9 latency timer register, 10 header type register, 11 bist register – Texas Instruments Dual/Single Socket CardBus and UntraMedia Controller PCI7621 User Manual
Page 97
4−7
4.9
Latency Timer Register
The latency timer register specifies the latency timer for the PCI7x21/PCI7x11 controller, in units of PCI clock cycles.
When the PCI7x21/PCI7x11 controller is a PCI bus initiator and asserts FRAME, the latency timer begins counting
from zero. If the latency timer expires before the PCI7x21/PCI7x11 transaction has terminated, then the
PCI7x21/PCI7x11 controller terminates the transaction when its GNT is deasserted.
Bit
7
6
5
4
3
2
1
0
Name
Latency timer
Type
RW
RW
RW
RW
RW
RW
RW
RW
Default
0
0
0
0
0
0
0
0
Register:
Latency timer
Offset:
0Dh
Type:
Read/Write
Default: 00h
4.10 Header Type Register
The header type register returns 82h when read, indicating that the PCI7x21/PCI7x11 functions 0 and 1 configuration
spaces adhere to the CardBus bridge PCI header. The CardBus bridge PCI header ranges from PCI registers
00h−7Fh, and 80h−FFh is user-definable extension registers.
Bit
7
6
5
4
3
2
1
0
Name
Header type
Type
R
R
R
R
R
R
R
R
Default
1
0
0
0
0
0
1
0
Register:
Header type
Offset:
0Eh (Functions 0, 1)
Type:
Read-only
Default: 82h
4.11 BIST Register
Because the PCI7x21/PCI7x11 controller does not support a built-in self-test (BIST), this register returns the value
of 00h when read.
Bit
7
6
5
4
3
2
1
0
Name
BIST
Type
R
R
R
R
R
R
R
R
Default
0
0
0
0
0
0
0
0
Register:
BIST
Offset:
0Fh (Functions 0, 1)
Type:
Read-only
Default: 00h