4.20. PWM Module
4.20.1. Acronyms and Definitions
Abbreviation/Term |
Explanation |
|---|---|
AUTOSAR |
Automotive Open System Architecture |
BSW |
Basic Software |
DET |
Default Error Tracer |
HW |
Hardware |
SW |
Software |
PWM |
Pulse Width Modulation |
MCU |
Micro Controller Unit |
OS |
Operating System |
PLL |
Phase Locked loop |
Definitions |
Descriptions |
|---|---|
PWM Channel |
Numeric identifier linked to a hardware PWM. |
PWM period |
Defines the period of the PWM signal. |
PWM Duty cycle |
Defines a percentage of the starting level (could be high or low) related to the period. |
PWM Idle State |
The idle state represents the output state of the PWM channel after the call of Pwm_SetOutputToIdle or Pwm_DeInit. |
PWM Output State |
Defines the output state for a PWM signal. It could be High or Low. |
4.20.2. Introduction
This document describes the functionality and configuration of the AUTOSAR BSW module PWM.
Supported AUTOSAR Release |
4.3.1 |
|---|---|
Supported Configuration Variants |
Pre-Compile, Post-build |
Vendor ID |
PWM_VENDOR_ID (44) |
Module ID |
PWM_MODULE_ID (121) |
Supported Platform |
AM263x |
The PWM driver provides functions for initialization and control of the microcontroller internal PWM stage (pulse width modulation).
4.20.3. Functional Overview
The PWM driver depends on other modules like DET for error handling, OSEK/AUTOSAR OS for interrupt handling, MCU module for system clock settings and SchM module which is BSW Scheduler provides functions that module PWM calls at begin and end of critical sections. Each PWM channel is linked to a hardware PWM which belongs to the microcontroller.
The PWM module generates pulses with variable pulse width and offers services to,
Start output of a PWM signal.
Stop output of a PWM signal.
Set parameters of a PWM channel’s waveform.
Set compare value for Events.
Enable/disable notifications.
Allows the selection of duty cycle and signal period time.
4.20.3.1. Initialization
The driver PWM is initialized by calling Pwm_Init() with a pointer to a configuration as parameter. To re-initialize call Pwm_DeInit() first and then Pwm_Init() with a different configuration.
The below table represents the PWM Channel state during the driver initialization
Point in time |
Module state |
|---|---|
Before Pwm_Init() |
PWM_STATUS_UNINIT |
After Pwm_Init() |
PWM_STATUS_INIT |
After Pwm_DeInit() |
PWM_STATUS_UNINIT |
4.20.3.2. Driver Architecture
The following figure shows where the PWM is located in the AUTOSAR architecture.
Fig. 4.86 PWM in AUTOSAR architecture
The AUTOSAR Architecture distinguishes on the highest abstraction level between three software layers Application, Runtime Environment and Basic Software which run on a Microcontroller.
PWM Driver: The Pwm driver is part of the microcontroller abstraction layer (MCAL). The driver provides functions for initialization and control of the microcontroller internal PWM stage (pulse width modulation).
Fig. 4.87 Interfaces to adjacent modules of the PWM
Refer Integration Details section for detail explanation on adjacent modules of the PWM.
4.20.3.3. Assumptions
None
4.20.3.4. Limitations
Depending on specific use case, either the CDD PWM or MCAL PWM module should be selected. Both should not be used together.
Same duty cycle will generate for both the channels EPWMxA and EPWMxB due to design constraint.
4.20.3.5. Design overview
Please refer SITARA MCU MCAL Architecture Document and AM26x MCAL: PWM Detailed Design Document provided as part of CSP.
4.20.4. Hardware Features
4.20.4.1. IP Supported Features
Dedicated 16-bit time-base counter with period and frequency control.
Up Down count mode.
The HRPWM works together with the ePWM registers to extend resolution.
Two PWM outputs (EPWMxA and EPWMxB) that can be used in the following configurations
Two independent PWM outputs with single edge operation.
Two independent PWM outputs with dual-edge symmetric operation.
The HRPWM is based on micro edge positioner(MEP) technology.
HRPWM feature should use the TI-supplied MEP scale factor optimizer (SFO) software function.The SFO function helps to dynamically determine the number of MEP steps per SYSCLKOUT period.
Same duty cycle will generate for both the channels EPWMxA and EPWMxB due to design constraint.
4.20.4.2. AUTOSAR Supported Features
Provide services to start and stop the output of pulse-width-modulated wave forms/signal.
Changing of frequency and duty cycle for a PWM channel at runtime besides the default configuration.
Enable/disable notifications. Allows the selection of duty cycle and signal period time.
There are a number of waveforms, which are supported by the PWM driver. The most widely used is standard PWM. Each period begins with an active state and changes to idle after the duty cycle has ended (see Figure below). Idle output is configurable allowing high or low for idle state according to requirement.
Fig. 4.88 Standard alignment left and right, expressed by high and low priority level
4.20.4.3. Not supported Features
APIs related to the power state. PwmgetOutputState API is not supported and it always returns LOW
Asynchronous override control of PWM signals through software.
Programmable phase-control support for lag or lead operation relative to other ePWM modules
Hardware-locked (synchronized) phase relationship on a cycle-by-cycle basis
Dead-band generation with independent rising and falling edge delay control.
Programmable trip zone allocation of both cycle-by-cycle trip and one-shot trip on fault conditions.
A trip condition can force either high,low,or high-impedance state logic levels at PWM outputs.
All events can trigger both CPU interrupts and ADC start of conversion (SOC).
Programmable event prescaling minimizes CPU overhead on interrupts.
PWM chopping by high-frequency carrier signal, useful for pulse transformer gate drives.
4.20.4.4. Non compliance
4.20.4.4.1. Deviations to requirements (Requirement Traceability)
4.20.4.4.1.1. Deviation of requirements against AUTOSAR specification requirements
Will be updated in next release
4.20.5. Source files
Static source C Files are defined below
📦AM263x
┣ 📂build
┣ 📂mcal
┃ ┣ 📂Pwm
┃ ┃ ┣ 📂include
┃ ┃ ┃ ┣ 📜Pwm.h : Contains the API’s of the PWM driver to be used by upper layers.
┃ ┃ ┣ 📂src
┃ ┃ ┃ ┣ 📜Pwm.c : Implementation of the API’s for PWM driver.
┃ ┃ ┣ 📂V0
┃ ┃ ┃ ┗ 📜Pwm_Irq.c : Contains ISR function definitions.
┃ ┃ ┃ ┣ 📜Pwm_Irq.h : Contains ISR function declaration.
┃ ┃ ┃ ┗ 📜Pwm_Priv.c : Contains Internal Functions Definitions.
┃ ┃ ┃ ┣ 📜Pwm_Priv.h : Contains data structures and Internal function declarations.
┃ ┃ ┃ ┗ 📜Pwm_Sfo.c : Contains the Macros and function definitions relate Scale factor optimizer for HRPWM.
┃ ┃ ┃ ┣ 📜Pwm_Sfo.h : Contains the Macros and function declaration.
┃ ┃ ┗ 📜Makefile
┃ 📂mcal_config
┃ 📂mcal_docs
┃ 📜README.txt
Plugin files are defined below in the table.
Plugin Files |
Description |
|---|---|
Pwm_Cfg.h |
Contains the base addresses, Precompile switches, Macros for channels, counters etc |
Pwm_PBcfg.c |
Contains all channels Post-Build Configuration parameters |
Pwm_Cfg.c |
Contains all channels Pre-Compile Configuration parameters |
The below diagram shows the files structure for the PWM driver.
Fig. 4.89 Header file structure of the PWM driver
4.20.6. Module requirements
Please refer Software Product Specification document provided as part of CSP.
4.20.6.1. Memory Mapping
The objects (e.g. variables, functions, constants) are declared by compiler independent definitions – the compiler abstraction definitions. Each compiler abstraction definition is assigned to a memory section. The following table contains the memory section names and the compiler abstraction definitions defined for the PWM and illustrate their assignment among each other.
Memory Mapping Sections |
PWM_CODE |
PWM_VAR_INIT |
PWM_VAR_NOINIT |
PWM_CONST |
PWM_CONFIG_DATA |
PWM_APPL_CODE |
|---|---|---|---|---|---|---|
PWM_START_SEC_VAR_INIT_UNSPECIFIED (.data) |
x |
|||||
PWM_STOP_SEC_VAR_INIT_UNSPECIFIED |
x |
|||||
PWM_START_SEC_CODE (.text) |
x |
|||||
PWM_STOP_SEC_CODE |
x |
|||||
PWM_START_SEC_VAR_NO_INIT_UNSPECIFIED (.bss) |
x |
|||||
PWM_STOP_SEC_VAR_NO_INIT_UNSPECIFIED |
x |
|||||
PWM_START_SEC_CONST_UNSPECIFIED (.rodata) |
x |
|||||
PWM_STOP_SEC_CONST_UNSPECIFIED |
x |
|||||
PWM_START_SEC_ISR_CODE (.text) |
x |
|||||
PWM_STOP_SEC_ISR_CODE |
x |
|||||
PWM_START_SEC_CONST_PTR (.rodata) |
x |
|||||
PWM_STOP_SEC_CONST_PTR |
x |
|||||
PWM_START_SEC_CONFIG_DATA (.data) |
x |
|||||
PWM_STOP_SEC_CONFIG_DATA |
x |
4.20.6.2. Scheduling
There are no scheduled functions within the PWM driver
4.20.6.3. Error handling
4.20.6.3.1. Development Error Reporting (DET)
By default, development errors are reported to the Development Error Tracer (DET) using the service Det_ReportError() if detection and reporting of development errors is enabled in the configuration tool. If another module is used for development error reporting, the function name for reporting the error can be configured by the integrator, but must have the same signature as the service Det_ReportError().
AUTOSAR requires that API functions shall check the validity of their respective parameters. The errors reported to DET are described in the following table
Type of Error |
Related Error code |
Value (Hex) |
|---|---|---|
Parameter ConfigPtr references NULL. |
PWM_E_PARAM_CONFIG |
0x10 |
API service used without module initialization of driver. |
PWM_E_UNINIT |
0x11 |
API parameter has invalid channel. |
PWM_E_PARAM_CHANNEL |
0x12 |
Usage of unauthorized PWM service on PWM channel configured a fixed period. |
PWM_E_PERIOD_UNCHANGEABLE |
0x13 |
API Pwm_Init service called while the module already initialized |
PWM_E_ALREADY_INITIALIZED |
0x14 |
API parameter passed with invalid pointer(NULL) |
PWM_E_PARAM_POINTER |
0x15 |
4.20.6.3.2. Runtime Errors
Type of Error |
Related Error code |
Value (Hex) |
|---|---|---|
API Pwm_SetPowerState is called while the PWM module is still in use(running). |
PWM_E_NOT_DISENGAGED |
0x16 |
4.20.7. Used resources
4.20.7.1. Interrupt Handling
For each of the configured hardware units, one interrupt service routine has to be mapped. The Integrator has to map the interrupt service routines to the interrupt sources of the respective PWM unit interrupt. The supported ISR’s are part of the Pwm_Irq.h file.
For interrupt notification, ISR’s are provided in PWM driver. There is one ISR for each PWM hardware unit. Depending on hardware unit configured, it will call group notify function. The interrupt service routines shall be mapped to the interrupt sources of the respective cross bar interrupt.
Hardware units |
ISR API Mapped |
|---|---|
0 |
Pwm_Ch0Isr( void ) |
1 |
Pwm_Ch1Isr( void ) |
2 |
Pwm_Ch2Isr( void ) |
3 |
Pwm_Ch3Isr( void ) |
4 |
Pwm_Ch4Isr( void ) |
5 |
Pwm_Ch5Isr( void ) |
6 |
Pwm_Ch6Isr( void ) |
7 |
Pwm_Ch7Isr( void ) |
8 |
Pwm_Ch8Isr( void ) |
9 |
Pwm_Ch9Isr( void ) |
10 |
Pwm_Ch10Isr( void ) |
… |
… |
126 |
Pwm_Ch126Isr( void ) |
127 |
Pwm_Ch127Isr( void ) |
4.20.8. Integration description
4.20.8.1. Dependent modules
4.20.8.1.1. OSEK / AUTOSAR OS (Optional)
An operating system can be used for task scheduling, interrupt handling, global suspend and restore of interrupts and creating of the Interrupt Vector Table. The PWM module may use OSEK/AUTOSAR OS to suspend and restore global interrupts.
4.20.8.1.2. MCU
The module MCU powers up the microcontroller’s peripherals at startup time and initializes the PLL(not directly) and the internal clock domains.
The PWM module depends on MCU module for enabling PWM clock for channel and crossbar interrupt mapping of PWM interrupts depending on the PWM channel configured.
Suppose the PWM channel 0 are configured for PWM module as shown in below figure:
Then, the MCU module container “McuPwmConfiguration” should be configured as shown in below figure:
Similarly, the crossbar interrupts also need to be mapped in MCU module according to PWM channel configured. The PWM interrupts needs to be mapped to the corresponding cross bar interrupt.
NOTE : McuPwmConfiguration and McuCddPwmConfiguration cannot be used together.
4.20.8.1.3. PORT
Module PORT configures the port pins that are used for output of PWM signal. For details see Technical Reference of Port.
4.20.8.1.4. DET
The module PWM depends on the DET (by default) in order to report development errors. Detection and reporting of development errors can be enabled or disabled by the switch.
“Enable Development Error Detection”.
The DET can be replaced optionally by an equivalent component which is responsible to recognize development errors, if no DET component is available.
4.20.8.1.5. Callback Notification
The Pwm driver provide configured notification call back for each interrupt occurred.
4.20.8.1.6. SchM (Optional)
If multiple AUTOSAR runnables have access to the same Data Store Memory block, the exported AUTOSAR specification enforces data consistency by using an AUTOSAR exclusive area. With this specification, the runnables have mutually exclusive access to the per-instance memory global data, which prevents data corruption. Beside the OS, the BSW Scheduler provides functions that PWM module calls at begin and end of critical sections. This implementation requires 1 level of exclusive access to guard critical sections.
The data consistency mechanism that has to be applied to an ExclusiveArea might be domain, ECU or even project specific. The decision which mechanism has to be applied by RTE / Basic Software Scheduler is taken during ECU integration by setting the Exclusive Area configuration parameter RteExclusiveAreaImplMechanism. This parameter is an input for RTE generator. For PWM Module, data consistency and exclusive access to critical sections are required for the following sections as shown in the table below:
Exclusive Area Functions used |
PWM Function calling Exclusive Area |
Need for Exclusive Area |
Recommended Exclusive Area Mapping |
|---|---|---|---|
PWM_EXCLUSIVE_AREA_0 |
Pwm_SetDutyCycle |
To protect against multiple access for shared resources |
ALL_INTERRUPT_BLOCKING : All interrupts should be blocked as this API’s can be called in the interrupts |
4.20.8.2. Multi-core support
Not supported
4.20.9. Configuration
4.20.9.1. PwmChannelConfigSet
This container contains the configuration parameters and sub containers of the AUTOSAR Pwm module.
4.20.9.1.1. PwmChannel
Configuration of an individual PWM channel.
4.20.9.1.1.1. PwmChannelClass
Item |
|
|---|---|
Name |
PwmChannelClass |
Description |
Class of PWM Channel. |
Multiplicity-Configuration-Class |
– |
Post-Build Time |
VARIANT-POST-BUILD |
Pre-Compile Time |
VARIANT-PRE-COMPILE |
Origin |
AUTOSAR_ECUC |
Post-build-variant-multiplicity |
true |
Post-Build-Variant-Value |
true |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
PWM_FIXED_PERIOD |
Range |
PWM_FIXED_PERIOD |
4.20.9.1.1.2. PwmChannelId
Item |
|
|---|---|
Name |
PwmChannelId |
Description |
Channel Id of the PWM channel. This value will be assigned to the symbolic name derived of the PwmChannel container short name. |
Origin |
AUTOSAR_ECUC |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Max-value |
255 |
Min-value |
0 |
4.20.9.1.1.3. PwmHWChannelId
Item |
|
|---|---|
Name |
PwmHWChannelId |
Description |
Channel Id of the PWM channel. This value will be assigned to the symbolic name derived of the PwmChannel container short name. |
Origin |
Texas Instruments |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
0 |
Max-value |
31 |
Min-value |
0 |
4.20.9.1.1.4. PwmHwUnit
Item |
|
|---|---|
Name |
PwmHwUnit |
Description |
The parameter PWM_IDLE_STATE represents the output state of the PWM after the signal is stopped (e.g. call of Pwm_SetOutputToIdle). |
Origin |
Texas Instruments |
Post-Build-Variant-Value |
true |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
PWM_CONTROLSS_G0 |
Range |
PWM_CONTROLSS_G0 |
4.20.9.1.1.5. PwmDutycycleDefault
Item |
|
|---|---|
Name |
PwmDutycycleDefault |
Description |
Value of duty cycle used for Initialization |
Origin |
AUTOSAR_ECUC |
Post-Build-Variant-Value |
true |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
16384 |
Max-value |
32768 |
Min-value |
0 |
4.20.9.1.1.6. PwmIdleState
Item |
|
|---|---|
Name |
PwmIdleState |
Description |
The parameter PWM_IDLE_STATE represents the output state of the PWM after the signal is stopped (e.g. call of Pwm_SetOutputToIdle). |
Origin |
AUTOSAR_ECUC |
Post-Build-Variant-Value |
true |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
PWM_HIGH |
Range |
PWM_HIGH |
4.20.9.1.1.7. PwmNotification
Item |
|
|---|---|
Name |
PwmNotification |
Description |
Definition of the Callback function. |
Multiplicity-Configuration-Class |
– |
Post-Build Time |
VARIANT-POST-BUILD |
Pre-Compile Time |
VARIANT-PRE-COMPILE |
Origin |
AUTOSAR_ECUC |
Post-build-variant-multiplicity |
true |
Post-Build-Variant-Value |
true |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
NULL_PTR |
4.20.9.1.1.8. PwmPeriodDefault
Item |
|
|---|---|
Name |
PwmPeriodDefault |
Description |
Value of period used for Initialization.(in seconds). |
Origin |
AUTOSAR_ECUC |
Post-Build-Variant-Value |
true |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
1.0 |
Max-value |
INF |
Min-value |
0.0 |
4.20.9.1.1.9. PwmOutputChSelect
Item |
|
|---|---|
Name |
PwmOutputChSelect |
Description |
PWM Output Channel select EPWMxA or EPWMxB or Both. Both Outputs available with same duty cycle, period and polarity. |
Origin |
Texas Instruments |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
PWM_OUTPUT_CH_A |
Range |
PWM_OUTPUT_CH_A |
4.20.9.1.1.10. PwmFunctionalClock
Item |
|
|---|---|
Name |
PwmFunctionalClock |
Description |
Value of the System clock frequency in Hz Default frequency is 125MHz for EPWM, and 25Mhz for GPT. |
Origin |
Texas Instruments |
Post-Build-Variant-Value |
true |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
19200000 |
4.20.9.1.1.11. PwmPolarity
Item |
|
|---|---|
Name |
PwmPolarity |
Description |
Defines the starting polarity of each PWM channel. |
Origin |
AUTOSAR_ECUC |
Post-Build-Variant-Value |
true |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
PWM_HIGH |
Range |
PWM_HIGH |
4.20.9.1.1.12. PwmClkPrescaler
Item |
|
|---|---|
Name |
PwmClkPrescaler |
Description |
The clock to Timer module is divided by the value specified here TBCLK = SYSCLKOUT / PwmClkPrescaler 0x0 = div by 1, 0x1 = div by 2, 0x2 = div by 4, 0x3 = div by 8, 0x4 = div by 16, 0x5 = div by 32 0x6 = div by 64, 0x7 = div by 128 |
Origin |
Texas Instruments |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
0 |
Max-value |
7 |
Min-value |
0 |
4.20.9.1.1.13. PwmHSClkPrescaler
Item |
|
|---|---|
Name |
PwmHSClkPrescaler |
Description |
High-Speed Time-base Clock Prescale Bits. These bits determine part of the time-base clock prescale value and acts as a clock divider for the time-base clock. TBCLK = SYSCLKOUT/(PwmHSClkPrescaler x PwmClkPrescaler) 0x0 = div by 1, 0x1 = div by 2, 0x2 = div by 4, 0x3 = div by 6, 0x4 = div by 8, 0x5 = div by 10 0x6 = div by 12, 0x7 = div by 14 |
Origin |
Texas Instruments |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
0 |
Max-value |
7 |
Min-value |
0 |
4.20.9.1.1.14. PwmEnableHighRes
Item |
|
|---|---|
Name |
PwmEnableHighRes |
Description |
This parameter will be a switch to enable or disable high resolution (HRPWM) capability of EPWM module. |
Origin |
Texas Instruments |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
false |
4.20.9.1.1.15. PwmMcuClockReferencePoint
Item |
|
|---|---|
Name |
PwmMcuClockReferencePoint |
Description |
This parameter contains reference to the McuClockReferencePoint |
Origin |
AUTOSAR_ECUC |
Post-Build-Variant-Value |
true |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
4.20.9.2. PwmConfigurationOfOptApiServices
4.20.9.2.1. PwmDeInitApi
Item |
|
|---|---|
Name |
PwmDeInitApi |
Description |
Adds / removes the service Pwm_DeInit() from the code. |
Origin |
AUTOSAR_ECUC |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
true |
4.20.9.2.2. PwmGetOutputState
Item |
|
|---|---|
Name |
PwmGetOutputState |
Origin |
AUTOSAR_ECUC |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
false |
4.20.9.2.3. PwmSetDutyCycle
Item |
|
|---|---|
Name |
PwmSetDutyCycle |
Origin |
AUTOSAR_ECUC |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
true |
4.20.9.2.4. PwmSetOutputToIdle
Item |
|
|---|---|
Name |
PwmSetOutputToIdle |
Origin |
AUTOSAR_ECUC |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
true |
4.20.9.2.5. PwmSetPeriodAndDuty
Item |
|
|---|---|
Name |
PwmSetPeriodAndDuty |
Origin |
AUTOSAR_ECUC |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
true |
4.20.9.2.6. PwmVersionInfoApi
Item |
|
|---|---|
Name |
PwmVersionInfoApi |
Description |
Switch to indicate that the Pwm_ GetVersionInfo is supported |
Origin |
AUTOSAR_ECUC |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
false |
4.20.9.2.7. PwmEnableRegisterReadbackApi
Item |
|
|---|---|
Name |
PwmEnableRegisterReadbackApi |
Description |
Switch to indicate that the Pwm_RegisterReadBack is supported |
Origin |
Texas Instruments |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
true |
4.20.9.3. PwmGeneral
4.20.9.3.1. PwmDevErrorDetect
Item |
|
|---|---|
Name |
PwmDevErrorDetect |
Description |
Switch for enabling the development error detection. |
Origin |
AUTOSAR_ECUC |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
true |
4.20.9.3.2. PwmSysClockFrequency
Item |
|
|---|---|
Name |
PwmSysClockFrequency |
Description |
Value of the System clock frequency in Hz Default frequency is 200MHz |
Origin |
Texas Instruments |
Post-Build-Variant-Value |
true |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Max-value |
200000000 |
Min-value |
1 |
4.20.9.3.3. PwmDutycycleUpdatedEndperiod
Item |
|
|---|---|
Name |
PwmDutycycleUpdatedEndperiod |
Description |
Switch for enabling the update of the duty cycle parameter at the end of the current period. |
Origin |
AUTOSAR_ECUC |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
true |
4.20.9.3.4. PwmSfoSupportEnable
Item |
|
|---|---|
Name |
PwmSfoSupportEnable |
Description |
Switch for enabling the SFO Inclusion for HRPWM ,If HRPWM is enabled. |
Origin |
Texas Instrument |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
false |
4.20.9.3.5. PwmDefaultOSCounterId
Item |
|
|---|---|
Name |
PwmDefaultOSCounterId |
Description |
Default Os Counter Id if node reference to OsCounter ref PwmOsCounterRef is not set |
Origin |
Texas Instruments |
Post-build-variant-multiplicity |
false |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
0 |
Max-value |
16 |
Min-value |
0 |
4.20.9.3.6. PwmMaxTimeoutDuration
Item |
|
|---|---|
Name |
PwmMaxTimeoutDuration |
Description |
Maximum time duration for PWM SFO status. Unit is in clock ticks. Configure the timeout according to r5f clock frequency(400MHz/200MHz) |
Origin |
Texas Instruments |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
10000 |
Max-value |
4294967295 |
Min-value |
1 |
4.20.9.3.7. PwmIndex
Item |
|
|---|---|
Name |
PwmIndex |
Description |
Specifies the InstanceId of this module instance. If only one instance is present it shall have the Id 0. |
Origin |
AUTOSAR_ECUC |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
1 |
Max-value |
1 |
Min-value |
0 |
4.20.9.3.8. PwmNotificationSupported
Item |
|
|---|---|
Name |
PwmNotificationSupported |
Description |
Switch to indicate that the notifications are supported |
Origin |
AUTOSAR_ECUC |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
true |
4.20.9.3.9. PwmPeriodUpdatedEndperiod
Item |
|
|---|---|
Name |
PwmPeriodUpdatedEndperiod |
Description |
Switch for enabling the update of the period parameter at the end of the current period. |
Origin |
AUTOSAR_ECUC |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
true |
4.20.9.3.10. PwmErrorHook
Item |
|
|---|---|
Name |
PwmErrorHook |
Description |
Used to report development errors. |
Origin |
Texas Instruments |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Post-Build-Time |
VARIANT-POST-BUILD |
Default-value |
Det_ReportError |
4.20.9.3.11. PwmDetIncludeFile
Item |
|
|---|---|
Name |
PwmDetIncludeFile |
Description |
Includes the header file where the Error hook function is defined. |
Origin |
Texas Instruments |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Post-Build-Time |
VARIANT-POST-BUILD |
Default-value |
Det.h |
4.20.9.3.12. PwmNotificationsIncludeFile
Item |
|
|---|---|
Name |
PwmNotificationsIncludeFile |
Description |
Includes the header file where the notification functions are defined. |
Origin |
Texas Instruments |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Post-Build-Time |
VARIANT-POST-BUILD |
Default-value |
None |
4.20.9.3.13. PwmCfgDebugReporting
Item |
|
|---|---|
Name |
PwmCfgDebugReporting |
Description |
Switch to Enable/disable debug support. |
Origin |
Texas Instruments |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
true |
4.20.9.3.14. PwmTypeofInterruptFunction
Item |
|
|---|---|
Name |
PwmTypeofInterruptFunction |
Description |
Type of ISR function |
Origin |
Texas Instruments |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
Default-value |
PWM_ISR_CAT1 |
Range |
PWM_ISR_VOID |
4.20.9.3.15. PwmOsCounterRef
Item |
|
|---|---|
Name |
PwmOsCounterRef |
Description |
This parameter contains a reference to the OsCounter, which is used by the PWM driver. |
Origin |
Texas Instruments |
Post-build-variant-multiplicity |
false |
Post-Build-Variant-Value |
false |
Value-Configuration-Class |
– |
Post-Build-Time |
VARIANT-POST-BUILD |
Pre-Compile-Time |
VARIANT-PRE-COMPILE |
4.20.9.3.16. PwmPowerStateConfig
Each instance of this parameter defines a power state and the callback to be called when this power state is reached.
Note: PwmMaxTimeoutDuration parameter Value should be passed as number of ticks according to clock frequency. The clock source have changed from RTI timers which used 200MHz clock frequency to R5f timers which uses 400MHz clock frequency, so the timeout values need to be configured accordingly.
4.20.9.4. Symbolic Names deviations
None
4.20.10. Examples
4.20.10.1. Overview
Initialize Timer and Interrupt using API PwmApp_Startup()
Initialize Clock (Mcu_Init), Port (Port_Init) and Uart using API Pwm_App_PlatformInit() in example application
Get PWM version info using Pwm_GetVersionInfo()
Call the function Pwm_App_FxnTbl() which in turn will call the API Pwm_App_MainTest()
Initialize the PWM configuration using Pwm_Init()
The PWM module is initialized with configured values : Dutycycle as 50% and Frequency as 1KHz
The PWM signal is changed to Dutycycle of 80 percent with Pwm_SetDutyCycle API
The PWM signal is changed to Dutycycle of 100 percent with Pwm_SetDutyCycle API
The PWM signal is made to output to Idle state with Pwm_SetOutputToIdle API
The PWM Frequency is changed to 10KHz and Dutycycle of 50 percent with Pwm_SetPeriodAndDuty API.
During every duty cycle change, probe the pin to see the output using Oscilloscope
4.20.10.2. Hardware Software Setup and Tools
None
4.20.10.3. Steps to build and run example
Pwm example application demonstrating the MCAL PWM driver features is in folder <MCAL_ROOT>/examples/Pwm.
This application can be built from the build folder by giving “gmake -s pwm_app PLATFORM= am263”.
Module is tested in AM263-CC board.
Oscilloscope is used to monitor PWM dutycycle and frequency Variation
The PWM module example is configured with channel id PWM_CHANNEL_PWM_CONTROLSS_G0_PWMCHANNEL9 , which is mapped to physical channel EPWM9
Connect EPWM output pin of 9th channel to Oscilloscope and check the output in CRO
Example code is tested for variation of Frequency and Duty cycle
4.20.10.4. Example Logs
PWM_APP: Sample Application - STARTS !!!
PWM_APP: PWM MCAL Version Info
---------------------
PWM_APP: Vendor ID : 44
PWM_APP: Module ID : 121
PWM_APP: SW Major Version : 9
PWM_APP: SW Minor Version : 1
PWM_APP: SW Patch Version : 0
PWM_APP: EPWM being used with Channel 0 !!!
PWM_APP: Variant - Post Build being used !!!
PWM_APP: Changing the Duty cycle from to 50 to 80 percent
PWM_APP: This example waits for 30 seconds Please probe
PWM_APP: Changing the Duty cycle to 100 Percent
PWM_APP: This example waits for 10 seconds Please probe
PWM_APP: Setting Output to Idle state
PWM_APP: This example waits for 10 seconds Please probe
PWM_APP: Changing Frequency from 1kHz to 10KHz and Duty Cycle to 50%
PWM_APP: period is set to 20000
PWM_APP: This app again waits for 30 seconds please probe
PWM_APP: Pwm Isr Count: 300000
PWM_APP: Disabling Notifications for PWM channel
PWM Test Completed !!!
PWM Stack Usage: 792 bytes
All tests have Passed !!!
PWM_APP: Sample Application - DONE !!!
4.20.10.5. File Structure
📦AM263x
┣ 📂build
┣ 📂mcal
┃ ┣ 📂examples
┃ ┃ ┣ 📂Pwm
┃ ┃ ┃ ┣ 📂soc
┃ ┃ ┃ ┣ 📜Makefile
┃ ┃ ┃ ┣ 📜PwmApp.c : Contains PWM test example.
┃ ┃ ┃ ┣ 📜PwmApp.h : Contains PWM test example header.
┃ ┣ 📂examples_config
┃ ┃ ┣ 📂Pwm_Demo_Cfg
┃ ┃ ┃ ┣ 📂soc
┃ ┃ ┃ ┃ ┣ 📂am263
┃ ┃ ┃ ┃ ┃ ┣ 📂r5f0_0
┃ ┃ ┃ ┃ ┃ ┃ ┣ 📂include
┃ ┃ ┃ ┃ ┃ ┃ ┃ ┣ 📜Pwm_Cfg.h : Contains the Precompile switches and macros.
┃ ┃ ┃ ┃ ┃ ┃ ┣ 📂src
┃ ┃ ┃ ┃ ┃ ┃ ┃ ┣ 📜Pwm_Cfg.c : Contains all Pre-Compile Configured parameters
┃ ┃ ┃ ┃ ┃ ┃ ┃ ┣ 📜Pwm_PBcfg.c : Contains all Post-Build Configured parameters
┃ 📂mcal_config
┃ 📂mcal_docs
┣ 📜README.txt
4.20.11. FAQ’s
Will be updated in next release