Configure HSPLL
Write 1 to UUPSCTL.USSPWRUP bit
(This can be replaced by a signal internal trigger source if USSPWRUPSEL != 0 )
Configure SAPH
Configure SDHS
Configure UUPS
- UUPSCTL.ASQEN = 0 (ASQ enabled)
- UUPSCTL.USSPWRUPSEL = 0 (USSPWRUP bit is the trigger source)
SDHS Configuration: SDHSCTL0, SDHSCTL1, SDHSCTL2, SDHSCTL6,
SDHSCTL7, SDHSWINHITH,SDHS WINLOTH, and SDHSDTCDA registers.
SDHS Triger Source must be: SDHSCTL0.TRGSRC = 1
Write 1 to SDHSCTL3.TRIGEN bit
1) USS LDO is powered up
2) HSPLL is powered up and locked => UUPSCTL.UPSTATE =3
3) PSQ asserts PSQ_START
4) ASQ generates control signals to PPG and SDHS
- PPG completes generating pulses
- SDHS completes data conversion (ASQ controls SDHS via ASQ_ACQARM and ASQ_ACQTRIG)
5) SDHS asserts SDHS_ACQDONE
6) ASQ asserts ASQ_ACQDONE and asserts SEQDN interrupt
7) PSQ is ready to take a new USSPWRREQ signal
PUC
Next Measurement
LPM Mode and Wake up
(Optional)
Device Initialization
(Optional)
SDHS Functional Operation
584
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
Sigma-Delta High Speed (SDHS)
Figure 22-18. SDHS Operation as Part of USS Measurement (SDHSCTL0.TRGSRC = 1)
22.2.7 TRIGEN Bit and SDHS_LOCK Bit
SDHSCTL3.TRIGEN has two functional roles:
•
The first role is to enable the SDHS to receive the power trigger and conversion trigger signals (see
). SDHSCTL3.TRIGEN must be set to 1 before applying the trigger signals to the SDHS.
•
The second role is to lock the SDHSCTL0, SDHSCTL1, SDHSCTL2, SDHSCTL7, SDHSWINHITH,
SDHSWINLOTH, and SDHSDTCDA registers.
When SDHSCTL3.TRIGEN = 1, those registers cannot be modified. Thus, SDHSCTL3.TRIGEN must be
set to 1 after updating the SDHS registers (except SDHSCTL3, SDHSCTL4, and SDHSCTL5) and before
powering up the SDHS. See
for an example of the SDHS register configuration
sequence. SDHSCTL3.TRIGEN can be used as the power-up trigger signal (see
and
). However, this is not recommended when SDHSCTL0.AUTOSSDIS = 1, because the SDHS
may not be fully settled before data conversion starts.