ADC12_B Operation
882
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
ADC12_B
34.2.8.5 Using the Multiple Sample and Convert (ADC12MSC) Bit
To configure the converter to perform successive conversions automatically and as quickly as possible, a
multiple sample and convert function is available. When ADC12MSC = 1, CONSEQx > 0, and the sample
timer is used (pulse sample mode, ADC12SHP = 1), the first rising edge of SHI signal triggers the first
conversion. Successive conversions are triggered automatically as soon as the prior conversion is
completed (if the ADC local reference buffer is used, ADC12VRSEL= 0001, 0011, 0101, 0111, 1001,
1011, 1101, or 1111, there is one clock cycle before the successive conversion is triggered). Additional
SHI triggers are ignored until the sequence is completed in the single-sequence mode, or until the
ADC12ENC bit is toggled in repeat-single-channel or repeated-sequence modes. The function of the
ADC12ENC bit is unchanged when using the ADC12MSC bit.
34.2.8.6 Stopping Conversions
Stopping ADC12_B activity depends on the mode of operation. The recommended ways to stop an active
conversion or conversion sequence are:
•
Reset ADC12ENC in single-channel single-conversion mode to stop a conversion immediately. The
results are unreliable. For correct results, poll the busy bit until it is reset before clearing ADC12ENC.
•
Reset ADC12ENC during repeat-single-channel operation to stop the converter at the end of the
current conversion.
•
Reset ADC12ENC during a sequence or repeat-sequence mode to stop the converter at the end of the
current conversion.
•
Stop any conversion mode immediately by setting the CONSEQx = 0 and resetting the ADC12ENC
and ADC12ON bit. Conversion data are unreliable.
NOTE:
No ADC12EOS bit set for sequence
If no ADC12EOS bit is set and a sequence mode is selected, resetting the ADC12ENC bit
does not stop the sequence. To stop the sequence, first select a single-channel mode and
then reset ADC12ENC.
34.2.9 Operation in LPM3 and LPM4
The ADC remains active in LPM3 if the following are all true:
•
ADC is on (ADC12ON = 1).
•
Conversion is enabled (ADC12ENC = 1).
•
External triggers are selected (ADC12SHSx
≠
0) OR ACLK is ADC12B source clock (ADC12SSELx =
01b).
The ADC remains active in LPM4 if the following are all true:
•
ADC is on (ADC12ON = 1).
•
Conversion is enabled (ADC12ENC = 1).
•
External triggers are selected (ADC12SHSx
≠
0).
34.2.10 Window Comparator
The window comparator allows to monitor analog signals without any CPU interaction. It is enabled for the
desired ADC12MEMx conversion with the ADC12WINC bit in the ADC12MCTLx register. In the following
the window comparator interrupts are listed:
•
The ADC12LO interrupt flag (ADC12LOIFG) is set if the current result of the ADC12_B conversion is
below the low threshold defined in register ADC12LO.
•
The ADC12HI interrupt flag (ADC12HIIFG) is set if the current result of the ADC12_B conversion is
greater than the high threshold defined in the register ADC12HI.
•
The ADC12IN interrupt flag (ADC12INIFG) is set if the current result of the ADC12_B conversion is
greater than the low threshold defined in register ADC12LO and less than the high threshold defined in
ADC12HI.