Operational Information
1386
SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
Inter-Integrated Circuit (I2C) Module
27.5.5 Pull Up/Pull Down Function
I2C module pins can have either an active pull up or active pull down that makes it possible to leave the
pins unconnected externally. The pins can be programmed to have the active pull function enabled or
disabled by writing to the corresponding bit in the I2CPDIS register. Please see the device-specific data
sheet for the default internal pull (pull-up, pull-down or no pull) on the pins.
The pull on the pins is programmable to a setting other than the default internal pull as specified in the
data sheet. The pins can be programmed to have either an active pull up or an active pull down function
by writing to the corresponding bit in I2CPSEL register. The pull up/pull down function is active on the pin
only when the pull enabled is programmed in the I2CPDIS register.
The pull up/pull down functions are deactivated when a bidirectional pin is configured as an output. At
system reset, the pull up function of all the pins is enabled. Please see the device-specific data sheet for
the current supplied by the pull up/pull down.
27.5.6 Open Drain Function
The I2C pins can be programmed to include an open drain function when they are configured as output
pins. This is done by writing to the corresponding bit of the I2CPDR register. When the open drain function
is enabled, a low value (0) written to the data output register forces the pin to a low output voltage (V
OL
or
lower), whereas a high value (1) written to the data output register forces the pin to a high-impedance
state. The open drain function is disabled when the pin is configured as an input pin.