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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??+ |- \$ n7 e. B9 \, W/ |
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我已經看我DATASHEET上對這方面的說明,但感覺還是有點不清楚
( s: V( H |: t |) G+ M7 Y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.....% A7 Q+ U$ r. I" }
我的想法正確嗎??1 Y% K, d9 t+ t2 G3 ~) T6 T
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如果布正確的話....! O6 x" A+ @1 ]" E
能麻煩各位幫我做個詳細的解說嗎??
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9 G- ~5 u5 s* O: \% H& I. z0 A先說聲謝謝~8 \! `: C% d8 j& { f
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----------以下是DATASHEET針對VCCIO & VCCINT所做的說明------------
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' s" s8 l* C: J* ?& ?/ rMultiVolt I/O Interface
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MAX 7000 devices—except 44-pin devices—support the MultiVolt I/O
2 Z" G6 T, z/ ^: n7 j+ minterface feature, which allows MAX 7000 devices to interface with
- f/ r% U$ ~: O+ Q5 F% G" w, Rsystems that have differing supply voltages. The 5.0-V devices in all
+ n4 N! W( d& C; }7 N5 apackages can be set for 3.3-V or 5.0-V I/O pin operation. These devices% @4 ^4 u2 ?0 Q7 s* E6 J
have one set of VCC pins for internal operation and input buffers
0 K% r. r9 K5 S7 t3 j(VCCINT), and another set for I/O output drivers (VCCIO).6 J+ x0 k' }# t6 R' @0 f+ ~# L
The VCCINT pins must always be connected to a 5.0-V power supply.
- ]) f: s* Z) x3 N6 `5 SWith a 5.0-V VCCINT level, input voltage thresholds are at TTL levels, and
/ ^. t/ Y- C) w2 Vare therefore compatible with both 3.3-V and 5.0-V inputs.
* d8 j+ F6 X; q3 h$ l( L# \The VCCIO pins can be connected to either a 3.3-V or a 5.0-V power2 J/ _# e- @9 Z9 J8 s% r! _: {
supply, depending on the output requirements. When the VCCIO pins are- b9 a7 X2 B) D
connected to a 5.0-V supply, the output levels are compatible with 5.0-V- l2 `' I4 B8 S: T$ r" [
systems. When VCCIO is connected to a 3.3-V supply, the output high is
1 s; Q! S$ ] G! y$ n' L3.3 V and is therefore compatible with 3.3-V or 5.0-V systems. Devices% K% \; M- a' E- }$ O9 S* r' M
operating with VCCIO levels lower than 4.75 V incur a nominally greater
8 x, W6 k6 \6 L7 Qtiming 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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