[En-Nut-Discussion] lvttl and ttl

[iVesWorking]

so from wat u mean is always better to a bus convertor ic between two off 
the device if the target is ,
which IC you guys normally use (prefer bidirection)?

wfloh.


----- Original Message ----- 
From: "Uwe Bonnes" <bon at elektron.ikp.physik.tu-darmstadt.de>
To: "Ethernut User Chat (English)" <en-nut-discussion at egnite.de>
Sent: Thursday, November 02, 2006 4:47 PM
Subject: Re: [En-Nut-Discussion] lvttl and ttl


>>>>>> "iVesWorking" == iVesWorking  <ivesworking at hotmail.com> writes:
>
>    iVesWorking> my previous design is base on avr which run 5V TTL, but i
>    iVesWorking> looking forward on 3.3V LVTTL Sam7X, but i not sure about
>    iVesWorking> the need on adding a 3.3V to 5V bus convertor, or just
>    iVesWorking> connect as usual, since device mention about their are 5V
>    iVesWorking> tolerance, so i assume using the same connection without
>    iVesWorking> the bus convertor will be fine. is this true?
>
> The SAM is 5 Volt tolerant and can live with Signals coming from 5 V TTL 
> or
> 5 V CMOS. 5 Volt TTL is also perfectly happy with 3.3 Volt CMOS Signals, 
> as
> coming from th SAM7. However 5 Volt CMOS will work (if supposed to work
> together with 5 V TTL), or may work (if the VIH Voltage in the datasheet 
> is
> above 3.3 Volt). 5 Volt CMOS RAM will draw substantial more idel current
> with 3.3 Volt CMOS input voltage, as the input buffers will be somehow 
> cross
> conducting.
>
> So it depends...
> -- 
> Uwe Bonnes                bon at elektron.ikp.physik.tu-darmstadt.de
>
> Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
> --------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------
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