,,,
̳ i
,
' Ͳє
:
. . -07-1
. .
:
. .
. .
2008
̲
1. ' ............................. 3
1.1 ' ......................................................................... 3
1.2 ϳ-....................................................................... 6
1.3 ........................................................... 7
1.4 .................................................. 7
1.5 ............................................................................. 8
2. ' 䳿..11
2.1 FPM............................................................................................. ...11
2.2 EDORAM....................................................................... ...12
2.3 BEDORAM.................................................................... ...13
2.4 MDRAM......................................................................... ...13
2.5 SDRAM.......................................................................... ...14
2.6 RDRAM......................................................................... ...17
2.7 DRDRAM............................................................................... ...17
2.8 CDRAM......................................................................... ...18
3.
' .18
4. ......................................................................... ...21
5. ˳...................................................................................................... ...23
' -
(DRAM) - () . , 6 , ( 45 ) . , ( ).
'
³ . - , , α-, ().
. 1. .
. 1. - . . . ̳ - Si02.
. , . ' - - -. - , .
' . (. 2) , () 1 0 . - () , . , .
. 2. .
. .
. , U/2. , , .
, .
, . ΔU, , . , , U . ' ΔU. . 3.
. 3. .
ΔU . .
Q = UCC/2.
ϳ + :
Q = (+ )(UCC/2 ΔU).
Q,
UCC/2 = (+ )(UCC/2 ΔU),
ΔU = UCC/[2(+)] ≈ UCC/[2 ].
<< ΔU . , - ' .
̳ ( ), - .
( ҳ2), 20 , Si2. 20 . , .
"" (. 4, ). , , ' , ΔU.
. 4. - - () - ().
ϳ-
ϳ- . (. 4, ) "ϳ" 1 2. "ϳ" . - . , , U/2, , , ΔU , . T1 2. "ϳ" . T1 2 , , , . , . . -, . . , .
. , , . . RAS (Row Address Strobe), - CAS (Column Address Strobe). , , RAS CAS - (, ). , , , . , 161 24- , 12.
. 5 . . .
. 5. .
(. 6) , . , . - .
( ) , , 1 U/2 - . ( ). 1 - U/2, 1 1 2. 1 , , .
. 6. .
-, , , .
2 "ϳ" -, , - , .
R/W, ( 4 R/W = 1), ( 3 R/W = 0).
, , ' , ( , ) 1 2.
, , , "--". , (). , , . , . "--" , , .
' 䳿
䳺. , . , ' '.
䳿. , , . , , .
FPM
FPM (Fast Page Mode, ) , . .
, . , , .
(), , ( RAS), . , CAS. 3 4 (. . 6). , , .
FPM . 7. , RA ( ). : 5-3-3-... .
. 7. FPM .
FPM 䳿 . 䳿 , FPM , .
FPM : (), . () . FPM 30-40 , 33 .
EDORAM
EDORAM (Extended Data Out RAM, ) FPM . EDORAM -
EDORAM 50 . , FPM, EDORAM .
BEDORAM
BEDORAM (Burst EDORAM, ) . () . . 5-1-1-1 ( , 4). ' BEDORAM - DRAM (SDRAM), 5-1-1-1, .
MDRAM
MDRAM (Multibank DRAM, ) ' (). , . , , ' . '. , .
, ' , , - . MDRAM DRAM - .
SDRAM
DRAM FPM EDORAM ', ' . ' SDRAM (Synchronous DRAM) ' .
SDRAM ' ' , , ' .
DRAM 1994 . , 250 /. ֳ 125 U = 3,3 0,5 . (113,7 2) DRAM .
' SDRAM . . . 8 , . , :
Tmin = tpr + t + tSU ,
tpr - "-"; t - ( ); tSU - .
Tmin, , t , (. 8, ). , , , . 8, , .
. 8. () () .
, , , , .
SDRAM , . ACT (Active) ' . RED (Read) . PRE (Precharge) ' .
' (Access Latency). "", , . , ' (. 9, ). , (. 9, 6). . ³ (. 9, ).
SDRAM ' , .
. 9. (), () () .
SDRAM , . , () , . SDRAM ' .
RDRAM
̳ - Rambus (RDRAM Rambus DRAM). - ' . Rambus Channel. SDRAM.
250 500 (2 /). 1,5...3 .
Rambus Channel 13 , , '. . , . , ' , . . 128 . RDRAM . . 256 400 ( 2 0,5 ), 64 - 250 ..
RDRAM - .
DRDRAM
RDRAM, Direct RDRAM (DRDRAM). RDRAM , . , DRDRAM.
DRAM (SDRAM). ' , ', . ' DRDRAM . , SDRAM, DRDRAM , DRAM. . DRDRAM 16- ( RDRAM 8-). 400 DDR (Double Data Rate), , DRDRAM (Bandwidth) 1,6 /.
, , , 1,6 / .
CDRAM
CDRAM (Cached DRAM, DRAM) DRAM -' ( ). , , . ' , DRAM ' ( ), . , CDRAM Ramtron 2048- .
CDRAM EDRAM (Enhanced DRAM). , , , .
'
. ( 1 15 ).
. , . , .
tCY, N, t = tCYN. ³
τ = (t/ )
- .
, 1 1Mx1, 100 , 5 ,
τ = (100∙10-9∙210/5∙10-3) ∙100% = 2%
(210 = 1024 , 1 ' ).
, , . 10. ' , . . , - . 1 2 . 2 CTR, - RASp MUX2 MUX1.
. 10. .
'
G , . ij , ( ). , , ' , 1 . HOLD ' . . , . , HLDA, . HLDA 2, ', per, MUX2 CTR . 2 , ( 64). 1, HOLD. HLDA, 2, .
-' . ', . .
" " . 11, , . . 11, , . 11, , ' 䳿 . , . .
. 11. 䳿 () () ' .
˳
1. .. .: ., 1987. 424 .
2. . . C-, 2004. 528 .
3. . . . .: , 1993. 63 .: .
4. Internet: [ ] .: [200-?]. : http://www.whatis.ru/hard/mem.shtml . .
̳ i ,
Copyright (c) 2024 Stud-Baza.ru , , , .