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Revision 1.1
G
Signal Definitions
(Continued)
2.4
Information in the tables that follow may have duplicate information in multiple tables. Multiple references all contain identi-
cal information.
SIGNAL DESCRIPTIONS
2.4.1
System Interface
Signal Name
Ball No.
Type
Description
Mux
CLKSEL1
AD25
I
Fast-PCI Clock Selects.
These strap signals are used to
set the internal Fast-PCI clock.
00 = 33.3 MHz
01 = Reserved
10 = 66.7 MHz
11 = 33.3 MHz
During system reset, an internal pull-down resistor of 100
K
exists on these balls. An external pull-up or pull-down
resistor of 1.5 K
must be used.
GNT1#
CLKSEL0
D23
RD#
CLKSEL3
AE22
I
Maximum Core Clock Multiplier.
These strap signals
are used to set the maximum allowed multiplier value for
the core clock.
During system reset, an internal pull-down resistor of 100
K
exists on these balls. An external pull-up or pull-down
resistor of 1.5 K
must be used.
SYNC
CLKSEL2
AD22
SDATA_OUT
BOOT16
C23
I
Boot ROM is 16 Bits Wide.
This strap signal enables
the optional 16-bit wide Sub-ISA bus.
During system reset, an internal pull-down resistor of 100
K
exists on these balls. An external pull-up or pull-down
resistor of 1.5 K
must be used.
ROMCS#
LPC_ROM
AB26
I
LPC_ROM.
If pulled high during reset, this strap signal
forces selection of the LPC bus and sets bit F0BAR1+I/O
Offset 10h[15], LPC ROM Addressing Enable. It enables
the SC1100 to boot from a ROM connected to the LPC
bus.
During system reset, an internal pull-down resistor of 100
K
exists on these balls. An external pull-up or pull-down
resistor of 1.5 K
must be used.
GNT0#
FPCI_MON
AB25
I
Fast-PCI Monitoring.
The strap on this ball forces selec-
tion of Fast-PCI monitoring signals. For normal operation,
strap this signal low using a 1.5 K
resistor. The value of
this strap can be read on the MCR[30].
PCICLKO
POR#
AE21
I
Power On Reset.
POR# is the system reset signal gen-
erated from the power supply to indicate that the system
should be reset.
---
X32I
W1
I
Crystal Connections.
Connected directly to a 32.768
KHz crystal. This clock input is required even if the inter-
nal RTC is not being used. Some of the internal clocks
are derived from this clock. If an external clock is used, it
should be connected to X32I, using a voltage level of 0V
to V
CORE
+10% maximum. X32O should remain uncon-
nected.
---
X32O
W2
O
---
X27I
AF10
I
Crystal Connections.
Connected directly to a 27.000
MHz crystal. Some of the internal clocks are derived from
this clock. If an external clock is used, it should be con-
nected to X27I, using a voltage level of 0V to V
IO
and
X27O should be remain unconnected.
---
X27O
AE10
O
---