05-11-2014, 02:18
Having the ability to disable the Arduino Nano auto-reset (using the VP1 switch) is important for the functioning of the WeatherDuino Pro2 receiver, when used in Davis emulation mode.
To disable the auto-reset, I have used a method that consists in connecting a 120 Ohm resistor between the Reset pin and 5V. This method works well for Arduinos Nano with real or fake FTDI chipsets, but as first detected by uncle_bob, this method does not work with Arduinos with the new CH340 chipset.
There are other methods, described in many sites on the internet that work with CH340 chipset, but its application to existing boards or already built systems, would require some changes. To avoid this, I've done some experiments trying to find another solution compatible with existing boards, and I think I found it! It works like a charm on my three test units.
If you are using an Arduino with the CH340 chipset on your WeatherDuino Pro2 receiver, simply replace the R6 resistor (boards v3.01 or lower), with a 0,1uF ceramic capacitor. And that's it! Simple and effective!
To disable the auto-reset, I have used a method that consists in connecting a 120 Ohm resistor between the Reset pin and 5V. This method works well for Arduinos Nano with real or fake FTDI chipsets, but as first detected by uncle_bob, this method does not work with Arduinos with the new CH340 chipset.
There are other methods, described in many sites on the internet that work with CH340 chipset, but its application to existing boards or already built systems, would require some changes. To avoid this, I've done some experiments trying to find another solution compatible with existing boards, and I think I found it! It works like a charm on my three test units.
If you are using an Arduino with the CH340 chipset on your WeatherDuino Pro2 receiver, simply replace the R6 resistor (boards v3.01 or lower), with a 0,1uF ceramic capacitor. And that's it! Simple and effective!