[En-Nut-Discussion] Ethernut 5.0 Schematic Preview

[Alain M.]

Harald Kipp escreveu:
> Alain M. wrote:
>> Harald Kipp escreveu:
>>> Alain M. wrote:
>>>> has anyone considerd using the RS232 drivers (ZT3243E or ST3234E in 
>>>> Ethernu5) powred by 5V? It should accept 3.3V as level high without any 
>>>> problem, and the ARM9 (most uP) is 5V compliant...
>>> The maximum voltage on all input pins is VDDIO+0.3V or 4V.
>> ST's is clearly specified at 6V. And the Input logic threshold high is 
>> 2.4V with VCC = 5 V
> 
> No problem with the driver, but the ARM9 will die.

:) level shift needed, but only RX has to be fast, all others are slow 
and can be implemented with a simple divider network

It is a nice idea, may be worth for some projects. But I agree that for 
someting like Ethernut that needs universal acceptence, it is not 
advisable :)

Alain

> 
> Harald
> 
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