ELANSC310 AMD [Advanced Micro Devices], ELANSC310 Datasheet - Page 35

• Manufacturer Part Number: ELANSC310
• Description: Single-Chip, 32-Bit, PC/AT Microcontroller
• Manufacturer: AMD [Advanced Micro Devices]

are asserted Low immediately after reset, and the
PMC3 signal is asserted High immediately after reset.
Each of the PMC pins can then be programmed to be
High or Low for each of the ÉlanSC310 microcontroller
power management modes.
SUS/RES
Suspend/Resume Operation (Input; Rising Edge)
When the ÉlanSC310 microcontroller is in High Speed
PLL, Low Speed PLL, or Doze mode, a positive edge
on this pin causes the internal logic to step down
through the Power Management modes (one per re-
fresh cycle) until Sleep mode is entered. If in Sleep,
Suspend, or Off mode, a positive edge on this pin
causes the ÉlanSC310 microcontroller to enter the
High Speed PLL mode.
MISCELLANEOUS INTERFACE
LF1, LF2, LF3, LF4 (Analog inputs)
Loop Filters
These pins are used to connect external components
that make up the loop filters for the internal PLLs. For
more information, see “Loop Filters” on page 86.
X1OUT [BAUD-OUT]
14-MHz/UART Output
This can be programmed to be either the 14.336-MHz
clock or the serial baud rate clock for serial infrared de-
vices. The 14.336-MHz output can be used by external
video controllers. As BAUD_OUT, it is 16 x the bit data
rate of the serial port and is used by serial infrared
devices.
X14OUT
14-MHz Output
The Parallel Port AFDT output can be programmed to
become X14OUT, a 14.336-MHz clock.
X32IN, X32OUT
32.768-kHz Crystal Interface
These pins are used for the 32.768-kHz crystal. This is
the main clock source for the ÉlanSC310 microcontrol-
ler and is used to drive the internal Phase-Locked
Loops that generate all other clock frequencies needed
in the system. For more information, see “Crystal Spec-
ifications” on page 84.
LOCAL BUS INTERFACE
The following list of pins is specific to local bus function-
ality. In Local Bus mode, additional ISA pins are also
available. These pins are described in the next section
“Maximum ISA Bus Interface” because these pins are
Élan™SC310 Microcontroller Data Sheet
P R E L I M I N A R Y
available in both Local Bus and Maximum ISA Bus
modes.
For more information, see “Maximum ISA Interface ver-
sus Local Bus Interface” on page 60, and Tables 33
and 34 on page 63.
ADS
Local Bus Address Strobe (Output; Active Low)
Local Bus Address Strobe is an active Low address
strobe signal for 386 local bus devices.
BHE
Local Bus Byte High Enable (Output; Active Low)
This signal indicates to the local bus devices that data
is being transferred on the high byte of the data bus.
BLE
Local Bus Byte Low Enable (Output; Active Low)
This signal indicates to the local bus devices that data
is being transferred on the low byte of the data bus.
CPUCLK (PULLUP)
CPU 2X Clock (Output)
This is the timing reference for the local bus device.
The high-speed PLL can be programmed to provide
one of the clock frequencies shown on page 44.
CPURDY
386 CPU Ready Signal (Output; Active Low)
This signal shows the current state of the 386 core
CPU’s CPURDY signal.
CPURST (RSVD)
CPU Reset (Output; Active High)
This signal is used to force the local bus device to an
initial condition. It is also used to allow the local bus de-
vice to synchronize to the CPUCLK. This signal is
taken directly from the internal CPU reset.
D/C
Local Bus Data/Control (Output; Active Low)
This signal indicates to the local bus devices that the
current cycle is either a Data cycle or a Control cycle.
A Low on this signal indicates that the current cycle is
a Control cycle.
LDEV (RSVD)
Local Bus Device Select (Input; Active Low)
This signal is used by the local bus devices to signal
that they will respond to the current cycle. If LDEV is
not driven active by the time required in Table 51 on
page 98, then the cycle defaults to an ISA bus cycle.
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