Dynamic Power Control¶

Description¶

Change power mode dynamically from task code

This resource allows the Sensor Controller to switch between the active and low-power power modes within task code blocks.

This can be used instead of, or in combination with, static configuration in the Power and Clock Settings Panel in Sensor Controller Studio.

The table below shows clock rate and availability in the different power modes for each task resource:

Task Resource	Clock Rate	Active Mode	Low-Power Mode	Standby Mode
Accumulator Based Math	Same as Sensor Controller	Available	Available
ADC	Same as AUX bus	Available
COMPA	Analog / asynchronous	Available	Available	Available
COMPB	32 kHz	Available	Available*	Available
Delay Insertion	2 MHz	Available	Available
Digital GPIO	Same as Sensor Controller	Available	Available
ISRC	Analog / asynchronous	Available
Reference DAC	Automatically adapted	Available	Available	Available
Pulse Counter	Asynchronous	Available	Available	Available
I2C Master	Same as Sensor Controller	Available
SPI Chip Select	Same as Sensor Controller	Available	Available
SPI Data Transfer	Same as Sensor Controller	Available	Available
TDC	Same as AUX bus	Available
Timer 0	Same as Sensor Controller	Available	Available
Timer 1	Same as Sensor Controller	Available	Available
Timer 2	24 MHz, 2 MHz or 32 kHz	Available	Available	Available
LCD Controller	Same as Sensor Controller	Available	Available	Between updates
UART Emulator	Based on Timer 0	Available
COMPA Event Trigger	Asynchronous			Wake-up trigger
COMPB Event Trigger	Asynchronous (32 kHz)			Wake-up trigger
GPIO Event Trigger	Asynchronous			Wake-up trigger
System Event Trigger	Asynchronous			Wake-up trigger
Timer 0 Event Trigger	4 kHz signal from RTC			Wake-up trigger
Timer 1 Event Trigger	4 kHz signal from RTC			Wake-up trigger
Timer 2 Event Trigger	Based on Timer 2			Wake-up trigger

* The procedures that enable/disable COMPB can only be called when the Sensor Controller (or System CPU) is in active mode.

Examples¶

Entering Active Mode Only During Some Wakeups¶

// The task code block starts in low-power mode

// If some condition is met ...
if (...) {

    // Enter active mode
    pwrRequestAndWaitForActiveMode();

    // Get one ADC sample
    adcEnableSync(ADC_REF_FIXED, ADC_SAMPLE_TIME_2P7_US, ADC_TRIGGER_MANUAL);
    adcGenManualTrigger();
    adcReadFifo(output.adcValue);
    adcDisable();

    // Return to low-power mode
    pwrRequestAndWaitForLowPowerMode();
}

// The task code block ends in low-power mode, so unless changed by the static configuration,
// the Sensor Controller will start in low-power mode at the next wake-up

Procedures Overview¶

Name	Brief description
`pwrRequestActiveMode()`	Requests change to the active power mode. More …
`pwrRequestAndWaitForActiveMode()`	Requests change to the active power mode, and waits for it to take effect. More …
`pwrRequestAndWaitForLowPowerMode()`	Requests change to the low-power power mode, and waits for it to take effect. More …
`pwrRequestLowPowerMode()`	Requests change to the low-power power mode. More …
`pwrWaitForActiveMode()`	Waits for change to the active power mode to take effect. More …
`pwrWaitForLowPowerMode()`	Waits for change to the low-power power mode to take effect. More …

Constants¶

None.

Global Variables¶

None.

Procedures¶

pwrRequestActiveMode¶

Prototype: pwrRequestActiveMode()

Requests change to the active power mode.

This request must be followed by a call to pwrWaitForActiveMode() before:

Calling any other other dynamic power control procedures
The end of the task code block

pwrRequestAndWaitForActiveMode¶

Prototype: pwrRequestAndWaitForActiveMode()

Requests change to the active power mode, and waits for it to take effect.

pwrRequestAndWaitForLowPowerMode¶

Prototype: pwrRequestAndWaitForLowPowerMode()

Requests change to the low-power power mode, and waits for it to take effect.

pwrRequestLowPowerMode¶

Prototype: pwrRequestLowPowerMode()

Requests change to the low-power power mode.

This request must be followed by a call to pwrWaitForLowPowerMode() before:

Calling any other other dynamic power control procedures
The end of the task code block

pwrWaitForActiveMode¶

Prototype: pwrWaitForActiveMode()

Waits for change to the active power mode to take effect.

Note: Deadlock will occur if this procedure is called without a prior call to pwrRequestActiveMode() .

pwrWaitForLowPowerMode¶

Prototype: pwrWaitForLowPowerMode()

Waits for change to the low-power power mode to take effect.

Note: Deadlock will occur if this procedure is called without a prior call to pwrRequestLowPowerMode() .