LM3S600 Datasheet, PDF (229/504 Pages) Bookham, Inc. – Microcontroller

Stellaris^® LM3S600 Microcontroller
On reset, all GPIO pins (except for the five JTAG pins) default to general-purpose input mode
(GPIODIR=0 and GPIOAFSEL=0). Table 7-4 on page 229 shows all possible configurations of the
GPIO pads and the control register settings required to achieve them. Table 7-5 on page 229 shows
how a rising edge interrupt would be configured for pin 2 of a GPIO port.
Table 7-4. GPIO Pad Configuration Examples
Configuration
GPIO Register Bit Value^a
AFSEL DIR
ODR
Digital Input (GPIO)
0
0
0
Digital Output (GPIO)
0
1
0
Open Drain Output
0
1
1
(GPIO)
Open Drain
1
X
1
Input/Output (I²C)
DEN
1
1
1
1
Digital Input (Timer
1
X
0
1
CCP)
Digital Output (Timer
1
X
0
1
PWM)
Digital Input/Output
1
X
0
1
(SSI)
Digital Input/Output
1
X
0
1
(UART)
Analog Input
(Comparator)
0
0
0
0
Digital Output
(Comparator)
1
X
0
1
a. X=Ignored (don’t care bit)
?=Can be either 0 or 1, depending on the configuration
PUR
?
?
X
X
?
?
?
?
0
?
PDR
?
?
X
X
?
?
?
?
0
?
DR2R
X
?
?
?
X
?
?
?
X
?
DR4R
X
?
?
?
X
?
?
?
X
?
DR8R
X
?
?
?
X
?
?
?
X
?
SLR
X
?
?
?
X
?
?
?
X
?
Table 7-5. GPIO Interrupt Configuration Example
Desired
Pin 2 Bit Value^a
Register
Interrupt
Event
7
6
5
4
Trigger
GPIOIS
0=edge
X
X
X
X
1=level
GPIOIBE
0=single
X
X
X
X
edge
1=both
edges
GPIOIEV 0=Low level,
X
X
X
X
or negative
edge
1=High level,
or positive
edge
GPIOIM
0=masked
0
0
0
0
1=not
masked
a. X=Ignored (don’t care bit)
3
X
X
X
0
2
0
0
1
1
1
X
X
X
0
0
X
X
X
0
July 14, 2014
229
Texas Instruments-Production Data