F I N A L
BLOCK DIAGRAM
Segmentation Unit
Effective Address Bus
Paging Unit
Adder
25
Page
Cache
Control
and
Attribute
PLA
Code Fetch/Page Table Fetch
Linear Address Bus
Physical Address Bus
Bus Control
Request
Prioritizer
Control
3-Input
Adder
32
Descriptor
Registers
Limit and
Attribute
PLA
32
Effective Address Bus
HOLD, INTR,
NMI, ERROR,
BUSY, RESET,
HLDA, FLT,
SMI*, IIBEN*
32
Protection
Test Unit
Displacement Bus
Address
Driver
Pipeline/
Bus Size
Control
MUX/
Trans-
ceivers
BHE, BLE,
A23-A1
M/IO, D/C,
W/R, LOCK,
ADS, NA,
READY,
SMIADS*,
SMIRDY*
D15-D0
Internal Control Bus
Barrel
Shifter,
Adder
Multiply/
Divide
Register
File
Status
Flags
Decode
and
Sequencing
Instruction
Decoder
Code
Stream
Prefetcher/
Limit
Checker
16-Byte
Code
Queue
Instruction
Prefetch
32
ALU
Control
Control
ROM
Control
3-Decoded
Instruction
Queue
Instruction
Predecode
Dedicated ALU Bus
32 Bit
ALU
* – On Am386SXLV only
32
FUNCTIONAL DESCRIPTION
True Static Operation
(Am386SXL/SXLV Only)
The Am386SXL/SXLV microprocessor incorporates a
true static design. Unlike dynamic circuit design, the
Am386SXL/SXLV device eliminates the minimum op-
erating frequency restriction. It may be clocked from its
maximum speed all the way down to 0 MHz (DC). Sys-
tem designers can use this feature to design portable
applications with long battery life.
plifies the design of power-conscious portable applica-
tions in the following ways.
s
Eliminates the need for software in BIOS to save
and restore the contents of registers.
s
Allows simpler circuitry to control stopping of the
clock since the system does not need to know
the state of the processor.
Standby Mode (Am386SXL/SXLV Only)
The true static design of the Am386SXL/SXLV micro-
processor allows for a Standby Mode. At any operating
speed, the microprocessor will retain its state (i.e., the
contents of all its registers). By shutting off the clock
completely, the device enters Standby Mode. Since
power consumption is proportional to clock frequency,
operating power consumption is reduced as the fre-
quency is lowered. In Standby Mode, typical current
draw is reduced to less than 20 microamps at DC. Not
only does this feature save battery life, but it also sim-
Lower Operating Icc
(Am386SXL/SXLV Only)
True static design also allows lower operating Icc when
operating at any speed.
Performance on Demand
(Am386SXL/SXLV Only)
The Am386SXL/SXLV microprocessor retains its state
at any speed from 0 MHz (DC) to its maximum operat-
ing speed. With this feature, system designers may
vary the operating speed of the system to extend the
battery life in portable systems.
Am386SX/SXL/SXLV Microprocessors Data Sheet
3
AMD [ ADVANCED MICRO DEVICES ]
