[En-Nut-Discussion] Ethernut 5.0 Schematic Preview

[Harald Kipp]

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.


> The problem is that these chips only provide 6V for RS232, that is 
> really low and will surely cause problems. And it is outside specs too.

There are drivers available, which do provide compliant RS232 levels out 
of a 3.3V supply. However, we found out, that they are also somewhat 
more sensitive to shortcuts. Not sure, if they are available with more 
than 2 transmitters.

Harald