初學者一問......有關EPM7128S......VCCINT & VCCIO的問題

jimcooper

請問一下VCCINT & VCCIO還有其對應的GND 這些腳位是做甚麼用的啊??

( p4 o0 p; K: n! L. v- r8 j% ?我已經看我DATASHEET上對這方面的說明,但感覺還是有點不清楚
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.....
我的想法正確嗎??
( d0 g1 Z! _5 _8 t5 g9 f
: O- o; k5 i$ O( T& R* ?5 `如果布正確的話....
能麻煩各位幫我做個詳細的解說嗎??
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先說聲謝謝~

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; {( h, H; Z6 r4 f----------以下是DATASHEET針對VCCIO & VCCINT所做的說明------------

& k2 X" y8 _7 x* wMultiVolt I/O Interface
6 \5 e( B% X3 j1 Q3 N: f
9 @3 J1 v& `% h" ^MAX 7000 devices—except 44-pin devices—support the MultiVolt I/O
interface feature, which allows MAX 7000 devices to interface with
systems that have differing supply voltages. The 5.0-V devices in all
packages can be set for 3.3-V or 5.0-V I/O pin operation. These devices
5 O6 O+ L8 J" u: o& P: b1 Whave one set of VCC pins for internal operation and input buffers
0 r/ J' ^& G* J, r1 H7 y+ g(VCCINT), and another set for I/O output drivers (VCCIO).
The VCCINT pins must always be connected to a 5.0-V power supply.
  ?1 v3 A) i9 h) j* `% \With a 5.0-V VCCINT level, input voltage thresholds are at TTL levels, and
( N; l2 I0 J, x1 b6 V! N* s4 Yare therefore compatible with both 3.3-V and 5.0-V inputs.
The VCCIO pins can be connected to either a 3.3-V or a 5.0-V power
supply, depending on the output requirements. When the VCCIO pins are
connected to a 5.0-V supply, the output levels are compatible with 5.0-V
systems. When VCCIO is connected to a 3.3-V supply, the output high is
8 v7 w0 c+ l: n" |% [3.3 V and is therefore compatible with 3.3-V or 5.0-V systems. Devices
operating with VCCIO levels lower than 4.75 V incur a nominally greater
timing delay of tOD2 instead of tOD1.
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8 ]1 r# e7 @+ A5 X6 N* v2 m2 V[ 本帖最後由 jimcooper 於 2008-11-9 04:21 PM 編輯 ]

ssejack1

VCCIO 在有些產品有分 block, 當不同 IO 電壓要使用在同一顆 IC 時可以劃分在不同的 block 就可同時使用不同之IO 準位; VCCINT 為 IC core 電壓,與 user 較沒直接關係,只要依 spec. 供給就沒有問題!
5 f' L% t' a2 ?1 F0 ]! a* m1 H須注意的是 VCCINT 與 VCCIO 有點影響,越低的 VCCINT 製程越新, delay / speed 多比較快,壞處是 VCCIO 會較低;
比如 VCCINT = 3.3V者, VCCIO 一般 3.3/5.0 均可,但 VCCINT = 2.5者 VCCIO 或許無法始用 5.0 v 了!
參考參考!

addn

您好
9 [! \" ~9 G5 n* j* h0 }* B5 [VCCINT接5v,則當io pin為輸入時,可接受3.3v,5v的輸入準位
VCCIO接5v/3.3v,則當io pin為輸出時,輸出準位就為5v/3.3v準為位

2 @/ a4 a3 \9 s  }( h9 `[ 本帖最後由 addn 於 2008-11-10 10:16 AM 編輯 ]

sieg70

Vccint跟Vccio, 以及Ground"每根"都要接