Infineon SCU Power Down Idle 1 User manual

AURIX™ TC2xx Microcontroller Training
V1.0.0
SCU_Power_Down_Idle_1
Power saving in CPU idle mode
Please read the Important Notice and Warnings at the end of this document

Scope of work
CPU0 switches periodically between run mode and idle mode triggered
by STM timer
The Power Management scheme allows activation of power down modes for
each CPU individually in case there are no active tasks to perform and
power consumption needs to be reduced. In this example, the System Timer
periodically generates interrupts (every two seconds). In the Interrupt
Service Routine, the CPU0 is switched between idle mode and run mode.
CPU0 toggles LED D110 during run mode whereas the LED D110 remains
in the last toggling state while CPU0 is idling.
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Introduction
›The Power Management Scheme allows activation of power down
modes so that the system operates with the minimum required power for a
corresponding application state.
›Idle, Sleep or Standby are supported as power consumption modes. The
Idle is specific to each CPU whereas the Sleep and Standby modes
influence the complete system.
›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.
›The STM has the capability to generate interrupts when its count
reaches a predefined compare value.
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Hardware setup
This code example has been
developed for the board
KIT_AURIX_TC297_TFT_BC-Step.
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Implementation
Configuring the system timer to periodically generate interrupts:
›The configuration of the system timer is done through the function
configSystemTimer().
–The system timer immediately runs after PowerUp and needs to be configured.
–Create an instance of the structure IfxStm_Timer_Config,which is initialized
by calling IfxStm_Timer_initConfig(). Then configure the following
components:
–Set the rate in Hz that refers to interrupt events per second.
–Define the priority for the interrupt (range from 0 to 255)
–Define the provider for interrupt service request as CPU0, CPU1, CPU2 or
DMA
–Specify the comparator register that is used to store the compare value to
trigger an event when timer and comparator register match.
–Use the routine IfxStm_Timer_init() together with the instance of structure
IfxStm_Timer_Config to create the g_myTimer handle.
The above functions can be found in the header IfxStm_Timer.h.
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Implementation
Blink the LED D110:
›CPU0 runs within the endless loop in Cpu0_Main.c. Before it starts a toggle cycle, it waits
for approximately 4 million CPU ticks (equals to 0x400000).
›If the CPU0 is set to idle state, the code execution is halted and the CPU clock is disabled.
This stops the toggling of the LED.
Set/Return to/from Idle state:
›The interrupt service routine defined in SCU_Power_Down_Idle.c controls the CPU0, which
alternates between run state and idle state. The static variable setIdle helps to identify the
next state of the CPU0, whether it remains in run state or is set into idle state.
›If the CPU0 is in idle state and the STM interrupt event occurs then the CPU returns to run
state.
›The function IfxStm_Timer_acknowledgeTimerIrq() is used to acknowledge the interrupt
request and set the next compare value for the next interrupt event. The function can be
found in the header IfxStm_Timer.h.
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Run and Test
After code compilation and flashing the device, verify the behavior of the
LED:
›Check if LED D110 (1) is
blinking (equals to Run Mode)
or remains on/off (equals to
Idle Mode).
1
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References
›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
›AURIX™ Development Studio is available online:
›https://www.infineon.com/aurixdevelopmentstudio
›Use the „Import...“ function to get access to more code examples.
›For questions and support, use the AURIX™ Forum:
›https://www.infineonforums.com/forums/13-Aurix-Forum
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IMPORTANT NOTICE
The information given in this document shall in no
event be regarded as a guarantee of conditions or
characteristics (“Beschaffenheitsgarantie”).
With respect to any examples, hints or any typical
values stated herein and/or any information
regarding the application of the product, Infineon
Technologies hereby disclaims any and all
warranties and liabilities of any kind, including
without limitation warranties of non-infringement
of intellectual property rights of any third party.
In addition, any information given in this
document is subject to customer’s compliance
with its obligations stated in this document and
any applicable legal requirements, norms and
standards concerning customer’s products and
any use of the product of Infineon Technologies in
customer’s applications.
The data contained in this document is exclusively
intended for technically trained staff. It is the
responsibility of customer’s technical
departments to evaluate the suitability of the
product for the intended application and the
completeness of the product information given in
this document with respect to such application.
For further information on the product,
technology, delivery terms and conditions and
prices please contact your nearest Infineon
Technologies office (www.infineon.com).
WARNINGS
Due to technical requirements products may
contain dangerous substances. For information
on the types in question please contact your
nearest Infineon Technologies office.
Except as otherwise explicitly approved by
Infineon Technologies in a written document
signed by authorized representatives of Infineon
Technologies, Infineon Technologies’ products
may not be used in any applications where a
failure of the product or any consequences of the
use thereof can reasonably be expected to result
in personal injury.
Edition 2020-01
Published by
Infineon Technologies AG
81726 Munich, Germany
© 2020 Infineon Technologies AG.
All Rights Reserved.
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Document reference
SCU_Power_Down_Idle_1
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