SDHSCTL0.AUTOSSDIS = 0, SDHSCTL2.SMPCTLOFF = 1
SDHSCTL4.SDHSON or
ASQ_ACQARM
SDHSCTL5.SDHS_LOCK bit
(Read Only)
SDHS is Power Off
SDHS Settling Time
Conversion Start
First Sample
Conversion
Stop
Last
Sample
Sample
Sample
SDHS Power Off
ACQDONE Interrupt
SSTRG Interrupt
Conversion
Conversion
Conversion
SDHS Functional Operation
588
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
Sigma-Delta High Speed (SDHS)
22.2.8 AUTOSSDIS (Auto Conversion Start Disable) Bit
The SDHS supports two different ways to start data conversion after power up (see
Table 22-7. Conversion Control Mode
Mode
Control
Power up SDHS
Conversion Start
Operation
SDHSCTL0.AU
TOSSDIS
When
SDHSCTL0.TR
GSRC = 0
When
SDHSCTL0.TR
GSRC = 1
When
SDHSCTL0.TR
GSRC = 0
When
SDHSCTL0.TR
GSRC = 1
Auto
conversion
start: disabled
1
SDHSCTL4.SD
HSON = 1
ASQ_ACQARM
= 1 (from ASQ)
SDHSCTL5.SS
TART = 1
ASQ_ACQTRG
= 1 (from ASQ)
Power up and
conversion start are
controlled separately.
The SDHS settling time
must be satisfied before
asserting the conversion
start signal.
Auto
conversion
start: enabled
0
SDHSCTL4.SD
HSON = 1
ASQ_ACQARM
= 1 (from ASQ)
Not Required
Not Required
Data conversion
automatically begins
after power up. The
SDHS settling time is
automatically applied.
When SDHSCTL0.AUTOSSDIS = 0, automatic conversion start is enabled. Conversion automatically
starts after the SDHS is powered on. During power up, the SDHS settling time is monitored and when the
SDHS is settled, conversion automatically begins. See
for the sequence of conversion start
and stop in this mode.
When SDHSCTL0.AUTOSSDIS = 1, auto conversion start is disabled (default after reset). In this mode,
power control and conversion control are separate (see
). This mode can be used when data
conversion start time needs to be precisely controlled. It is important that the SDHS settling time must has
satisfied before data conversion start signal is applied. If the data conversion start trigger signal is applied
during the settling time, the SDHS data conversion is automatically delayed until the settling time has
passed. SDHS settling time is The greater of the PGA settling time and SDHS modulator settling time.
See the device-specific data sheet for the settling times.
Figure 22-21. Conversion Start and Stop When SDHSCTL0.AUTOSSDIS = 0