
GPIO Registers
1227
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
General-Purpose Input/Outputs (GPIOs)
17.5.20 GPIOCR Register (Offset = 0x524) [reset = X]
GPIO Commit (GPIOCR)
The GPIOCR register is the commit register. The value of the GPIOCR register determines which bits of
the GPIOAFSEL, GPIOPUR, GPIOPDR, and GPIODEN registers are committed when a write to these
registers is performed. If a bit in the GPIOCR register is cleared, the data being written to the
corresponding bit in the GPIOAFSEL, GPIOPUR, GPIOPDR, or GPIODEN registers cannot be committed
and retains its previous value. If a bit in the GPIOCR register is set, the data being written to the
corresponding bit of the GPIOAFSEL, GPIOPUR, GPIOPDR, or GPIODEN registers is committed to the
register and reflects the new value.
The contents of the GPIOCR register can only be modified if the status in the GPIOLOCK register is
unlocked. Writes to the GPIOCR register are ignored if the status in the GPIOLOCK register is locked.
NOTE:
This register is designed to prevent accidental programming of the registers that control
connectivity to the NMI and JTAG/SWD debug hardware. By initializing the bits of the
GPIOCR register to 0 for the NMI and JTAG/SWD pins (see for pin numbers), the NMI and
JTAG/SWD debug port can only be converted to GPIOs through a deliberate set of writes to
the GPIOLOCK, GPIOCR, and the corresponding registers.
Because this protection is currently only implemented on the NMI and JTAG/SWD pins (see
for pin numbers), all of the other bits in the GPIOCR registers cannot be written with 0x0.
These bits are hardwired to 0x1, ensuring that it is always possible to commit new values to
the GPIOAFSEL, GPIOPUR, GPIOPDR, or GPIODEN register bits of these other pins.
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. These six pins are the only GPIOs that are
protected by the GPIOCR register. Because of this, the register type for the corresponding
GPIO Ports is RW.
The default reset value for the GPIOCR register is 0x000000FF for all GPIO pins, with the
exception of the NMI and JTAG/SWD pins. To ensure that the JTAG and NMI pins are not
accidentally programmed as GPIO pins, these pins default to noncommittable. Because of
this, the default reset value of GPIOCR changes for the corresponding ports.
GPIOCR is shown in
and described in
.
Return to
Figure 17-24. GPIOCR Register
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
RESERVED
CR
R-0x0
X
Table 17-30. GPIOCR Register Field Descriptions
Bit
Field
Type
Reset
Description
31-8
RESERVED
R
0x0
7-0
CR
X
GPIO Commit
0x0 = The corresponding GPIOAFSEL, GPIOPUR, GPIOPDR, or
GPIODEN bits cannot be written.
0x1 = The corresponding GPIOAFSEL, GPIOPUR, GPIOPDR, or
GPIODEN bits can be written.