The DLPC4430 controller provides 83 software-programmable, general-purpose I/O pins. Each GPIO pin is individually configurable as either input or output. In addition, each GPIO output can be either configured as push-pull or open-drain. Some GPIO have one or more alternate-use modes, which are also software configurable. The reset default for all GPIO is as an input signal. However, any alternate function connected to these GPIO pins, with the exception of general purpose clocks and PWM generation, stay in reset. When configured as open-drain, the outputs must be externally pulled-up (to the 3.3-V supply). External pull-up or pulldown resistors may be required to ensure stable operation before software is able to configure these ports.