Power Saving in Sleep Mode
SCU, power modes, power down, sleep, AURIX, SCU Power Down Sleep 1
Infineon Technologies AG
Infineon-AURIX SCU Power Down Sleep 1 KIT TC397 TFT-Training-v01 00-EN SCU_Power_Down_Sleep_1 for KIT_AURIX_TC397_TFT
Power Saving in Sleep Mode
AURIXTM TC3xx Microcontroller Training V1.0.0
Please read the Important Notice and Warnings at the end of this document
Scope of work
The system is set into sleep mode and it is waken up by the System Timer Module (STM) every 2 seconds.
An STM timer generates an interrupt on the CPU0 every two seconds, switching the AURIXTM device from run mode to sleep mode and vice versa. A GTM timer, responsible for toggling an LED, is then allowed to go into sleep mode, thus stopping the LED from blinking. Two seconds later, the board is switched back into run mode and the LED blinks again.
2020-06-05
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Introduction
> The System Timer (STM) is a free running 64-bit counter which can be used for timing applications requiring both high precision and long period.
> Among other features, the STM has the capability to generate interrupts when its counter reaches a predefined compare value.
> The Generic Timer Module (GTM) is a modular timer unit designed to accommodate many timer applications.
> It has an in-built Timer Output Module (TOM) that can offer 16 independent channels to generate output signals.
> Sleep Mode affects the whole system and may be entered as an unanimous decision of all the CPUs or based on a singular decision of a master CPU based on the configuration of the CPUSEL register. The CLCx.EDIS register bit is cleared for all the peripherals intended to be inactive during sleep mode.
2020-06-05
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3
Hardware setup
This code example has been developed for the board KIT_A2G_TC397_5V_TFT.
2020-06-05
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Implementation
Configuration of the GTM timer:
Configuration of the GTM timer is done inside the function initTom() and consists of several steps:
> Enable the GTM by calling the function IfxGtm_enable(). > Initialize an instance of the structure IfxGtm_Tom_Timer_Config with its default values
through the function IfxGtm_Tom_Timer_initConfig(). > The structure IfxGtm_Tom_Timer_Config allows the setting of multiple parameters in order
to initialize the module, including: tom: to define the used timer timerChannel: to define the used channel clock: to define the used CMU clock base.frequency: to set the timer frequency for blinking the LED base.isrPriority: to set the Interrupt Service Routine priority base.isrProvider: to set the Interrupt Service Routine provider > Enable the FXU clocks by calling the function IfxGtm_Cmu_enableClocks(). > Initialize and activate the TOM with the given configuration through the function IfxGtm_Tom_Timer_init(). > Start the TOM with function IfxGtm_Tom_Timer_run().
The above functions can be found in the iLLD header IfxGtm_Tom_Timer.h.
2020-06-05
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Implementation
Configuration of the STM timer:
Configuration of the STM timer is done inside the function initStm() and consists of several steps:
> An instance of the IfxStm_Timer_Config structure is initialized with default values through the function IfxStm_Timer_initConfig().
> The following parameters of the configuration are modified: base.frequency to define the frequency at which the interrupts are generated base.isrPriority to define the priority of the interrupt generated by the STM on compare match. It can be a value from 0 to 255, with 0 meaning interrupt is disabled and 255 is the highest priority base.isrProvider to define the service provider responsible for handling the interrupt. This can be any of the available CPUs or the DMA
> The configuration is applied to the STM via the function IfxStm_Timer_init() and the timer is started with the function IfxStm_Timer_run().
The above functions can be found in the iLLD header IfxStm_Timer.h.
2020-06-05
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Implementation
Function to switch between run mode and sleep mode:
The function switchMode() enables the microcontroller to switch between run mode and sleep mode every two seconds.
> To go into sleep mode, a few steps are required: Disable the safety endinit and the endinit protections in order to write in protected registers with IfxScuWdt_clearSafetyEndinitInline() and IfxScuWdt_clearCpuEndinit() functions from the iLLD header IfxScuWdt.h Allow the GTM to go into sleep mode and prohibit the STM to go into sleep mode with the EDIS bit of the clock control register Set the CPU0 as CPU master to trigger a power down mode using the CPUSEL bitfield of the Standby and Wake-up Control Register 1 (PMSWCR1) Send a sleep mode request on CPU0 by setting the REQSLP bitfield of the CPU0 Power Management Control and Status Register (PMCSR0) to 0x2 Re-enable the safety endinit and the endinit protections in order to prevent writes to the protected registers with IfxScuWdt_setSafetyEndinitInline() and IfxScuWdt_setCpuEndinit()
The AURIXTM device goes into run mode when a generic interrupt is triggered on the CPU master (CPU0 in this training). When the STM timer generates an interrupt, after two seconds the microcontroller goes into run mode automatically.
2020-06-05
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Implementation
Interrupt Service Routines (ISRs) of the GTM and STM timers
> The GTM TOM ISR implemented in this example contains the following steps: Clear the timer event with the function IfxGtm_Tom_Timer_acknowledgeTimerIrq() to allow another event to be generated Change the LED state by calling the function IfxPort_togglePin()
> The STM ISR implemented in this example contains the following steps: Re-enable interrupts generation with the function IfxCpu_enableInterrupts() as ISR disables it Clear the timer event with the function IfxStm_Timer_acknowledgeTimerIrq() to allow an other event generation Call the switchMode() function to switch between run mode and sleep mode
2020-06-05
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Run and Test
After code compilation and flashing the device, perform the following steps:
> Check LED D107 (1). This LED is blinking during run mode and stops blinking in sleep mode (the two modes are alternating every two seconds).
> When the AURIXTM device goes into sleep mode, the GTM timer responsible for blinking the LED stops and as a result, the LED remains in the last state at which it was in the run mode, either on or off.
Note: In order to observe the behavior, start all cores.
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References
> AURIXTM Development Studio is available online: > https://www.infineon.com/aurixdevelopmentstudio > Use the ,,Import..." function to get access to more code examples.
> More code examples can be found on the GIT repository: > https://github.com/Infineon/AURIX_code_examples
> For additional trainings, visit our webpage: > https://www.infineon.com/aurix-expert-training
> For questions and support, use the AURIXTM Forum: > https://www.infineonforums.com/forums/13-Aurix-Forum
2020-06-05
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Edition 2020-06 Published by Infineon Technologies AG 81726 Munich, Germany
© 2020 Infineon Technologies AG. All Rights Reserved.
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Document reference SCU_Power_Down_Sleep_1 _KIT_TC397_TFT
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