TM4C129CNCPDT Datasheet, PDF (741/1753 Pages) Texas Instruments – Tiva Microcontroller

Tiva^™ TM4C129CNCPDT Microcontroller
8. Program each pad in the port to have either pull-up, pull-down, or open drain functionality through
the GPIOPUR, GPIOPDR, GPIOODR register. Slew rate may also be programmed, if needed,
through the GPIOSLR register.
9. To enable GPIO pins as digital I/Os, set the appropriate DEN bit in the GPIODEN register. To
enable GPIO pins to their analog function (if available), set the GPIOAMSEL bit in the
GPIOAMSEL register.
10. Program the GPIOIS, GPIOIBE, GPIOEV, and GPIOIM registers to configure the type, event,
and mask of the interrupts for each port.
Note: To prevent false interrupts, the following steps should be taken when re-configuring
GPIO edge and interrupt sense registers:
a. Mask the corresponding port by clearing the IME field in the GPIOIM register.
b. Configure the IS field in the GPIOIS register and the IBE field in the GPIOIBE
register.
c. Clear the GPIORIS register.
d. Unmask the port by setting the IME field in the GPIOIM register.
11. Optionally, software can lock the configurations of the NMI and JTAG/SWD pins on the GPIO
port pins, by setting the LOCK bits in the GPIOLOCK register.
When the internal POR signal is asserted and until otherwise configured, all GPIO pins are configured
to be undriven (tristate): GPIOAFSEL=0, GPIODEN=0, GPIOPDR=0, and GPIOPUR=0Table
10-4 on page 741 shows all possible configurations of the GPIO pads and the control register settings
required to achieve them. Table 10-5 on page 742 shows how a rising edge interrupt is configured
for pin 2 of a GPIO port.
Table 10-4. GPIO Pad Configuration Examples
Configuration
GPIO Register Bit Value^a
AFSEL DIR
ODR DEN
PUR
Digital Input
(GPIO)
0
0
0
1
?
Digital Output
(GPIO)
0
1
0
1
?
Open Drain Output 0
1
1
1
X
(GPIO)
Open Drain
Input/Output
(I2CSDA)
1
X
1
1
X
Digital Input/Output 1
X
0
1
X
(I2CSCL)
Digital Input (Timer 1
X
0
1
?
CCP)
Digital Input (QEI) 1
X
0
1
?
Digital Output
(PWM)
1
X
0
1
?
Digital Output
(Timer PWM)
1
X
0
1
?
PDR
?
?
X
X
X
?
?
?
?
DR2R DR4R DR8R DR12R
X
X
X
X
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
?
X
X
X
X
X
X
X
X
?
?
?
?
?
?
?
?
SLR
X
?
?
?
?
X
X
?
?
June 18, 2014
741
Texas Instruments-Production Data