4.29 System Control Register
System-level initializations are performed through programming this doubleword register. Some of the bits are global
in nature and must be accessed only through function 0. See Table 4−8 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
Type
Default
System control
RW
0
RW
0
RW
0
RW
0
RW
1
RW
0
RW
0
RW
0
R
0
RW
1
RW
0
RW
0
R
0
R
0
R
0
R
0
Bit
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Name
Type
Default
System control
RW
1
RW
0
R
0
R
1
R
0
R
0
R
0
R
0
R
0
RW
1
RW
1
RW
0
RW
0
R
0
RW
0
RW
0
Register:
Offset:
Type:
System control
80h (Functions 0, 1)
Read-only, Read/Write
0840 9060h
Default:
Table 4−8. System Control Register Description
BIT
SIGNAL
TYPE
FUNCTION
Serial input stepping. In serial PCI interrupt mode, these bits are used to configure the serial stream PCI
interrupt frames, and can be used to accomplish an even distribution of interrupts signaled on the four PCI
interrupt slots.
00 = INTA/INTB/INTC/INTD signal in INTA/INTB/INTC/INTD slots (default)
01 = INTA/INTB/INTC/INTD signal in INTB/INTC/INTD/INTA slots
10 = INTA/INTB/INTC/INTD signal in INTC/INTD/INTA/INTB slots
11 = INTA/INTB/INTC/INTD signal in INTD/INTA/INTB/INTC slots
31−30 ‡§ SER_STEP
RW
This bit ties INTA to INTB internally (to INTA), and reports this through the interrupt pin register (PCI offset
3Dh, see Section 4.24). This bit has no effect on INTC or INTD.
29 ‡§
28 ‡
INTRTIE
TIEALL
RW
RW
This bit ties INTA, INTB, INTC, and INTD internally (to INTA), and reports this through the interrupt pin
register (PCI offset 3Dh, see Section 4.24).
P2C power switch clock. The PCI6x21/PCI6x11 CLOCK signal clocks the serial interface power switch
and the internal state machine. The default state for this bit is 0, requiring an external clock source provided
to the CLOCK terminal. Bit 27 can be set to 1, allowing the internal oscillator to provide the clock signal.
0 = CLOCK is provided externally, input to the PCI6x21/PCI6x11 controller.
1 = CLOCK is generated by the internal oscillator and driven by the PCI6x21/PCI6x11 controller.
(default)
27 ‡
PSCCLK
RW
SMI interrupt routing. This bit is shared between functions 0 and 1, and selects whether IRQ2 or CSC is
signaled when a write occurs to power a PC Card socket.
26 ‡§
25 ‡
SMIROUTE
SMISTATUS
RW
RW
0 = PC Card power change interrupts are routed to IRQ2 (default).
1 = A CSC interrupt is generated on PC Card power changes.
SMI interrupt status. This socket-dependent bit is set when a write occurs to set the socket power, and
the SMIENB bit is set. Writing a 1 to this bit clears the status.
0 = SMI interrupt is signaled.
1 = SMI interrupt is not signaled.
SMI interrupt mode enable. When this bit is set, the SMI interrupt signaling generates an interrupt when
a write to the socket power control occurs. This bit is shared and defaults to 0 (disabled).
0 = SMI interrupt mode is disabled (default).
24 ‡§
23
SMIENB
RSVD
RW
R
1 = SMI interrupt mode is enabled.
Reserved
‡
§
One or more bits in this register are cleared only by the assertion of GRST.
These bits are global in nature and must be accessed only through function 0.
4−18
TI [ TEXAS INSTRUMENTS ]
