Roman Haefeli wrote:
On Wed, 2010-06-30 at 14:12 +0200, Ingo Scherzinger wrote:
Hi Roman,
this solution is working also. So in this case it's not really necessary to change the firmata itself. Anyway, I would prefer to have this behaviour as the default behaviour, i.e. included in firmata. At least all of this this should be documented.
Actually, it is here: http://www.arduino.cc/en/Tutorial/DigitalPins
It's not firmata exposing this functionality, but the arduino. So I
And shining through that is the actual microcontroller. It's useful to read the data sheet to see what is possible: http://www.atmel.com/dyn/resources/prod_documents/doc8271.pdf
think it's correct that Firmata handles it transparently, so that from Pd you are still able to decide yourself, whether you actually want that pull-up resistor or not.
Enabling it per default is _not_ a good idea, since there are many applications, where you deliberately want the pull-up resistor not to be enabled. Imagine a sensor with a very high impedance (for instance, an LDR in series with a fixed 1 MOhm resistor), with the pull-up resistor activated the input would always be HIGH, because the internal resistor would brutishly pull the voltage up.
Or if the pin was connected to a relay or something. This is why most of the pins default to high-impedance input after a reset.
Martin