Arduino 2009 Wiznet Ethernet Shield proper reset
(last modified on nov 22 2010)
Problem: Arduino 2009 with wiznet w5100 ethernet shield does not start network operations after power-up.
It works well if the reset button is pressed.
Solution: I implemented davekw7x's suggestions (THANK YOU!), as cited in this arduino forum page (ref. reply #11)
this solution requires a 10kOhm resistor, and a 10nf capacitor.
Here are the detailed steps and some pictures:
1. bend outwards the ethernet shield reset pin "leg", so that it will not go in the arduino reset socket.
2. solder the 10kOhm resistor between reset pin and the nearby 3.3 Vcc
3. solder the 10nf capacitor between reset pin and ground
Here is a picture of one of my ethernet shields, with the reset "leg" bent outwards.
And this is the details of how I soldered the components on the back of the circuit.
In this position the components are nicely arranged on the back of the board.
With this mod, my arduino + ethernet shield is starting up correctly after powering up, and immediately works with no need of reset button push.
Marco ( @mgua )