Principles for Low
-
Power Applications
2-16
System Resets, Interrupts, and Operating Modes
2.4
Principles for Low
-
Power Applications
Often, the most important factor for reducing power consumption is using the
MSP430’s clock system to maximize the time in LPM3. LPM3 power
consumption is less than 2
μ
A typical with both a real-time clock function and
all interrupts active. A 32-kHz watch crystal is used for the ACLK and the CPU
is clocked from the DCO (normally off) which has a 6-
μ
s wake-up.
-
Use interrupts to wake the processor and control program flow.
-
Peripherals should be switched on only when needed.
-
Use low-power integrated peripheral modules in place of software driven
functions. For example Timer_A and Timer_B can automatically generate
PWM and capture external timing, with no CPU resources.
-
Calculated branching and fast table look-ups should be used in place of
flag polling and long software calculations.
-
Avoid frequent subroutine and function calls due to overhead.
-
For longer software routines, single-cycle CPU registers should be used.
2.5
Connection of Unused Pins
The correct termination of all unused pins is listed in Table 2−2.
Table 2−2. Connection of Unused Pins
Pin
Potential
Comment
AV
CC
DV
CC
AV
SS
DV
SS
V
REF+
Open
Ve
REF+
DV
SS
V
REF−
/Ve
REF−
DV
SS
XIN
DV
CC
XOUT
Open
XT2IN
DV
SS
43x, 44x. and 46x devices
XT2OUT
Open
43x, 44x, and 46x devices
Px.0 to Px.7
Open
Switched to port function, output direction
RST/NMI
DV
CC
or V
CC
47 k
Ω
pullup with 10nF pull down
R03
DV
SS
COM0
Open
TDO/TDI/TMS/
TCK
Open
Ax (dedicated)
Open
42x devices
Sxx
Open
Содержание MSP430x4xx Family
Страница 1: ...MSP430x4xx Family 2007 Mixed Signal Products User s Guide SLAU056G ...
Страница 2: ......
Страница 6: ...vi ...
Страница 114: ...3 76 RISC 16 Bit CPU ...
Страница 304: ...5 20 FLL Clock Module ...
Страница 340: ...7 8 Supply Voltage Supervisor ...
Страница 348: ...8 8 16 Bit Hardware Multiplier ...
Страница 372: ...9 24 32 Bit Hardware Multiplier ...
Страница 400: ...10 28 DMA Controller ...
Страница 428: ...13 10 Basic Timer1 ...
Страница 466: ...15 24 Timer_A ...
Страница 522: ...17 30 USART Peripheral Interface UART Mode ...
Страница 544: ...18 22 USART Peripheral Interface SPI Mode ...
Страница 672: ...23 12 Comparator_A ...
Страница 692: ...24 20 LCD Controller ...
Страница 746: ...26 28 ADC12 ...