PCI4451 Datasheet, PDF (137/216 Pages) Texas Instruments – PC CARD AND OHCI CONTROLLER

6.5 Socket Control Register
This register provides control of the voltages applied to the socket’s V_PP and V_CC. The PCI4451 ensures that the
socket is powered up only at acceptable voltages when a CardBus card is inserted. See Table 6–6 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
Socket control
Type
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
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
Socket control
Type
R
R
R
R
R
R
R
R R/W R/W R/W R/W R R/W R/W R/W
Default 0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Register:
Type:
Offset:
Default:
Socket control
Read-only, Read/Write
CardBus Socket Address + 10h
0000 0000h
Table 6–6. Socket Control Register Description
BIT
SIGNAL
TYPE
FUNCTION
31–8
RSVD
R These bits return 0s when read.
This bit controls how the CardBus clock run state machine decides when to stop the CardBus clock to the
CardBus card:
0 = The PCI4451 clock run master will try to stop the clock to the CardBus card under the following two
conditions:
The CardBus interface is idle for 8 clocks and
There is a request from the PCI master to stop the PCI clock.
7
STOPCLK
R/W
1 = The PCI4451 clock run master will try to stop the clock to the CardBus card under the following
condition:
The CardBus interface is idle for 8 clocks.
In summary, if this bit is set to1, then the CardBus controller will try to stop the clock to the CardBus card
independent of the PCI clock run signal. The only condition that has to be satisfied in this case is the
CardBus interface sampled idle for 8 clocks.
6–4^† VCCCTRL
VCC control. These bits are used to request card VCC changes.
000 = Request power off (default)
001 = Reserved
010 = Request VCC = 5.0 V
R/W
011 = Request VCC = 3.3 V
100 = Request VCC = X.X V
101 = Request VCC = Y.Y V
110 = Reserved
111 = Reserved
3
RSVD
R This bit returns 0 when read.
VPP control. These bits are used to request card VPP changes.
2–0^†
VPPCTRL
R/W
000 = Request power off (default)
001 = Request VPP = 12.0 V
010 = Request VPP = 5.0 V
011 = Request VPP = 3.3 V
100 = Request VPP = X.X V
101 = Request VPP = Y.Y V
110 = Reserved
111 = Reserved
† _{This bit is cleared only by the assertion of GRST when PME is enabled. If PME is not enabled, then this bit is cleared by the assertion of PRST}
or GRST.
6–7