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本帖最后由 yuzengshu 于 2009-11-5 13:19 编辑
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CPCI 分为系统板，背板，外围板，对于外围板有死规范，但是对于，系统板，和背板的规范; k5 l. G9 g$ n4 P: a1 d
，见的不多，就是对于系统板，时钟线和数据线的长度有没有限定，还有背板，时钟和数据长度的限定怎么- b! z A |: A; [! N
计算，希望做过的朋友，给点经验，我的是PCI TO PCI桥出来，在到CPCI接口的，谢谢# z8 a1 u# c' ~7 M. Z
大家看看这段怎么理解7 Z# n& V j, T6 S* ]6 ]: ~
1 The System Slot clock distribution circuitry shall be designed to accommodate
( l; d) a. g8 m. Uup to 200 ps of backplane and peripheral board skew. The following design rules% h9 f( G) i5 R4 Y) G
apply to clock distribution to backplane peripherals and local (onboard) PCI0 H" J0 \- s# g$ H; H- ^0 s
peripherals( |$ Z( k. l: f' w8 }! }! z; e4 O
2 Any onboard PCI peripherals connected to the CompactPCI bus, including" g0 i3 c2 p: a! o0 z( n
PCI to PCI bridges, shall be provided a clock that is delayed to3 }6 \0 ?3 _5 S2 t0 ?/ b% p
accommodate the maximum propagation delay of the backplane clocks and: L; m; B. z$ Q6 G& |( s
still meet the 1 ns overall skew requirement. Up to 800 ps of skew is# h1 I- O, Q) l7 l6 I8 I
allowed for onboard clock distribution (including the clock buffer internal2 D6 k g4 v$ G# Y% d Q
skew). The onboard clock signals shall be delayed beyond the clocks routed
, F/ p- X1 G9 S! B8 O( C) ? Eto the backplane (Section 3.5.5.1) to accommodate best and worst case5 q# l, S9 g; i0 @
backplane delays and the 63.5mm wire delay on the peripheral board. |
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发表于 2009-11-5 13:17
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支持！
反对！