LM3S817 Datasheet, PDF (230/553 Pages) List of Unclassifed Manufacturers – Microcontroller

General-Purpose Input/Outputs (GPIOs)
7.1 Block Diagram
Figure 7-1. GPIO Module Block Diagram
PA0
U0Rx
UART0
PA1
U0Tx
PA2
SSICLK
PA3
SSIFss
SSI
PA4
SSIRx
PA5
SSITx
PB0
PWM2
PWM1
PB1
PWM3
Fault
PB2
PB3
PB4
C0-
PB5
C0o
Analog
Comparators
PB6
C0+
PB7
JTAG
TCK/SWCLK
PC0
SWD/SWO
TMS/SWDIO
PC1
TDI
PC2
TRST
TDO/SWO
PC3
PC4
PC5
PC6
CCP5 GP Timer 2 CCP4
PC7
Fault
PWM0
PD0
PWM0
PWM1
PD1
UART1
U1Rx
PD2
U1Tx
PD3
CCP1 GP Timer 0 CCP0
PD4
CCP3 GP Timer 1 CCP2
PD5
PWM4
PE0
PWM2
Fault
PWM5
PE1
LM3S817
7.2
Signal Description
GPIO signals have alternate hardware functions. Table 7-3 on page 231 lists the GPIO pins and their
analog and digital alternate functions. The AINx analog signals are not 5-V tolerant and go through
an isolation circuit before reaching their circuitry. These signals are configured by clearing the
corresponding DEN bit in the GPIO Digital Enable (GPIODEN) register. Other analog signals are
5-V tolerant and are connected directly to their circuitry (C0-, C0+). These signals are configured
by clearing the DEN bit in the GPIO Digital Enable (GPIODEN) register. The digital alternate hardware
functions are enabled by setting the appropriate bit in the GPIO Alternate Function Select
(GPIOAFSEL) and GPIODEN registers and configuring the PMCx bit field in the GPIO Port Control
(GPIOPCTL) register to the numeric enoding shown in the table below. Note that each pin must be
programmed individually; no type of grouping is implied by the columns in the table.
Important: All GPIO pins are configured as GPIOs and tri-stated by default (GPIOAFSEL=0,
GPIODEN=0, GPIOPDR=0, GPIOPUR=0, and GPIOPCTL=0, with the exception of the
four JTAG/SWD pins (shown in the table below). A Power-On-Reset (POR) or asserting
RST puts the pins back to their default state.
Table 7-1. GPIO Pins With Non-Zero Reset Values
GPIO Pins
PA[1:0]
Default State
UART0
GPIOAFSEL GPIODEN GPIOPDR GPIOPUR GPIOPCTL
1
1
0
0
0x1
230
July 14, 2014
Texas Instruments-Production Data