When the Pin Muxing mode is configured for analog or is disabled, all the digitalfunctions on that pin are disabled. This includes the pullup and pulldown enables, outputbuffer enable, input buffer enable, and passive filter enable.The LK bit (bit 15 of Pin Control Register PCRn) allows the configuration for each pin tobe locked until the next system reset. When locked, writes to the lower half of that pincontrol register are ignored, although a bus error is not generated on an attempted write toa locked register.The configuration of each Pin Control register is retained when the PORT module isdisabled.Whenever a pin is configured in any digital pin muxing mode, the input buffer for thatpin is enabled allowing the pin state to be read via the corresponding GPIO Port DataInput Register (GPIO_PDIR) or allowing a pin interrupt or DMA request to be generated.If a pin is ever floating when its input buffer is enabled, then this can cause an increase inpower consumption and must be avoided. A pin can be floating due to an input pin that isnot connected or an output pin that has tri-stated (output buffer is disabled).Enabling the internal pull resistor (or implementing an external pull resistor) will ensure apin does not float when its input buffer is enabled; note that the internal pull resistor isautomatically disabled whenever the output buffer is enabled allowing the Pull Enable bitto remain set. Configuring the Pin Muxing mode to disabled or analog will disable thepin’s input buffer and results in the lowest power consumption.11.6.2 Global pin controlThe two global pin control registers allow a single register write to update the lower halfof the pin control register on up to 16 pins, all with the same value. Registers that arelocked cannot be written using the global pin control registers.The global pin control registers are designed to enable software to quickly configuremultiple pins within the one port for the same peripheral function. However, the interruptfunctions cannot be configured using the global pin control registers.The global pin control registers are write-only registers, that always read as 0.11.6.3 External interruptsThe external interrupt capability of the PORT module is available in all digital pinmuxing modes provided the PORT module is enabled.Chapter 11 Port Control and Interrupts (PORT)K22F Sub-Family Reference Manual, Rev. 4, 08/2016NXP Semiconductors 255
