# Internal Pullup Sufficient for i2c in beaglebone Black?

I plan to use P8.13 and P8.15 of the beaglebone in a i2c bitbang mode. Do i need to use external pull up resistors in my circuit? or can i use the internal pull up which is available on the beaglebone black itself?

Generally, the smaller the pull-up resistor, the faster is the rise of the signal to 1, but when driving a 0, there is also higher consumption. To understand this better, think about the extremes; what would be the behavior if the pull-up resistor is 0? How about infinite?