[En-Nut-Discussion] Ethernut 5.0 Schematic Preview

[Alain M.]

Harald Kipp escreveu:
> 
> Roughly about 50% is finished. The reason for publishing the schematics 
> was indeed to receive your comments. Problem reports as well as feature 
> requests are still most welcome.

Ok, here comes:

1) I believe this is a small error: R74 should probably pulled up, to 
"V3.3" sames as IC27, this way an inactive "PMCS\" would disconect IC7 
pin4 from PA0

2) RS232 port:
2.1) RN1 and RN3 should be connected between the conector and the 
capacitors. This way they can have two functions: a) dump oscilations 
due to reflection in the cable, b) protect IC1 from spykes, acting as a 
filter. I believe that in the current position they have no real 
advantage, CMIIAW.
2.2) Capacitors CN1C and CN2A can be too big for high speed 
cominucations. I understand by the naming of the components that this is 
some kind of 4 capacitor pack. IMHO they sholud be smaller and 
removeable, note that chip specifications are for 150pF worst case 
including cable capacitance.
2.3) IC1 code is probably wrong: I cannot find ZT3243, but I found ST3242...
2.4) ST3243E (not ST3243C) have "ESD protection ±8 kV" so IMHO input 
network is not nescessary

More after your feedback on this first part

Alain