Enabling Internal Resistors

Forum 2005-2010 (read only) Hardware Interfacing
1

From the Diecimila description page:

Each of the 14 digital pins on the Diecimila can be used as an input or output. They operate at 5 volts. Each pin can provide or receive a maximum of 40 mA and has an internal pull-up resistor (disconnected by default) of 20-50 kOhms.

I am trying to use the Wire library on pins A4 & A5 - does the Wire library enable these resistors or do I have to do it? If so, how?

Scott

2

If so, how?

digitalWrite( 3, HIGH );
digitalWrite( 4, HIGH );

3

Thanks - that addresses how to enable the resistors, but does the Wire library do this automatically?

4

does the Wire library do this automatically?

I think so, as I just reviewed my code and it doesn't enable them manually, but my circuit has no external pullups for I2C.

-j

5

does the Wire library do this automatically?

I think so, as I just reviewed my code and it doesn't enable them manually, but my circuit has no external pullups for I2C.

-j

Just to confirm, pull-ups are enabled in the twi_init function of the wire library.

6

Great! Thanks a lot.