifies “last image”)
Reserved
0000h
98
DS1527
AMCC Confidential and Proprietary
AMCC [ APPLIED MICRO CIRCUITS CORPORATION ]
