I2C and RESET pushbutton

Created Wed, 01 Jun 2011 18:47:41 +0000 by rade95

rade95

Wed, 01 Jun 2011 18:47:41 +0000

Hi, is I2C on chipKIT boards on analog pins A4 and A5 and is it a 3.3V or a 5V bus?

Is it necessary to press the pushbutton after or during code download, like it was needed on older Arduino boards (NG)?

thanks, Rade95

GeneApperson

Wed, 01 Jun 2011 22:10:44 +0000

In order to multiplex the analog and i2c functions of the pins on the Uno32, I had to use jumpers. The i2c signals will show up on A4 and A5 when jumpers JP6 and JP8 are set appropriately. The i2c signals on the Max32 (like the Mega) are on a different connector and don't need the jumpers

The chipKIT boards don't have i2c pullups on them (like the regular Arduino boards), and so you have to provide the pullups externally. Because of the way the i2c signal thresholds work, mixing 3.3v and 5v on the same bus is problematic. I think that pulling them to 5v would probably work, but I don't think that we've tried it to make sure. It would be better to run the i2c bus at 3.3V

The chipKIT boards are set up to be reset automatically by the IDE when programming, like the newer Arduino boards.

Gene Apperson Digilent

rade95

Thu, 02 Jun 2011 03:59:20 +0000

Thanks Gene, actually I need I2C to operate at 3.3V so your solution is fine. Placing an order now.

deOmair

Sat, 13 Dec 2014 09:44:48 +0000

The i2c signals on the Max32 (like the Mega) are on a different connector and don't need the jumpers...........