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??

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??

/ m' |; g$ u; `5 w/ a; q% K5 `如果布正確的話....
/ C9 ?( w$ x9 q9 c& l& {* y$ ?, U能麻煩各位幫我做個詳細的解說嗎??

先說聲謝謝~
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9 a% N* l4 u4 }! q+ J9 M3 l9 m" K7 K& E

4 }, U& U. P/ ~& O& n$ L----------以下是DATASHEET針對VCCIO & VCCINT所做的說明------------

4 c- u2 Y. C/ [9 _+ K/ tMultiVolt I/O Interface

MAX 7000 devices—except 44-pin devices—support the MultiVolt I/O
- S/ y& x0 [# }! x3 r2 Xinterface feature, which allows MAX 7000 devices to interface with
2 ]) A4 e( u+ R, P; Z% t+ Esystems 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
. z2 H4 s8 }! ihave one set of VCC pins for internal operation and input buffers
(VCCINT), and another set for I/O output drivers (VCCIO).
& K& _$ C& O3 D' R: xThe VCCINT pins must always be connected to a 5.0-V power supply.
With a 5.0-V VCCINT level, input voltage thresholds are at TTL levels, and
are therefore compatible with both 3.3-V and 5.0-V inputs.
% U7 o, g+ D2 @* Q5 z) BThe 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
/ Z6 [4 i& q# Y5 ^: l+ e9 {/ `systems. When VCCIO is connected to a 3.3-V supply, the output high is
1 L' O* P9 E! }# _; O3.3 V and is therefore compatible with 3.3-V or 5.0-V systems. Devices
5 ^% m, S) D; c' q* r% Eoperating with VCCIO levels lower than 4.75 V incur a nominally greater
1 \4 R; ]( K5 }" z, V6 xtiming delay of tOD2 instead of tOD1.
- V" B5 O3 r+ L0 a( r. U4 ~
[ 本帖最後由 jimcooper 於 2008-11-9 04:21 PM 編輯 ]

sieg70

Vccint跟Vccio, 以及Ground"每根"都要接

addn

您好
VCCINT接5v,則當io pin為輸入時,可接受3.3v,5v的輸入準位
6 N/ L7 U" U3 [* {2 X* S8 qVCCIO接5v/3.3v,則當io pin為輸出時,輸出準位就為5v/3.3v準為位

[ 本帖最後由 addn 於 2008-11-10 10:16 AM 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!
( z+ I6 b, h/ M& @0 l. X5 B% u+ [8 ]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;
% a) n' Q* y. o/ N- ~( {9 q/ W4 h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!