LM3S3749 Datasheet, PDF (398/898 Pages) Texas Instruments – Stellaris® LM3S3749 Microcontroller

General-Purpose Input/Outputs (GPIOs)
Bit/Field
7:0
Name
CR
Type
-
Reset
-
Description
GPIO Commit
On a bit-wise basis, any bit set allows the corresponding GPIOAFSEL,
GPIOPUR, or GPIODEN registers to be written.
Note:
The default register type for the GPIOCR register is RO for
all GPIO pins with the exception of the NMI pin and the four
JTAG/SWD pins (PB7 and PC[3:0]). These five pins are
currently the only GPIOs that are protected by the GPIOCR
register. Because of this, the register type for GPIO Port B7
and GPIO Port C[3:0] is R/W.
The default reset value for the GPIOCR register is
0x0000.00FF for all GPIO pins, with the exception of the NMI
pin and the four JTAG/SWD pins (PB7 and PC[3:0]). To
ensure that the JTAG port is not accidentally programmed as
a GPIO, these four pins default to non-committable. To ensure
that the NMI pin is not accidentally programmed as the
non-maskable interrupt pin, it defaults to non-committable.
Because of this, the default reset value of GPIOCR for GPIO
Port B is 0x0000.007F while the default reset value of
GPIOCR for Port C is 0x0000.00F0.
398
November 17, 2011
Texas Instruments-Production Data