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??
, P5 ~0 E( c: A
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.....
- k+ k$ V$ R/ _" O5 r我的想法正確嗎??
7 n  o1 h! |9 k, y; r
如果布正確的話....
& d; {( W9 F: A7 l能麻煩各位幫我做個詳細的解說嗎??

先說聲謝謝~


/ N) x: b, K6 s/ A
----------以下是DATASHEET針對VCCIO & VCCINT所做的說明------------

7 w7 V% B9 G  A2 U+ LMultiVolt I/O Interface
. @6 d1 q' v% t1 _$ w7 h! J
MAX 7000 devices—except 44-pin devices—support the MultiVolt I/O
interface feature, which allows MAX 7000 devices to interface with
) ~& x* J' z. l0 k: U1 R( O8 Wsystems 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
9 I( f% s9 J  Q) Ghave one set of VCC pins for internal operation and input buffers
(VCCINT), and another set for I/O output drivers (VCCIO).
/ J1 z6 R9 g  {The VCCINT pins must always be connected to a 5.0-V power supply.
3 \; ]/ H& q1 R+ ~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.
+ Z; ?) s2 H$ P5 ]The VCCIO pins can be connected to either a 3.3-V or a 5.0-V power
8 U: v* R1 D7 A. h  B! g% M& p- Esupply, 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
3.3 V and is therefore compatible with 3.3-V or 5.0-V systems. Devices
4 u- y/ B: I, c7 I4 m* l$ T# R  _! toperating with VCCIO levels lower than 4.75 V incur a nominally greater
timing delay of tOD2 instead of tOD1.

- G2 F: z  ^4 u. T$ _* U# g[ 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
5 f( F8 N" w, Q* AVCCIO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!
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!