Kev khiav lag luam nco tau ntawm lub khoos phis tawm niaj hnub no yog tus cwj pwm los ntawm ntau cov tsis. Cov nto moo tshaj plaws yog ntim thiab ntau zaus, tab sis nco latency, tsis li hu ua lub sijhawm, tseem yog qhov ntsuas tseem ceeb.
Lub khoos phis tawj nkag mus siv lub cim xeeb (RAM) yog qhov nco tau yooj yim uas muaj OS cov khoom siv thiab cov kev pabcuam. Tus nqi ntawm lub cim xeeb cuam tshuam ntau npaum li cas cov ntaub ntawv nws tuaj yeem ntim tau tib lub sijhawm, thiab, raws li, cov lej tau khiav ntawm cov ntawv thov. Zaus qhia txog qhov ceev ntawm lub cim xeeb, uas yog, tus naj npawb ntawm cov haujlwm (voj voog) ib ob.
Lub peev txheej ntawm lub cim xeeb hauv computer tau tsim hauv 1834 los ntawm Charles Babbage. Qhov cuab yeej siv tshuab no, hu ua lub khw muag khoom, khaws cov khoom siv nrab ntawm kev tshuaj ntsuam cav xam.
Lub sijhawm sib txawv, lossis sijhawm, qhia cov lej siv sijhawm siv rau kev ua haujlwm sab hauv, ua lwm yam lus, sijhawm ua ke cim qhov cim xeeb yooj yim.
Cov ntsiab lus nco nkag
Txhawm rau kom nkag siab cov sijhawm no lossis cov sijhawm, nws tsim nyog nyob hauv kev qhia ntxiv ntawm kev nkag mus cim xeeb. Yooj yim dua, lub cim xeeb nti tuaj yeem raug sawv cev raws li lub rooj, qhov chaw ntawm txhua lub xov tooj sib raug rau lub cim xeeb uas khaws ib qho me ntsis.
Thaum xaiv cov cell tshwj xeeb, kem kab thiab kab yog xa ntawm lub npav npav qhov chaw nyob. Thawj thawj yog Row Access Strobe (RAS), tom qab ntawv Column Access Strobe (CAS).
Tom qab xaiv lub xov tooj ntawm tes, ntau qhov kev tswj hwm lub zog raug xa mus rau nws - kuaj xyuas kev nkag tau sau, sau ntawv, nyeem lossis rov nkag. Ntxiv mus, muaj kev ncua ntawm cov haujlwm no, uas yog hu ua sijhawm.
Sijhawm poob sijhawm
Muaj plaub lub sijhawm sib txawv raws li teev tseg los ntawm cov chaw tsim khoom siv cim xeeb.
CL (CAS-latensy) - CAS latency yog tos ntawm CAS mem tes thiab pib nyeem. Hauv lwm lo lus, tus naj npawb ntawm cov zuam yuav tsum tau nyeem ib lub xov tooj ntawm tes, yog tias kab xav tau twb tau qhib lawm.
T RCD (Kab nyob rau Ntu Chaw Nyob Xa Lus Txuas) - ncua ntawm RAS thiab CAS pulses. Sijhawm qhia pom lub sijhawm ntawm kev qhib ib kab thiab qhib ib kem.
T RP (Lub Sijhawm Them Ua Ntej). Lub sijhawm no yog ncua sij hawm nruab nrab ntawm lub impulse los kaw cov kab nquag thiab RAS impulse los qhib ib qho tom ntej.
Qee lub sij hawm koj tuaj yeem hla cov ntaub ntawv zoo li 6-6-6-18-24. Ntawm no tus lej thib tsib txhais tau hais tias kom ua tus nqi raws sij hawm - ncua sij hawm nruab nrab ntawm cov mem tes rau xaiv microcircuit hauv lub cim xeeb module thiab ua kom cov kab.
Qhov tag nrho ntawm cov sijhawm no cim qhov ncua sij hawm nyeem ib lub xov tooj ntawm lub cim xeeb tshwj xeeb yog lwm txoj kab qhib. Cov neeg tsim khoom feem ntau qhia txog peb qhov kev ntsuas no, tab sis qee zaus koj tuaj yeem pom lub plaub - T RAS.
T RAS (Row Active Time) - tus naj npawb ntawm cov zuam nruab nrab ntawm RAS mem tes thiab mem tes uas kaw cov kab (Ua Haujlwm Them Ua Haujlwm), uas yog, cov sijhawm hloov tshiab. Feem ntau, T RAS sib npaug li peb lub sijhawm ua ntej.
Rau qhov yooj yim, sijhawm tau muab cov cim tsis muaj cim, sib cais los ntawm ib qho hyphen, piv txwv, 2-2-2 lossis 2-2-2-6.
