
SD Host Controller Programming Model
223
September 2005
SCPS110
12.15 Maximum Latency Register
The maximum latency register contains the maximum latency value for the SD host controller core.
Function 3 register offset: 3Fh
Register type:
Read/Update
Default value:
04h
BIT NUMBER
7
6
5
4
3
2
1
0
RESET STATE
0
1
0
Table 1210. Maximum Latency Register Description
BIT
FIELD NAME
TYPE
DESCRIPTION
70
MAX_LAT
RU
Maximum latency. The contents of this field may be used by host BIOS to assign an arbitration priority level
to the SD host controller. The default for this register indicates that the SD host controller may need to
access the PCI bus as often as every 0.25
s; thus, an extremely high priority level is requested. The
contents of this field may also be loaded through the serial EEPROM.
12.16 Slot Information Register
This read-only register contains information on the number of SD sockets implemented and the base address
registers used. The controller only implements one SD socket.
Function 3 register offset: 40h
Register type:
Read/Update
Default value:
00h
BIT NUMBER
7
6
5
4
3
2
1
0
RESET STATE
0
Table 1211. Maximum Latency Register Description
BIT
FIELD NAME
TYPE
DESCRIPTION
7
RSVD
R
Reserved. This bit returns 0b when read.
64
NUMBER_SLOTS
R
Number of slots. This field indicates the number of SD sockets supported by the SD host controller.
Since the controller supports one SD socket, this field returns 000b when read.
3
RSVD
R
Reserved. This bit returns 0b when read.
20
FIRST_BAR
R
First base address register number. This field is hardwired to 000b to indicate that the first BAR used
for the SD host standard registers is BAR0.
12.17 Capability ID and Next Item Pointer Registers
The capability ID and next item pointer register identifies the linked-list capability item and provides a pointer
to the next capability item. See Table 1212 for a complete description of the register contents.
Function 3 register offset: 80h
Register type:
Read-only
Default value:
0001h
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
1
Table 1212. Capability ID and Next Item Pointer Registers Description
BIT
FIELD NAME
TYPE
DESCRIPTION
158
NEXT_ITEM
R
Next item pointer. The SD host controller supports only one additional capability, PCI power
management, that is communicated to the system through the extended capabilities list; therefore,
this field returns 00h when read.
70
CAPABILITY_ID
R
Capability identification. This field returns 01h when read, which is the unique ID assigned by the PCI
SIG for PCI power-management capability.