Start
Sampling
Stop
Sampling
Conversion
Complete
SAMPCON
SHI
t
sample
t
convert
t
sync
14 × ADC12CLK
(+1 CLK if ADC12WINC=1)
Start
Conversion
ADC12CLK
+ one clock cycle
If an ADC local reference buffer is used,
user should wait for it to be ready
given by ADC12RDYIFG = 1
t
sync
+
3 ADC12_B source
clock cycles
Start
Sampling
Stop
Sampling
Conversion
Complete
SAMPCON
SHI
t
sample
t
convert
t
sync
14 × ADC12CLK
(+1 CLK if ADC12WINC=1)
Start
Conversion
ADC12CLK
+ one clock cycle
ADC12_B Operation
874
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
ADC12_B
Figure 34-3. Extended Sample Mode Without Internal Reference in 12-Bit Mode
Figure 34-4. Extended Sample Mode With Internal Reference in 12-Bit Mode
34.2.6.2 Pulse Sample Mode
ADC12SHP = 1 selects the pulse sample mode. The SHI signal triggers the sampling timer. The
ADC12SHT0x and ADC12SHT1x bits in ADC12CTL0 control the interval of the sampling timer that defines
the SAMPCON sample period t
sample.
The sampling timer keeps SAMPCON high while waiting for reference
and ADC local reference buffer to settle (if the internal reference is used), synchronization with AD12CLK,
and for the programmed interval t
sample
. The exception is for the first conversion or where ADC12MSC=0
where an extra 3 ADC12_B source clock cycles is required when SAMPCON goes high. (see
and
The ADC12SHTx bits select the sampling time in 4x multiples of ADC12CLK. ADC12SHT1x selects the
sampling time for ADC12MEM8 to ADC12MEM23, and ADC12SHT0x selects the sampling time for
ADC12MEM0 to ADC12MEM7 and ADC12MEM24 to ADC12MEM31.