NXP Semiconductors MWCT101 S Series, Reference Manual

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PORTx_DFWR field descriptions
Field Description
31–5
Reserved
This field is reserved.
This read-only field is reserved and always has the value 0.
FILT Filter Length
The digital filter configuration is valid in all digital pin muxing modes. Configures the maximum size of the
glitches, in clock cycles, that the digital filter absorbs for the enabled digital filters. Glitches that are longer
than this register setting will pass through the digital filter, and glitches that are equal to or less than this
register setting are filtered. Changing the filter length must be done only after all filters are disabled.
10.7 Functional description
10.7.1 Pin control
Each port pin has a corresponding Pin Control register, PORT_PCRn, associated with it.
The upper half of the Pin Control register configures the pin's capability to either
interrupt the CPU or request a DMA transfer, on a rising/falling edge or both edges as
well as a logic level occurring on the port pin. It also includes a flag to indicate that an
interrupt has occurred.
The lower half of the Pin Control register configures the following functions for each pin
within the 32-bit port.
• Pullup or pulldown enable
• Drive strength
• Passive input filter enable
• Pin Muxing mode
The functions apply across all digital pin muxing modes and individual peripherals do not
override the configuration in the Pin Control register. For example, if an I
2
C function is
enabled on a pin, that does not override the pullup configuration for that pin.
When the Pin Muxing mode is configured for analog or is disabled, all the digital
functions on that pin are disabled. This includes the pullup and pulldown enables, output
buffer enable, input buffer enable, and passive filter enable.
The LK bit (bit 15 of Pin Control Register PCRn) allows the configuration for each pin to
be locked until the next system reset. When locked, writes to the lower half of that pin
control register are ignored, although a bus error is not generated on an attempted write to
a locked register.
Chapter 10 Port Control and Interrupts (PORT)
MWCT101xS Series Reference Manual, Rev. 3, 07/2019
NXP Semiconductors 179