UG-1262
Rev. B | Page 28 of 312
Wake-Up Sequence
The digital die wake-up mechanism is different for each power-down mode. The wakeup is triggered by an interrupt or a reset. The
sequence for the wakeup is different depending on the power mode. If the wakeup is triggered by a coming interrupt, the system first
executes the interrupt routine.
The analog die exits hibernate mode when the digital die tries to read or write to any analog die register. When the Arm Cortex-M3
executes an instruction to access any analog die register when the analog die is in hibernate mode, the CPU halts until that instruction is
complete. The CPU must wait for the analog die to complete its wake-up sequence before resuming.
The user must reset the ALLON PWRMOD register to active mode after the wake-up sequence is complete. This reset ensures that the
analog die exits hibernate mode correctly when required in the user application.
This following code example shows how to wake up the analog die after the digital die has exited hibernate mode:
uiDummyRead = pADI_AFE->LPDACCON0; // read any analog die register to wake-up analog die
AfePwrCfg(AFE_ACTIVE); // reset pADI_ALLON->PWRMOD[1:0] = 0b01
The ADC reference requires 110 μs to settle after the analog die exits hibernate mode. Do not start any ADC conversions until this
period has elapsed.
MONITOR VOLTAGE CONTROL
The user code must monitor the chip power supply voltages. The AFE die peripherals are not specified to operate at voltages <2.8 V. The
provides a number of features to help user code monitor the AVDD and DVDD supply rails of the
On the digital die, voltage supervisory circuits are enabled at all times to guarantee that the AVDD_DD supply (2.8 V to 3.6 V) and the
regulated supply are always within operating levels. The circuit monitoring these supplies is called the PMU.
The main features for the PMU circuit during active mode are as follows:
Monitors DVDD voltage. Generates a reset to the chip if AVDD_DD supply is below 1.6 V. The analog die generates a reset at a
higher voltage. Refer to the
data sheet specifications for details.
Monitors the state of the AVDD_DD. Generates AVDD_DD power supply monitor (PSM) interrupts between 3.6 V and 2.75 V,
and AVDD_DD PSM interrupts between 2.75 V and 2.3 V. These ranges of interrupts are enabled by the PMG0 IEN register.
Monitors regulated supply.
Generates an interrupt if the DVDD_REG regulated supply is greater than 1.32 V (overvoltage).
Generates an interrupt if the DVDD_REG regulated supply is less than 1.1 V (undervoltage).
Generates a reset if the DVDD_REG regulated supply is below 1.08 V.
The main features for the PMU during hibernate mode are as follows:
Monitors battery voltage.
Generates an alarm to the processor if the supply voltage is less than 1.83 V (optional).
Generates a reset to the chip if the supply is less than 1.6 V (optional).
Monitors the state of the optional battery monitor feature. The PMU also provides optional battery monitoring between 3.6 V
and 2.75 V, and battery between 2.75 V and 2.3 V.
Monitors regulated supply. Generates a reset if the DVDD_REG regulated supply is below 1.08 V.
On the analog die, the ADC input mux on the analog die allows the user to measure a number of the input and regulated supply pins.
These channels include the following:
AVDD supply to the analog die.
DVDD supply to the AFE and digital die.
AVDD_REG regulated 1.8 V analog supply voltage.
The analog die has its own POR circuit that generates a full chip reset if the supply voltage drops below its brownout voltage. See the
data sheet for details.