Infineon GTM TIM Capture 1 User manual

AURIX™ TC2xx Microcontroller Training
V1.0.0
GTM_TIM_Capture_1
PWM input capturing via TIM
Please read the Important Notice and Warnings at the end of this document

Scope of work
The Timer Input Module (TIM) of the GTM is used to capture an external
PWM signal and calculate the PWM signal frequency and duty cycle.
The TIM is used in capture mode. The data from the captured PWM signal is
used to calculate the PWM signal frequency and duty cycle in software. The
frequency and the duty cycle are then stored in variables.
2
2020-01-17 Copyright © Infineon Technologies AG 2020. All rights reserved.

Introduction
›The Generic Timer Module (GTM) is a modular timer unit designed to
accommodate many timer applications.
›The Timer Input Module (TIM) is responsible for filtering and capturing
input signals of the GTM.
›The Clock Management Unit (CMU) is responsible for clock generation of
the GTM. The Configurable Clock Generation Subunit (CFGU) provides
eight clock sources for the GTM submodules: TIM, TBU, MON and ATOM.
GTM TIM GTM TOM
3
2020-01-17 Copyright © Infineon Technologies AG 2020. All rights reserved.

Introduction
›The GTM has an in-built Timer Output Module (TOM) that can offer 16
independent channels to generate output signals.
›The Clock Management Unit (CMU) is responsible for clock generation of
the GTM. The Fixed Clock Generation (FXU) is one of its subunits and it
provides five predefined non-configurable clocks for GTM modules,
including the TOM.
GTM TOM
GTM TIM
4
2020-01-17 Copyright © Infineon Technologies AG 2020. All rights reserved.

Hardware setup
This code example has been
developed for the board
KIT_AURIX_TC297_TFT_BC-Step.
Connect the TIM input port pin
P02.0 with the TOM output port pin
P02.3.
5
2020-01-17 Copyright © Infineon Technologies AG 2020. All rights reserved.

Implementation
Configuring the TIM
The configuration of the TIM is done by calling the initialization function init_TIM_module(),
containing the following steps:
›Enable the GTM by calling the function IfxGtm_enable()
›Enable the CMU clock 0 by calling the function IfxGtm_Cmu_enableClocks()
›Initialize an instance of the IfxGtm_Tim_In_Config structure with the default parameters by
calling the iLLD function IfxGtm_Tim_In_initConfig()
›The IfxGtm_Tim_In_Config structure allows the setting of multiple parameters in order to
initialize the module, including the following:
–filter.inputPin –Selection of the input port pin of the TIM (port pin P02.0 in this example)
–filter.inputPinMode –Selection of the input mode for the input port pin of the TIM
(IfxPort_InputMode_pulldown in this example)
›After setting the configuration parameters, the function IfxGtm_Tim_In_init() applies the
user configuration to the module
All the functions used for the configuration of the TIM are provided by the iLLD header
IfxGtm_Tim_In.h.
6
2020-01-17 Copyright © Infineon Technologies AG 2020. All rights reserved.

Implementation
Configuring the TOM
The configuration of the TOM is done by calling the function generate_PWM() containing the
following steps:
›Enable the FXU clocks by calling the function IfxGtm_Cmu_enableClocks().
›Initialize an instance of the structure IfxGtm_Tom_Pwm_Config with its default values by
calling the function IfxGtm_Tom_Pwm_initConfig() .
›The IfxGtm_Tom_Pwm_Config structure allows to set the following parameters to initialize
the module:
–tom –Selection of the TOM which is counting
–tomChannel –Selection of the channel which is driving the output port pin
–period –Setting of the period for the PWM signal to the desired value
–dutyCycle –Setting of the duty cycle of the PWM signal to the desired value
–pin.outputPin –Selection of the output port pin
–synchronousUpdateEnable –Enabling of Synchronous Update of the timer
–clock –Selection of the clock used for the generation of the PWM
7
2020-01-17 Copyright © Infineon Technologies AG 2020. All rights reserved.

Implementation
Configuring the TOM
›After setting the configuration parameters, the function IfxGtm_Tom_Pwm_init() applies the
user configuration to the module
›Start the PWM with the function IfxGtm_Tom_Pwm_start()
All the functions used for the configuration of the TOM are provided by the iLLD header
IfxGtm_Tom_Pwm.h.
8
2020-01-17 Copyright © Infineon Technologies AG 2020. All rights reserved.

Implementation
PWM generation example
The FXU clock 1 frequency (ffxclk1) is 6.250 MHz in this example. The period value to have the
desired PWM frequency (fPWM) is calculated with the following formula:
  



In this example:    
       
t
t
PWM signal
Period of PWM
FXU clock 1
Frequency of the
clock
Duty cycle of the PWM
9
2020-01-17 Copyright © Infineon Technologies AG 2020. All rights reserved.

Implementation
Measuring PWM frequency and duty cycle
The measurement of the PWM frequency and duty cycle is done by calling the
function measure_PWM() containing the following steps:
›Update the measured PWM data by calling the iLLD function
IfxGtm_Tim_In_update()
›Get the PWM period in seconds with the iLLD function
IfxGtm_Tim_In_getPeriodSecond()
›Calculate the PWM frequency with the formula: frequency(Hz) = 1 / period(s)
›Get the PWM duty cycle by calling the iLLD function
IfxGtm_Tim_In_getDutyPercent()
All the iLLD functions above are provided by the iLLD header IfxGtm_Tim_In.h
10
2020-01-17 Copyright © Infineon Technologies AG 2020. All rights reserved.

Run and Test
After code compilation and flashing the device, perform the following steps:
›Add the variables g_measuredPwmFreqHz and g_measuredDutyCycle
to the Watch Expressions on the debugger
›Suspend the program to check the value of the variables
11
2020-01-17 Copyright © Infineon Technologies AG 2020. All rights reserved.

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
12
2020-01-17 Copyright © Infineon Technologies AG 2020. All rights reserved.

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.
Do you have a question about this
document?
Email: [e-mail]
Document reference
GTM_TIM_Capture_1
Trademarks
All referenced product or service names and trademarks are the property of their respective owners.