Datasheet

Start
Sampling
Stop
Sampling
Conversion
Complete
SAMPCON
SHI
t
sample
t
convert
t
sync
13 x ADC12CLK
Start
Conversion
ADC12CLK
Start
Sampling
Stop
Sampling
Conversion
Complete
SAMPCON
SHI
t
sample
t
convert
t
sync
13 x ADC12CLK
Start
Conversion
ADC12CLK
ADC12 Operation www.ti.com
23.2.4.1 Extended Sample Mode
The extended sample mode is selected when SHP = 0. The SHI signal directly controls SAMPCON and
defines the length of the sample period t
sample
. When SAMPCON is high, sampling is active. The high-to-
low SAMPCON transition starts the conversion after synchronization with ADC12CLK (see Figure 23-3).
Figure 23-3. Extended Sample Mode
23.2.4.2 Pulse Sample Mode
The pulse sample mode is selected when SHP = 1. The SHI signal is used to trigger the sampling timer.
The SHT0x and SHT1x bits in ADC12CTL0 control the interval of the sampling timer that defines the
SAMPCON sample period t
sample
. The sampling timer keeps SAMPCON high after synchronization with
AD12CLK for a programmed interval t
sample
. The total sampling time is t
sample
plus t
sync
(see Figure 23-4).
The SHTx bits select the sampling time in 4x multiples of ADC12CLK. SHT0x selects the sampling time
for ADC12MCTL0 to 7 and SHT1x selects the sampling time for ADC12MCTL8 to 15.
Figure 23-4. Pulse Sample Mode
564
ADC12 SLAU144J–December 2004–Revised July 2013
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