Monday, November 22, 2010

Arduino Wiznet ethernet shield proper reset

 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 )


Rigol DS1052E Oscilloscope

I finally received the RIGOL DS1052E Scope that I ordered on DealExtreme.

The order from DealExtreme is including shipping.
Unfortunately, a substantial delay (totally unrelated with DealExtreme) was caused by the customs import procedures. Italian posts are terrible.

Overall, it took almost two months to receive the device.
But finally I got it, and in one piece. Package was in good state, and the box was well sealed.

Here is a picture of the product along with box contents, from

I have to say that the product quality is very good, and that usability is good too. (apart from the initial shock of having the default menus in chinese, quickly fixed).

The scope is well built, with good quality sturdy plastic chassis, a good color lcd monitor, and good quality knobs.

Furthermore there is a publicly available hack (check here and to actually double the scope frequency bandwidth to 100MHz, actually turning the Rigol DS1052E into the Rigol DS1102E, which has just a difference in firmware.

Here is the spec comparison of the two models, from the site page describing the hack.

Also this Dave Jones videoblog entry on youtube describes the hack, as well as some tricks in updating the most recent firmwares so to avoid problems.

I did not apply the hack to my scope yet, because I have currently no need of a higher speed. I will do it as soon as I will have the need.

Here are some manuals and documents of this product, taken from Rigol Website:
  User guide
  Programming Guide

Marco (@mgua)