SVS Operation
7-5
Supply Voltage Supervisor
7.2.3
Changing the VLDx Bits
When the VLDx bits are changed from zero to any non-zero value, there is an
automatic settling delay, t
d(SVSon)
, implemented that allows the SVS circuitry
to settle. The t
d(SVSon)
delay is approximately 50
μ
s. During this delay, the SVS
will not flag a low-voltage condition or reset the device, and the SVSON bit is
cleared. Software can test the SVSON bit to determine when the delay has
elapsed and the SVS is monitoring the voltage properly. Writing to SVSCTL
while SVSON = 0 will abort the SVS automatic settling delay, t
d(SVSon)
, and
switch the SVS to active mode immediately. In doing so, the SVS circuitry
might not be settled, resulting in unpredictable behavior.
When the VLDx bits are changed from any non-zero value to any other
non-zero value, the circuitry requires the time t
settle
to settle. The settling time
t
settle
is a maximum of ~12
μ
s. See the device-specific data sheet. There is no
automatic delay implemented that prevents SVSFG to be set or to prevent a
reset of the device. The recommended flow to switch between levels is shown
in the following code.
; Enable SVS for the first time:
MOV.B
#080h,&SVSCTL
; Level 2.8V, do not cause POR
; ...
; Change SVS level
MOV.B
#000h,&SVSCTL
; Temporarily disable SVS
MOV.B
#018h,&SVSCTL
; Level 1.9V, cause POR
; ...
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 ...