Electronic Components Datasheet Search
  English  ▼
ALLDATASHEET.COM

X  

IDT70V25L15PFG Datasheet(PDF) 24 Page - Integrated Device Technology

Part # IDT70V25L15PFG
Description  HIGH-SPEED 3.3V STATIC RAM
Download  25 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  IDT [Integrated Device Technology]
Direct Link  http://www.idt.com
Logo IDT - Integrated Device Technology

IDT70V25L15PFG Datasheet(HTML) 24 Page - Integrated Device Technology

Back Button IDT70V25L15PFG Datasheet HTML 17Page - Integrated Device Technology IDT70V25L15PFG Datasheet HTML 18Page - Integrated Device Technology IDT70V25L15PFG Datasheet HTML 19Page - Integrated Device Technology IDT70V25L15PFG Datasheet HTML 20Page - Integrated Device Technology IDT70V25L15PFG Datasheet HTML 21Page - Integrated Device Technology IDT70V25L15PFG Datasheet HTML 22Page - Integrated Device Technology IDT70V25L15PFG Datasheet HTML 23Page - Integrated Device Technology IDT70V25L15PFG Datasheet HTML 24Page - Integrated Device Technology IDT70V25L15PFG Datasheet HTML 25Page - Integrated Device Technology  
Zoom Inzoom in Zoom Outzoom out
 24 / 25 page
background image
6.42
IDT70V35/34S/L
(IDT70V25/24S/L)
High-Speed 3.3V 8/4K x 18 (8/4K x 16) Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
24
semaphore request latch. The critical case of semaphore timing is when
both sides request a single token by attempting to write a zero into it at the
same time. The semaphore logic is specially designed to resolve this
problem.Ifsimultaneousrequestsaremade,thelogicguaranteesthatonly
one side receives the token. If one side is earlier than the other in making
therequest,thefirstsidetomaketherequestwillreceivethetoken.Ifboth
requests arrive at the same time, the assignment will be arbitrarily made
to one port or the other.
One caution that should be noted when using semaphores is that
semaphores alone do not guarantee that access to a resource is secure.
Aswithanypowerfulprogrammingtechnique,ifsemaphoresaremisused
or misinterpreted, a software error can easily happen.
Initializationofthesemaphoresisnotautomaticandmustbehandled
via the initialization program at power-up. Since any semaphore request
flag which contains a zero must be reset to a one, all semaphores on both
sides should have a one written into them at initialization from both sides
to assure that they will be free when needed.
Using Semaphores—Some Examples
Perhapsthesimplestapplicationofsemaphoresistheirapplicationas
resource markers for the IDT70V35/34 (IDT70V25/24)’s Dual-Port
SRAM. Say the 8K x 18 SRAM was to be divided into two 4K x 18 blocks
which were to be dedicated at any one time to servicing either the left or
right port. Semaphore 0 could be used to indicate the side which would
control the lower section of memory, and Semaphore 1 could be defined
as the indicator for the upper section of memory.
To take a resource, in this example the lower 4K of Dual-Port SRAM,
the processor on the left port could write and then read a zero in to
Semaphore 0. If this task were successfully completed (a zero was read
back rather than a one), the left processor would assume control of the
lower4K.Meanwhiletherightprocessorwasattemptingtogaincontrolof
the resourceaftertheleftprocessor,itwouldreadbackaoneinresponse
to the zero it had attempted to write into Semaphore 0. At this point, the
software could choose to try and gain control of the second 4K section by
writing, then reading a zero into Semaphore 1. If it succeeded in gaining
control, it would lock out the left side.
Once the left side was finished with its task, it would write a one to
Semaphore 0 and may then try to gain access to Semaphore 1. If
Semaphore 1 was still occupied by the right side, the left side could undo
itssemaphorerequestandperformothertasksuntilitwasabletowrite,then
readazerointoSemaphore1.Iftherightprocessorperformsasimilartask
with Semaphore 0, this protocol would allow the two processors to swap
4K blocks of Dual-Port SRAM with each other.
The blocks do not have to be any particular size and can even be
variable, depending upon the complexity of the software using the
semaphore flags. All eight semaphores could be used to divide the Dual-
Port SRAM or other shared resources into eight parts. Semaphores can
even be assigned different meanings on different sides rather than being
given a common meaning as was shown in the example above.
Semaphores are a useful form of arbitration in systems like disk
interfaceswheretheCPUmustbelockedoutofasectionofmemoryduring
a transfer and the I/O device cannot tolerate any wait states. With the use
ofsemaphores,oncethetwodeviceshasdeterminedwhichmemoryarea
was“off-limits”totheCPU,boththeCPUandtheI/Odevicescouldaccess
their assigned portions of memory continuously without any wait states.
Semaphoresarealsousefulinapplicationswherenomemory“WAIT”
stateisavailableononeorbothsides.Onceasemaphorehandshakehas
been performed, both processors can access their assigned RAM
segments at full speed.
Another application is in the area of complex data structures. In this
case,blockarbitrationisveryimportant.Forthisapplicationoneprocessor
may be responsible for building and updating a data structure. The other
processor then reads and interprets that data structure. If the interpreting
processorreadsanincompletedatastructure,amajorerrorconditionmay
exist. Therefore, some sort of arbitration must be used between the two
differentprocessors.Thebuildingprocessorarbitratesfortheblock,locks
it and then is able to go in and update the data structure. When the update
is completed, the data structure block is released. This allows the
interpretingprocessortocomebackandreadthecompletedatastructure,
thereby guaranteeing a consistent data structure.
D
5624 drw 20
0
D
Q
WRITE
D0
D
Q
WRITE
SEMAPHORE
REQUEST FLIP FLOP
SEMAPHORE
REQUEST FLIP FLOP
L PORT
RPORT
SEMAPHORE
READ
SEMAPHORE
READ
,
Figure 4.
IDT70V35/34 (IDT70V25/24) Semaphore Logic


Similar Part No. - IDT70V25L15PFG

ManufacturerPart #DatasheetDescription
logo
Integrated Device Techn...
IDT70V25L15PF IDT-IDT70V25L15PF Datasheet
186Kb / 22P
   HIGH-SPEED 3.3V 8K x 16 DUAL-PORT STATIC RAM
IDT70V25L15PFI IDT-IDT70V25L15PFI Datasheet
186Kb / 22P
   HIGH-SPEED 3.3V 8K x 16 DUAL-PORT STATIC RAM
More results

Similar Description - IDT70V25L15PFG

ManufacturerPart #DatasheetDescription
logo
Integrated Device Techn...
IDT70V3599 IDT-IDT70V3599_18 Datasheet
271Kb / 23P
   HIGH-SPEED 3.3V SYNCHRONOUS DUAL-PORT STATIC RAM
logo
Samsung semiconductor
K6R4016V1C-C SAMSUNG-K6R4016V1C-C Datasheet
190Kb / 11P
   256Kx16 Bit High Speed Static RAM(3.3V Operating)
K6R4016V1D SAMSUNG-K6R4016V1D Datasheet
227Kb / 12P
   256Kx16 Bit High Speed Static RAM(3.3V Operating)
logo
Integrated Device Techn...
IDT7006SL IDT-IDT7006SL Datasheet
188Kb / 20P
   HIGH-SPEED HIGH-SPEED STATIC RAM
logo
List of Unclassifed Man...
P3C1024 ETC1-P3C1024 Datasheet
45Kb / 2P
   HIGH SPEED 128K x 8 3.3V STATIC CMOS RAM
logo
Integrated Device Techn...
IDT70V3569S IDT-IDT70V3569S_18 Datasheet
211Kb / 17P
   HIGH-SPEED 3.3V SYNCHRONOUS PIPELINED DUAL-PORT STATIC RAM
IDT70V3579S IDT-IDT70V3579S_18 Datasheet
208Kb / 17P
   HIGH-SPEED 3.3V SYNCHRONOUS PIPELINED DUAL-PORT STATIC RAM
logo
Pyramid Semiconductor C...
P3C1256 PYRAMID-P3C1256 Datasheet
265Kb / 10P
   HIGH SPEED 32K x 8 3.3V STATIC CMOS RAM
logo
Integrated Device Techn...
IDT70V9199 IDT-IDT70V9199_18 Datasheet
203Kb / 17P
   HIGH-SPEED 3.3V SYNCHRONOUS PIPELINED DUAL-PORT STATIC RAM
IDT70V37L IDT-IDT70V37L Datasheet
158Kb / 17P
   HIGH-SPEED 3.3V 32K x 18 DUAL- STATIC RAM
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25


Datasheet Download

Go To PDF Page


Link URL




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

About Alldatasheet   |   Advertisement   |   Datasheet Upload   |   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