: P# D/ {+ Y. ]) v如果布正確的話....8 b% `8 L3 {2 o6 b% \1 u+ S1 w
能麻煩各位幫我做個詳細的解說嗎?? - S ^0 V3 e0 W+ J6 z! k) t% L; \( l4 Z3 ~
先說聲謝謝~0 ]! \* y2 u! e$ ]
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----------以下是DATASHEET針對VCCIO & VCCINT所做的說明------------ 9 t" J% Z; X3 i( n & R, A+ n! e, H* A9 f, }* eMultiVolt I/O Interface 2 W; R. O/ V2 M' @# U: [2 K5 Y1 D; z. ~& r
MAX 7000 devices—except 44-pin devices—support the MultiVolt I/O 0 j& d1 d3 k# _' f \interface feature, which allows MAX 7000 devices to interface with 8 J1 W$ |1 s; ?' D7 {9 x S% tsystems that have differing supply voltages. The 5.0-V devices in all 8 Q* t7 _+ K- A9 B- ^packages can be set for 3.3-V or 5.0-V I/O pin operation. These devices9 N/ `& M, m: C$ P; K9 N7 S1 I6 _
have one set of VCC pins for internal operation and input buffers+ t; i! E* S5 K6 r) h* ~! c" S
(VCCINT), and another set for I/O output drivers (VCCIO). ; \- m" h( }9 z8 H) GThe VCCINT pins must always be connected to a 5.0-V power supply. - q; g1 `1 c8 G; [7 ]; j' eWith a 5.0-V VCCINT level, input voltage thresholds are at TTL levels, and $ r3 L# u R7 a T0 O3 [are therefore compatible with both 3.3-V and 5.0-V inputs.7 t( u( P1 o, E# j0 u
The VCCIO pins can be connected to either a 3.3-V or a 5.0-V power6 z K( v. P$ `2 M4 q
supply, depending on the output requirements. When the VCCIO pins are# l) F4 h# ^8 j2 V
connected to a 5.0-V supply, the output levels are compatible with 5.0-V 8 C% B# `) Q1 }systems. When VCCIO is connected to a 3.3-V supply, the output high is 7 @- }5 s7 z! x, @8 U/ `% e3.3 V and is therefore compatible with 3.3-V or 5.0-V systems. Devices4 {9 U2 N* s0 N8 g- s
operating with VCCIO levels lower than 4.75 V incur a nominally greater, c% s4 k, c4 O3 d: B) z
timing delay of tOD2 instead of tOD1. 1 X9 i, |1 a+ V. u) J% |1 X S6 [% z& x1 c9 b
[ 本帖最後由 jimcooper 於 2008-11-9 04:21 PM 編輯 ]作者: sieg70 時間: 2008-11-10 07:54 AM
Vccint跟Vccio, 以及Ground"每根"都要接作者: addn 時間: 2008-11-10 10:04 AM
您好* y! O- [) X" E4 i7 a' I
VCCINT接5v,則當io pin為輸入時,可接受3.3v,5v的輸入準位 2 D( U: l" S# `% d3 WVCCIO接5v/3.3v,則當io pin為輸出時,輸出準位就為5v/3.3v準為位: S1 H: D, f: O6 k' o5 s