Electronic Components Datasheet Search
  English  ▼
ALLDATASHEET.NET

X  

NS486SXL Datasheet(PDF) 4 Page - National Semiconductor (TI)

[Old version datasheet] Texas Instruments acquired National semiconductor.
Part # NS486SXL
Description  Optimized 32-Bit 486-Class Controller with On-Chip Peripherals for Embedded Systems
Download  6 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  NSC [National Semiconductor (TI)]
Direct Link  http://www.national.com
Logo NSC - National Semiconductor (TI)

NS486SXL Datasheet(HTML) 4 Page - National Semiconductor (TI)

  NS486SXL Datasheet HTML 1Page - National Semiconductor (TI) NS486SXL Datasheet HTML 2Page - National Semiconductor (TI) NS486SXL Datasheet HTML 3Page - National Semiconductor (TI) NS486SXL Datasheet HTML 4Page - National Semiconductor (TI) NS486SXL Datasheet HTML 5Page - National Semiconductor (TI) NS486SXL Datasheet HTML 6Page - National Semiconductor (TI)  
Zoom Inzoom in Zoom Outzoom out
 4 / 6 page
background image
1.0 System Overview (Continued)
Certain I/O lines not being used by disabled peripherals can
be reconfigured for use as general purpose bidirectional I/O
lines (up to 28 pins). This gives the designer maximum flex-
ibility in designing various systems using the NS486SXL de-
vice. It is expected that an NS486SXL system will minimally
include the NS486SXL system controller with on-board pro-
cessor and I/O devices, boot ROM, and working RAM
memory. Many applications will not require any additional I/O
support.
Finally, the NS486SXL implements a very flexible power
management scheme that permits selective control of indi-
vidual I/O subsystems, with varying levels of power con-
sumption.
NS486SXL provides a cost-effective hardware platform for
the design and implementation of a wide range of internet
appliance, networking and communication systems. With its
powerful embedded ’486-class processor, comprehensive
set of on-chip peripheral controllers, flexible power manage-
ment structure and reconfigurable I/O lines, NS486SXL
makes possible a variety of end-user systems based on the
same hardware. Because of its optimized design and on-
board resources, a very cost effective system can be
achieved.
1.2 32-BIT PROCESSOR CORE
The NS486SXL processor core is an implementation of the
protected mode ’486 instruction set architecture, optimized
using a RISC-like design philosophy for embedded applica-
tions. Using this approach, the most frequently used instruc-
tions are optimized, and on an average execute in a lower
number of clock cycles than a ’486.
The NS486SXL features a three stage pipeline, efficient in-
struction prefetching mechanism, and single cycle instruc-
tion decoding for most instructions. Additionally, a 1 Kbyte in-
struction cache and single cycle DRAM access provide
higher memory performance than a larger unified cache
implementation.
The NS486SXL processor provides the same programming
model and register set as the standard ’486 except that real
mode, virtual memory, and floating point support have been
eliminated. These features have little or no impact in embed-
ded applications and save significant silicon real estate. At
reset, unlike the standard ’486, the NS486SXL starts up in
protected mode instead of real mode. All ’486 instructions
appropriate to protected mode and our hardware configura-
tion are supported, including debug instructions.
The NS486SXL is initially available to run 25 MHz at 5V. The
processor clock is obtained by dividing the crystal frequency
by two. For example, a 25 MHz NS486SXL runs with a
50 MHz crystal oscillator as the master clock.
As a result of our innovative design, the NS486SXL achieves
performance equivalent to a standard ’486 with less circuitry.
This translates into reduced power consumption and a lower
overall system cost. It also makes the NS486SXL ideal for
“green” systems and battery operated systems.
1.3 SYSTEM SERVICE ELEMENTS
The NS486SXL controller provides the basic hardware re-
sources required for the O/S-defined System Service Ele-
ments. These include a DRAM controller, programmable in-
terval timer, a protected WATCHDOG timer, a programmable
interrupt controller, a real-time clock and calendar, and com-
prehensive power management features.
1.3.1 DRAM Controller
The NS486SXL DRAM controller supports one or two
adjustable-sized banks of dynamic RAM using a 16-bit data
path. Support is provided for byte parity (if desired), requiring
the DRAM banks to be 18-bits wide when parity is enabled.
Banks can be up to 8 Mbytes in size. The DRAM controller
supports page mode read and write operations and can also
support both byte and word accesses. All access control sig-
nals for read, write and parity checking are generated as well
as an automatic and programmable CAS-before-RAS re-
fresh. If self-refresh DRAMs are used, refresh can be dis-
abled, saving power.
NS486SXL provides flexible support for use of a number of
different DRAM configurations, using popular DRAM de-
vices. Access is optimized for fast page mode DRAMs, and
they will provide the highest performance with contiguous
data. When accessing data bytes or words in the same
DRAM page, the data access is in one cycle. This perfor-
mance provides fast data access times without the overhead
of a separate data cache. Page sizes can be 512, 1024,
2048 or 4096 bytes. Flexibility for DRAM timing is provided
through programming of the DRAM controller registers: 3 or
4 cycle page miss accesses and extended CAS cycles can
be selected.
Memory bank 0 starts at address 0h; memory bank 1 can
start at any address in the 128 Mbyte address map that is a
multiple of its size.
1.3.2 Programmable Interval Timer
The NS486SXL programmable interval timer is compatible
with the Intel 8254 programmable interval timer and contains
three identical timers (CH0–CH2). CH0 and CH1 can be
used to generate accurate timing delays under software con-
trol. CH2 may be configured to provide a WATCHDOG timer
function.
1.3.3 WATCHDOG Timer
The NS486SXL WATCHDOG timer, CH2, is a protected 16-
bit timer that can be used to prevent system “lockups or
hangups.” It uses a 1 kHz clock generated by the on-chip
real-time clock circuit. If the WATCHDOG timer is enabled
and times out, a reset or interrupt will be generated allowing
graceful recovery from an unexpected system lockup.
1.3.4 Interrupt Controller
The NS486SXL interrupt controller consists of two cascaded
programmable interrupt controllers that are compatible with
the Intel 8259A Programmable Interrupt Controller. They pro-
vide a total of 15 (out of 16) programmable interrupts. Three
interrupts are reserved for a real time clock-tick interrupt, a
real time clock interrupt request, and a cascade interrupt
channel. The remaining 13 interrupts can be used by internal
or external sources. Additional external interrupt controllers
can be cascaded as well.
1.3.5 Real Time Clock/Calendar
The NS486SXL Real Time Clock/Calendar is a low power
clock that provides a time-of-day clock and 100-year calen-
dar with alarm features and battery operation. Time is kept in
BCD or binary format. It includes 50 bytes of general pur-
pose CMOS RAM and 3 maskable interrupt sources. It is
compatible with the DS1287 and MC146818 RTC/Calendar
devices, except for the general purpose memory size.
www.national.com
4


Similar Part No. - NS486SXL

ManufacturerPart #DatasheetDescription
logo
National Semiconductor ...
NS486SXF NSC-NS486SXF Datasheet
444Kb / 44P
   NS486TMSXF Optimized 32-Bit 486-Class Controller with On-Chip Peripherals for Embedded Systems
logo
Texas Instruments
NS486SXF TI1-NS486SXF Datasheet
482Kb / 46P
[Old version datasheet]   Optimized 32-Bit 486-Class Controller
NS486SXF-25/NOPB TI1-NS486SXF-25/NOPB Datasheet
482Kb / 46P
[Old version datasheet]   Optimized 32-Bit 486-Class Controller
More results

Similar Description - NS486SXL

ManufacturerPart #DatasheetDescription
logo
National Semiconductor ...
NS486SXF NSC-NS486SXF Datasheet
444Kb / 44P
   NS486TMSXF Optimized 32-Bit 486-Class Controller with On-Chip Peripherals for Embedded Systems
logo
Texas Instruments
NS486SXF TI1-NS486SXF Datasheet
482Kb / 46P
[Old version datasheet]   Optimized 32-Bit 486-Class Controller
logo
Fujitsu Component Limit...
MB86831 FUJITSU-MB86831 Datasheet
1Mb / 82P
   32-bit Embedded Controller
logo
Freescale Semiconductor...
MCF5271EC FREESCALE-MCF5271EC Datasheet
1Mb / 56P
   32-bit Embedded Controller Division
logo
Winbond
PC97551 WINBOND-PC97551 Datasheet
268Kb / 6P
   Embedded Controller for Notebook Systems
February 2006 Revision 1.1
87541V WINBOND-87541V Datasheet
135Kb / 4P
   Embedded Controller for Mobile Systems
logo
Intel Corporation
M82380 INTEL-M82380 Datasheet
1Mb / 134P
   HIGH PERFORMANCE 32-BIT DMA CONTROLLER WITH INTEGRATED SYSTEM SUPPORT PERIPHERALS
logo
Microchip Technology
MM7150 MICROCHIP-MM7150 Datasheet
316Kb / 28P
   High Performance 32-bit Embedded Controller
01/27/15
logo
Sharp Corporation
LH79525 SHARP-LH79525 Datasheet
132Kb / 2P
   16/32-bit System-on-Chip with Color LCD Controller
logo
Motorola, Inc
MC68EC030 MOTOROLA-MC68EC030 Datasheet
392Kb / 36P
   Second-Generation 32-Bit Enhanced Embedded Controller
More results


Html Pages

1 2 3 4 5 6


Datasheet Download

Go To PDF Page


Link URL




Privacy Policy
ALLDATASHEET.NET
Does ALLDATASHEET help your business so far?  [ DONATE ] 

About Alldatasheet   |   Advertisement   |   Contact us   |   Privacy Policy   |   Link Exchange   |   Manufacturer List
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com