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
, l7 i) D3 F8 K$ Y3 x! X9 a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??
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( b, W1 H* B" |, q  q5 H' L; n+ }如果布正確的話....
! d4 A# U2 H* w8 y能麻煩各位幫我做個詳細的解說嗎??
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- c4 h/ ~4 h0 B; D$ i9 r先說聲謝謝~
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: s( j% h( T/ B% W+ A! Z4 C6 w----------以下是DATASHEET針對VCCIO & VCCINT所做的說明------------

MultiVolt I/O Interface
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MAX 7000 devices—except 44-pin devices—support the MultiVolt I/O
interface feature, which allows MAX 7000 devices to interface with
( |5 _  T; x4 ~! {: z1 o& Gsystems 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
2 L) \; K$ h. A/ T7 X" ]have one set of VCC pins for internal operation and input buffers
  a" p) w. Y; m9 V4 H/ w, _9 H  i(VCCINT), and another set for I/O output drivers (VCCIO).
3 Y7 ^+ t6 |" {) I) y; \The 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
) m# J- E" j3 Uare 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
; G1 L& E$ V3 L/ csupply, 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
# V$ B( }& R( r- m8 `) g4 H9 Tsystems. 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
3 S+ S" ~7 h6 s; I# n0 r; Joperating with VCCIO levels lower than 4.75 V incur a nominally greater
0 M5 X6 L  Q' e7 n" J& ]/ o8 Ftiming 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 ]

sieg70

Vccint跟Vccio, 以及Ground"每根"都要接

addn

您好
5 Z: z# `: z; MVCCINT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
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[ 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!
4 G- p' E) p4 z( ?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!
9 ?( D8 k% R5 s* j參考參考!