signals are 5-V tolerant and are connected directly to their circuitry (C0-, C0+, C1-, C1+). These
signals are configured by clearing the DEN bit in the GPIO Digital Enable (GPIODEN) register. All
GPIO signals are 5-V tolerant when configured as inputs except for PB0 and PB1, which are limited
to 3.6 V. 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 encoding 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. Table entries that are shaded gray are the default values for the corresponding
GPIO pin.
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
pins shown in the table below. A Power-On-Reset (POR) or asserting RST puts the pins
back to their default state.
Table 9-1. GPIO Pins With Non-Zero Reset Values
GPIOPCTLGPIOPURGPIOPDRGPIODENGPIOAFSELDefault StateGPIO Pins
0x10000UART0PA[1:0]
0x20000SSI0PA[5:2]
0x30000I
2
C0PB[3:2]
0x11011JTAG/SWDPC[3:0]
Table 9-2. GPIO Pins and Alternate Functions (100LQFP)
Digital Function (GPIOPCTL PMCx Bit Field Encoding)
a
Analog
Function
PinIO
1110987654321
--U1RxI2C1SCL------U0Rx-26PA0
--U1TxI2C1SDA------U0Tx-27PA1
-------PWM4--SSI0Clk-28PA2
-------PWM5--SSI0Fss-29PA3
----------SSI0Rx-30PA4
----------SSI0Tx-31PA5
------PWM4PWM0-CCP1I2C1SCL-34PA6
----CCP3-PWM5PWM1-CCP4I2C1SDA-35PA7
------U1Rx--PWM2CCP0-66PB0
------U1TxCCP1-PWM3CCP2-67PB1
------CCP0CCP3-IDX0I2C0SCL-70PB2
-------Fault3-Fault0I2C0SDA-71PB3
----U1RxIDX0-U2Rx---AIN10
C0-
92PB4
----U1TxCCP2-CCP0CCP6CCP5C0oAIN11
C1-
91PB5
-----CCP5IDX0Fault1C0oCCP7CCP1VREFA
C0+
90PB6
-------NMI----89PB7
--------TCK
SWCLK
---80PC0
409July 24, 2012
Texas Instruments-Production Data
Stellaris
®
LM3S6G65 Microcontroller
OBSOLETE: TI has discontinued production of this device.
