LM3S2939 Datasheet, PDF (693/749 Pages) Texas Instruments – Stellaris® LM3S2939 Microcontroller

Stellaris^® LM3S2939 Microcontroller
20.3
Connections for Unused Signals
Table 20-9 on page 693 show how to handle signals for functions that are not used in a particular
system implementation for devices that are in a 100-pin LQFP package. Two options are shown in
the table: an acceptable practice and a preferred practice for reduced power consumption and
improved EMC characteristics. If a module is not used in a system, and its inputs are grounded, it
is important that the clock to the module is never enabled by setting the corresponding bit in the
RCGCx register.
Table 20-9. Connections for Unused Signals (100-pin LQFP)
Function
ADC
GPIO
Hibernate
No Connects
System Control
Signal Name
ADC0
ADC1
ADC2
All unused GPIOs
HIB
VBAT
WAKE
XOSC0
XOSC1
NC
OSC0
OSC1
RST
Pin Number
1
2
5
-
51
55
50
52
53
-
48
49
64
Acceptable Practice
NC
Preferred Practice
GNDA
NC
GND
NC
NC
NC
GND
NC
GND
NC
GND
NC
NC
NC
NC
NC
GND
NC
NC
Pull up as shown in Figure Connect through a capacitor to
5-1 on page 174
GND as close to pin as possible
Table 20-10 on page 693 show how to handle signals for functions that are not used in a particular
system implementation for devices that are in a 108-pin BGA package. Two options are shown in
the table: an acceptable practice and a preferred practice for reduced power consumption and
improved EMC characteristics. If a module is not used in a system, and its inputs are grounded, it
is important that the clock to the module is never enabled by setting the corresponding bit in the
RCGCx register.
Table 20-10. Connections for Unused Signals, 108-pin BGA
Function
ADC
GPIO
Hibernate
No Connects
Signal Name
ADC0
ADC1
ADC2
All unused GPIOs
HIB
VBAT
WAKE
XOSC0
XOSC1
NC
Pin Number
B1
A1
B3
-
M12
L12
M10
K11
K12
-
Acceptable Practice
NC
NC
NC
NC
NC
NC
NC
NC
Preferred Practice
GNDA
GND
NC
GND
GND
GND
NC
NC
June 18, 2012
693
Texas Instruments-Production Data