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請問一下VCCINT & VCCIO還有其對應的GND 這些腳位是做甚麼用的啊??
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( r/ n* c1 c; H我已經看我DATASHEET上對這方面的說明,但感覺還是有點不清楚
J, X; v4 j1 X/ D% x. s感覺上VCCINT & VCCIO好像只需要各接一隻腳就可以了,其他相同名稱的腳位都是相通的.....
1 ]7 @. R6 H9 G' c我的想法正確嗎??$ |$ [: n9 u$ \2 ?( O) D5 l5 r; L4 [/ F
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如果布正確的話....! v- ~0 }) e$ J+ O; ?; _( U
能麻煩各位幫我做個詳細的解說嗎??
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2 w6 O. e z7 ~2 K9 X1 M; `" d. L先說聲謝謝~
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( q" R2 ?* L: j) Y# Q4 n----------以下是DATASHEET針對VCCIO & VCCINT所做的說明------------ f- J+ O; g* X' r5 {$ v, O8 \5 f
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MultiVolt I/O Interface
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8 A: w, c( K8 G8 DMAX 7000 devices—except 44-pin devices—support the MultiVolt I/O9 z. }, [3 z! Y4 f; L
interface feature, which allows MAX 7000 devices to interface with) b" l! t" r: o: V9 z. o# W6 i
systems that have differing supply voltages. The 5.0-V devices in all A" R' o( W6 a0 ?9 k& p: h$ V
packages can be set for 3.3-V or 5.0-V I/O pin operation. These devices' D% @( q1 p# s0 ?* M7 B
have one set of VCC pins for internal operation and input buffers, f5 ~ G C' I& Q) O1 H
(VCCINT), and another set for I/O output drivers (VCCIO).
4 E b: p( G# Z/ ]. pThe VCCINT pins must always be connected to a 5.0-V power supply.
- q1 D& v2 ^# o" t9 k/ S0 UWith a 5.0-V VCCINT level, input voltage thresholds are at TTL levels, and- i* p& z/ l$ @: q8 J3 H
are therefore compatible with both 3.3-V and 5.0-V inputs.
5 b9 R c7 U) D. q' X0 iThe VCCIO pins can be connected to either a 3.3-V or a 5.0-V power
% L; t; \. o" S& k' u* l" c) ^supply, depending on the output requirements. When the VCCIO pins are9 Y# M, D. ?- p
connected to a 5.0-V supply, the output levels are compatible with 5.0-V
2 @! B. e1 ^. a, Z% `systems. When VCCIO is connected to a 3.3-V supply, the output high is1 A. k4 w# }, M {/ i
3.3 V and is therefore compatible with 3.3-V or 5.0-V systems. Devices
; G) m1 I1 C3 K2 t" v0 moperating with VCCIO levels lower than 4.75 V incur a nominally greater8 v6 z8 b0 }) d' w' g# Z0 A1 R% A/ j
timing delay of tOD2 instead of tOD1.
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[ 本帖最後由 jimcooper 於 2008-11-9 04:21 PM 編輯 ] |
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