參數(shù)資料
型號: SYM53C810A
廠商: LSI Corporation
英文描述: PCI-SCSI I/O Processor(PCI-SCSI I/O接口處理器)
中文描述: 的PCI -的SCSI I / O處理器(個PCI -的SCSI的I / O接口處理器)
文件頁數(shù): 33/188頁
文件大?。?/td> 1120K
代理商: SYM53C810A
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁當前第33頁第34頁第35頁第36頁第37頁第38頁第39頁第40頁第41頁第42頁第43頁第44頁第45頁第46頁第47頁第48頁第49頁第50頁第51頁第52頁第53頁第54頁第55頁第56頁第57頁第58頁第59頁第60頁第61頁第62頁第63頁第64頁第65頁第66頁第67頁第68頁第69頁第70頁第71頁第72頁第73頁第74頁第75頁第76頁第77頁第78頁第79頁第80頁第81頁第82頁第83頁第84頁第85頁第86頁第87頁第88頁第89頁第90頁第91頁第92頁第93頁第94頁第95頁第96頁第97頁第98頁第99頁第100頁第101頁第102頁第103頁第104頁第105頁第106頁第107頁第108頁第109頁第110頁第111頁第112頁第113頁第114頁第115頁第116頁第117頁第118頁第119頁第120頁第121頁第122頁第123頁第124頁第125頁第126頁第127頁第128頁第129頁第130頁第131頁第132頁第133頁第134頁第135頁第136頁第137頁第138頁第139頁第140頁第141頁第142頁第143頁第144頁第145頁第146頁第147頁第148頁第149頁第150頁第151頁第152頁第153頁第154頁第155頁第156頁第157頁第158頁第159頁第160頁第161頁第162頁第163頁第164頁第165頁第166頁第167頁第168頁第169頁第170頁第171頁第172頁第173頁第174頁第175頁第176頁第177頁第178頁第179頁第180頁第181頁第182頁第183頁第184頁第185頁第186頁第187頁第188頁
Functional Description
Synchronous Operation
SYM53C810A Data Manual
2-11
Synchronous Operation
T he SYM53C810A can transfer synchronous
SCSI data in both initiator and target modes. T he
SX FER register controls both the synchronous off-
set and the transfer period. It may be loaded by the
CPU before SCRIPT S execution begins, from
within SCRIPT S via a Table Indirect I/O instruc-
tion, or with a Read-Modify-Write instruction.
T he SYM53C810A can receive data from the
SCSI bus at a synchronous transfer period as short
as 80 ns or 160 ns (with a 50 MHz clock), regard-
less of the transfer period used to send data. T he
SYM53C810A can receive data at one-fourth of
the divided SCLK frequency. Depending on the
SCLK frequency, the negotiated transfer period,
and the synchronous clock divider, the
SYM53C810A can send synchronous data at
intervals as short as 100 ns for fast SCSI-2 and
200 ns for SCSI-1.
Determining the
Data Transfer Rate
Synchronous data transfer rates are controlled by
bits in two different registers of the
SYM53C810A. A brief description of the bits is
provided below. Figure 2-4 illustrates the clock
division factors used in each register, and the role
of the register bits in determining the transfer rate.
SCNT L3 Register, bits 6–4 (SCF2–0)
T he SCF2-0 bits select the factor by which the fre-
quency of SCLK is divided before being presented
to the synchronous SCSI control logic. T he output
from this divider controls the rate at which data
can be received; this rate must not exceed 50
MHz. T he receive rate is 1/4 of the divider output.
For example, if SCLK is 40MHz and the SCF
value is set to divide by one, then the maximum
rate at which data can be received is 10 MB/s (40/
(1*4) = 10).
For synchronous send, the output of the SCF
divider is divided by the transfer period (X FERP)
bits in the SCSI Transfer (SX FER) register. For
valid combinations of the SCF and the X FERP,
see Table 5-4 and Table 5-5, under the description
of the X FERP bits 7-5 in the SX FER register.
SCNT L3 Register, bits 2–0 (CCF2–0)
T he CCF2-0 bits select the frequency of the
SCLK for asynchronous SCSI operations. To meet
the SCSI timings as defined by the ANSI specifica-
tion, these bits need to be set properly.
SX FE R Register, bits 7–5 (T P2–0)
T he T P2-0 divider (X FERP) bits determine the
SCSI synchronous send rate in either initiator or
target mode. T his value further divides the output
from the SCF divider.
Achieving Optimal SCSI Send Rates
To achieve optimal synchronous SCSI send tim-
ings, the SCF divisor value should be set high, to
divide the clock as much as possible before pre-
senting the clock to the T P divider bits in the
SX FER register. T he T P2-0 divider value should
be as low as possible. For example, with 40 MHz
clock to achieve a 5 MB/s send rate, the SCF bits
can be set to divide by 1 and the T P bits to divide
by 8; or the SCF bits can be set to divide by 2 and
the T P bits set to divide by 4. Use the second
option to achieve optimal SCSI timings.
相關PDF資料
PDF描述
SYM53C825A PCI-SCSI I/O Processor(PCI-SCSI I/O接口處理器)
SYM53C825AE PCI-SCSI I/O Processor(PCI-SCSI I/O接口處理器)
SYM53C860 Single-Chip High-Performance PCI-Ultra SCSI (Fast-20) I/O Processor(單片、高性能PCI-超級SCSI (Fast-20) I/O 處理器)
SYM53C875 PCI-Ultra SCSI I/O Processor(PCI-Ultra SCSI I/O處理器)
SYM53C875E PCI-Ultra SCSI I/O Processor(PCI-Ultra SCSI I/O 處理器)
相關代理商/技術參數(shù)
參數(shù)描述
SYM53C876E(PBGA) 制造商:未知廠家 制造商全稱:未知廠家 功能描述:SCSI Bus Interface/Controller
SYM53C876E(PQFP) 制造商:未知廠家 制造商全稱:未知廠家 功能描述:SCSI Bus Interface/Controller
SYM53C885 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Telecommunication IC
SYM53C896 制造商:未知廠家 制造商全稱:未知廠家 功能描述:BUS CONTROLLER
SYM-63LH+ 制造商:MINI 制造商全稱:Mini-Circuits 功能描述:Frequency Mixer