Datasheet
6−8
6.5 Socket Control Register
The socket control register provides control of the voltages applied to the socket and instructions for the CB CLKRUN
protocol. The PCI1520 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 RW R RW RW RW RW R RW RW RW
Default 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0
Register: Socket control
Offset: CardBus socket address + 10h
Type: Read-only, Read/Write
Default: 0000 0400h
Table 6−6. Socket Control Register Description
BIT SIGNAL TYPE FUNCTION
31−12 RSVD R Reserved. These bits return 0 when read. A write to these bits has no effect.
11 ZV_ACTIVITY R
Zoomed video activity. This bit returns 0 when the ZVEN bits for both sockets are 0 (disabled). If either
ZVEN bit is set to 1, the ZV_ACTIVITY bit returns 1.
10 STDZVREG R
Standardized zoomed video register model support. This bit returns 1 by default when the STDZVEN
bit (bit 0) in the diagnostic register is cleared (PCI offset 93h, see Section 4.34).
9 ZVEN RW Zoomed video enable. This bit enables zoomed video for this socket.
8 RSVD R Reserved. ThIs bit returns 0 when read. A write to thIs bit has no effect.
7 STOPCLK RW
CB CLKRUN protocol instructions.
0 = CB CLKRUN
protocol can only attempt to stop/slow the CB clock if the socket is idle and the
PCI CLKRUN
protocol is preparing to stop/slow the PCI bus clock.
1 = CB CLKRUN
protocol can attempt to stop/slow the CB clock if the socket is idle.
6−4 VCCCTRL RW
V
CC
control. Bits 6−4 request card V
CC
changes.
000 = Request power off (default) 100 = Request V
CC
= X.X V
001 = Reserved 101 = Request V
CC
= Y.Y V
010 = Request V
CC
= 5 V 110 = Reserved
011 = Request V
CC
= 3.3 V 111 = Reserved
3 RSVD R Reserved. Bit 3 returns 0 when read.
2−0 VPPCTRL RW
V
PP
control. Bits 2−0 request card V
PP
changes.
000 = Request power off (default) 100 = Request V
PP
= X.X V
001 = Request V
PP
= 12 V 101 = Request V
PP
= Y.Y V
010 = Request V
PP
= 5 V 110 = Reserved
011 = Request V
PP
= 3.3 V 111 = Reserved