TM4C1294NCZAD Datasheet, PDF (791/1914 Pages) Texas Instruments – Tiva Microcontroller

Tiva^™ TM4C1294NCZAD Microcontroller
Register 20: GPIO Commit (GPIOCR), offset 0x524
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.
Important: 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 “Signal Tables” on page 1782
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 “Signal Tables” on page 1782 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.
GPIO Commit (GPIOCR)
GPIO Port A (AHB) base: 0x4005.8000
GPIO Port B (AHB) base: 0x4005.9000
GPIO Port C (AHB) base: 0x4005.A000
GPIO Port D (AHB) base: 0x4005.B000
GPIO Port E (AHB) base: 0x4005.C000
GPIO Port F (AHB) base: 0x4005.D000
GPIO Port G (AHB) base: 0x4005.E000
GPIO Port H (AHB) base: 0x4005.F000
GPIO Port J (AHB) base: 0x4006.0000
GPIO Port K (AHB) base: 0x4006.1000
GPIO Port L (AHB) base: 0x4006.2000
GPIO Port M (AHB) base: 0x4006.3000
GPIO Port N (AHB) base: 0x4006.4000
GPIO Port P (AHB) base: 0x4006.5000
GPIO Port Q (AHB) base: 0x4006.6000
GPIO Port R (AHB) base: 0x4006.7000
GPIO Port S (AHB) base: 0x4006.8000
GPIO Port T (AHB) base: 0x4006.9000
Offset 0x524
Type -, reset -
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
reserved
Type RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
reserved
CR
Type RO
RO
RO
RO
RO
RO
RO
RO
-
-
-
-
-
-
-
-
Reset
0
0
0
0
0
0
0
0
-
-
-
-
-
-
-
-
June 18, 2014
791
Texas Instruments-Production Data