參數(shù)資料
型號(hào): 82C836A-20
廠商: Electronic Theatre Controls, Inc.
英文描述: Single-Chip 386sx AT
中文描述: 單芯片386sx在
文件頁數(shù): 152/205頁
文件大?。?/td> 3878K
代理商: 82C836A-20
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頁當(dāng)前第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頁第189頁第190頁第191頁第192頁第193頁第194頁第195頁第196頁第197頁第198頁第199頁第200頁第201頁第202頁第203頁第204頁第205頁
The 80387sx coprocessor monitors -ADS, -READY, and CPU address bit 23 directly to
detect I/O operations addressed to it. The coprocessor operates roughly as a 16-bit data
resource except as follows:
1.
In all cases, coprocessor data is exchanged on the CPU local data bus, not on the AT
bus. -IOCS16 is not asserted.
If no coprocessor is present, attempted coprocessor I/O accesses result in bus convert
cycles, including ALE and command on the AT bus, but the data bus drivers in the
82C836 remain tristated. This allows plenty of time for the floating CPU data bus to
stablize to a valid state (a stable data bus is important for compatibility with certain
older software products that rely on attempted coprocessor I/O operations to detect
coprocessor presence or absence).
If a coprocessor is present, but the 82C836 has been programmed to generate -READY
during coprocessor accesses, ALE and command are generated. The cycle follows
normal 16-bit I/O timing except as mentioned in (1) above.
If a coprocessor is present and the 82C836 has been programmed to rely on the
coprocessor to generate -READY, ALE and command are not generated, and the
cycle ends as soon as the coprocessor issues -READY, which may be considerably
sooner than in (3) above. Zero wait state cycles are possible when the coprocessor
generates -READY.
2.
3.
4.
Since the coprocessor interface is tighly coupled to the CPU (rather than using an
-XIOR/-XIOW interface), the coprocessor is not accessible by add-on card bus masters.
DMA Timing
Figure 11-12 shows a DMA operation consisting of two back-to-back DMA transfers
between a memory resource and an I/O resource. The general protocol is as follows:
A DMA requestor asserts an assigned DREQ signal. The 82C836 then asserts HOLD
to the CPU.
Eventually the CPU responds with HLDA, causing AEN to be asserted on the AT bus
(externally gated with -MASTER). HLDA also causes ALE to be asserted. ALE
remains continuously asserted until HOLD is subsequently deasserted.
Some time after detecting HLDA, the 82C836 generates the DMA memory address
and issues the appripriate -DACK signal, followed by either -XIOR and -XMEMW, or
XMEMR- and -XIOW.
The address bus contains the memory address and is used by the memory resource.
The I/O resource that should respond to the DMA cycle is determined by the -DACK
signal. Other I/O resources not involved in the DMA cycle generally rely on AEN to
signify the address on the bus is not an I/O address.
I
CPU Access to AT-Bus
System Timing Relationships
11-20
Revision 3.0
P R E L I M I N A R Y
Chips and Technologies, Inc.
相關(guān)PDF資料
PDF描述
82C836B Single-Chip 386sx AT
82C862 FireLink USB Dual Controller Quad Port USB
82C931 Plug and Play Integrated Audio Controller
82S09 576-BIT BIPOLAR RAM (64 X 9)
82S19 576-BIT BIPOLAR RAM (64 X 9)
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
82C836B 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Single-Chip 386sx AT
82C83H 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:CMOS Octal Latching Inverting Bus Driver
82C84 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:CMOS Clock Generator Driver
82C84A 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:CMOS Clock Generator Driver
82C84A/B 制造商: 功能描述: 制造商:undefined 功能描述: