【简介】
S32K146 的PWM 可以通过FTM模块（FlexTimer Module）来输出，FTM 的每个channel 都可以配置为PWM 功能。PWM 按照模式可以分为Edge Aligned PWM 和 Center Aligned PWM 。
以下是Edge Aligned PWM 工作模式的时序
以下是Center Aligned PWM 工作模式的时序
【PWM引脚配置】
本地使用PTB5 作为PWM输出引脚，通过S32DS配置PTB5 pinmux 为ftm0 channel5.
【时钟配置】
FTM0 时钟配置为内部SIRC_DIV1为工作时钟
【PWM 参数配置】
PWM 通路参数配置
生成对应配置代码如下：
/***********************************************************************************************************************
* This file was generated by the S32 Configuration Tools. Any manual edits made to this file
* will be overwritten if the respective S32 Configuration Tools is used to update this file.
**********************************************************************************************************************/
/* clang-format off */
/* TEXT BELOW IS USED AS SETTING FOR TOOLS *************************************
!!GlobalInfo
product: Peripherals v14.0
processor: S32K146
package_id: S32K146_LQFP144
mcu_data: s32sdk_s32k1xx_rtm_401
processor_version: 0.0.0
functionalGroups:
- name: BOARD_InitPeripherals
UUID: 2d0c0af7-dbe7-4f00-821a-837510d6ab4e
called_from_default_init: true
selectedCore: core0
* BE CAREFUL MODIFYING THIS COMMENT - IT IS YAML SETTINGS FOR TOOLS **********/
/* clang-format on */
/*******************************************************************************
* Included files
******************************************************************************/
#include "peripherals_flexTimer_pwm_1.h"
/*******************************************************************************
* flexTimer_pwm_1 initialization code
******************************************************************************/
/* clang-format off */
/* TEXT BELOW IS USED AS SETTING FOR TOOLS *************************************
instance:
- name: 'flexTimer_pwm_1'
- type: 'flexTimer_pwm'
- mode: 'general'
- custom_name_enabled: 'false'
- type_id: 'ftm_pwm'
- functional_group: 'BOARD_InitPeripherals'
- peripheral: 'FTM_0'
- config_sets:
- ftm_pwm:
- ftmPwmUserConfig:
- ftmPwmInitConfig:
- ftmPwmClkCfg:
- ClockSource: 'FTM_CLOCK_SOURCE_SYSTEMCLK'
- ftmprescaler: '4'
- ftmPwmGlobalCfg:
- ftmMode: 'FTM_MODE_EDGE_ALIGNED_PWM'
- debugMode: 'FTM_BDM_MODE_00'
- timerOverInter: 'false'
- initTrigger: 'false'
- ftmPwmRegSyncCfg:
- softTrigger: 'true'
- hardwareTrigger1: 'false'
- hardwareTrigger2: 'false'
- hardwareTrigger3: 'false'
- ftmSyncPoint: 'FTM_UPDATE_NOW'
- maxload: 'false'
- minload: 'false'
- AutoTrigClear: 'false'
- ftmRegisterUpdate: 'FTM_PWM_SYNC'
- ftmSoftwareOutControl: 'FTM_PWM_SYNC'
- ftmOutMaskSync: 'FTM_PWM_SYNC'
- ftmCounterInitSync: 'FTM_PWM_SYNC'
- ftmPwmConfiguration:
- ftmPwmGeneralCfg:
- periodInFreq: '1000000'
- deadTimeValue: '0'
- deadTimePrescaler: 'FTM_DEADTIME_DIVID_BY_1'
- FtmPwmConfigArr:
- faultConfig:
- faultMode: 'FTM_FAULT_CONTROL_DISABLED'
- pwmFaultInterrupt: 'false'
- faultFilterValue: '0'
- pwmOutputStateOnFault: 'false'
- ftmFaultChannelParam:
- 0:
- faultChannelEnabled: 'false'
- faultFilterEnabled: 'false'
- ftmFaultPinPolarity: 'FTM_POLARITY_LOW'
- 1:
- faultChannelEnabled: 'false'
- faultFilterEnabled: 'false'
- ftmFaultPinPolarity: 'FTM_POLARITY_LOW'
- 2:
- faultChannelEnabled: 'false'
- faultFilterEnabled: 'false'
- ftmFaultPinPolarity: 'FTM_POLARITY_LOW'
- 3:
- faultChannelEnabled: 'false'
- faultFilterEnabled: 'false'
- ftmFaultPinPolarity: 'FTM_POLARITY_LOW'
- ftmPwmIndptChnCfg:
- pwmIndependentChannelConfig:
- 0:
- ftmpwmIndptName: 'flexTimer_pwm_1_IndependentChannelConfig0'
- ftmPwmIndptHwChnId: '5'
- polarity: 'FTM_POLARITY_LOW'
- uDutyCyclePercent: '0x4000'
- enableExternalTrigger: 'false'
- safeState: 'FTM_LOW_STATE'
- enableSecondChannelOutput: 'false'
- secondChannelPolarity: 'FTM_MAIN_INVERTED'
- IndptdeadTimeEn: 'false'
- ftmPwmCombChnCfg:
- pwmCombinedChannelConfig: []
* BE CAREFUL MODIFYING THIS COMMENT - IT IS YAML SETTINGS FOR TOOLS **********/
/* clang-format on */
/**
* @page misra_violations MISRA-C:2012 violations
*
* @section [global]
* Violates MISRA 2012 Advisory Rule 8.7, External variable could be made static.
* The external variables will be used in other source files in application code.
*
*/
/* Global configuration of flexTimer_pwm_1 InitConfig */
ftm_user_config_t flexTimer_pwm_1_InitConfig =
{
{
true, /* Software trigger state */
false, /* Hardware trigger 1 state */
false, /* Hardware trigger 2 state */
false, /* Hardware trigger 3 state */
false, /* Max loading point state */
false, /* Min loading point state */
FTM_PWM_SYNC, /* Update mode for INVCTRL register */
FTM_PWM_SYNC, /* Update mode for SWOCTRL register */
FTM_PWM_SYNC, /* Update mode for OUTMASK register */
FTM_PWM_SYNC, /* Update mode for CNTIN register */
true, /* Automatic clear of the trigger*/
FTM_UPDATE_NOW, /* Synchronization point */
},
FTM_MODE_EDGE_ALIGNED_PWM, /* Mode of operation for FTM */
FTM_CLOCK_DIVID_BY_4, /* FTM clock prescaler */
FTM_CLOCK_SOURCE_SYSTEMCLK, /* FTM clock source */
FTM_BDM_MODE_00, /* FTM debug mode */
false, /* Interrupt state */
false /* Initialization trigger */
};
/* Fault configuration structure for flexTimer_pwm_1*/
ftm_pwm_fault_param_t flexTimer_pwm_1_FaultConfig =
{
false, /* Output pin state on fault */
false, /* PWM fault interrupt state */
0U, /* Fault filter value */
FTM_FAULT_CONTROL_DISABLED, /* Fault mode */
{
{
false, /* Fault channel state (Enabled/Disabled) */
false, /* Fault channel filter state (Enabled/Disabled) */
FTM_POLARITY_LOW, /* Fault channel state (Enabled/Disabled) */
},
{
false, /* Fault channel state (Enabled/Disabled) */
false, /* Fault channel filter state (Enabled/Disabled) */
FTM_POLARITY_LOW, /* Fault channel state (Enabled/Disabled) */
},
{
false, /* Fault channel state (Enabled/Disabled) */
false, /* Fault channel filter state (Enabled/Disabled) */
FTM_POLARITY_LOW, /* Fault channel state (Enabled/Disabled) */
},
{
false, /* Fault channel state (Enabled/Disabled) */
false, /* Fault channel filter state (Enabled/Disabled) */
FTM_POLARITY_LOW, /* Fault channel state (Enabled/Disabled) */
},
}
};
/* The independent channels configuration structure for flexTimer_pwm_1_IndependentChannelsConfig */
ftm_independent_ch_param_t flexTimer_pwm_1_IndependentChannelsConfig[1] =
{
{
5, /* Hardware channel Id */
FTM_POLARITY_LOW, /* Polarity of the PWM signal */
16384U, /* Duty cycle percent 0-0x8000 */
false, /* External Trigger */
FTM_LOW_STATE, /* Safe state of the PWM channel when faults are detected */
false, /* Enabled/disabled the channel (n+1) output */
FTM_MAIN_INVERTED, /* Select channel (n+1) output relative to channel (n) */
false, /* Dead time enabled/disabled */
}
};
/* PWM configuration for flexTimer_pwm_1 */
ftm_pwm_param_t flexTimer_pwm_1_PwmConfig =
{
1U, /* Number of independent PWM channels */
0U, /* Number of combined PWM channels */
FTM_MODE_EDGE_ALIGNED_PWM, /* PWM mode */
0U, /* Dead time value */
FTM_DEADTIME_DIVID_BY_1, /* Dead time prescale */
1000000U, /* PWM frequency */
flexTimer_pwm_1_IndependentChannelsConfig, /* The independent PWM channels configuration structure */
NULL, /* Combined PWM channels configuration structure */
&flexTimer_pwm_1_FaultConfig /* PWM fault configuration structure */
};【代码验证】
添加以下代码初始化pwm 输出1Mhz 50%的占空比配置
static int pwm_init(void)
{
status_t ret;
/* config pwm timer */
ret = FTM_DRV_Init(INST_FLEXTIMER_PWM_1, &flexTimer_pwm_1_InitConfig, &ftm0_pwm_state);
if(ret != STATUS_SUCCESS)
{
LOG_E("Ftm0 init failed %x.",ret);
}
else
{
LOG_I("Ftm0 init OK.");
}
ret = FTM_DRV_InitPwm(INST_FLEXTIMER_PWM_1, &flexTimer_pwm_1_PwmConfig);
if(ret != STATUS_SUCCESS)
{
LOG_E("Ftm0 pwm init failed %x.",ret);
}
else
{
LOG_I("Ftm0 pwm init OK.");
}
return 1;
}
INIT_BOARD_EXPORT_LEVEL1(pwm_init);运行后PTB5 引脚按照预期的输出PWM 1MHZ 50% 占空比的信号
添加如下代码更新占空比配置
/********************************************************************************************************
* Private Function Declarations *
*******************************************************************************************************/
unsigned int pwm(char argc,char *argv[])
{
uint16_t duty;
uint16_t firstEdge;
status_t ret;
if(argc == 2)
{
duty = atoi(argv[1]);
firstEdge = FTM_MAX_DUTY_CYCLE*duty*100/10000;
ret = FTM_DRV_UpdatePwmChannel(INST_FLEXTIMER_PWM_1,5U,FTM_PWM_UPDATE_IN_DUTY_CYCLE,firstEdge,0U,true);
if(ret != STATUS_SUCCESS)
{
LOG_E("Ftm0 pwm update failed %x.",ret);
}
else
{
LOG_I("Ftm0 pwm update OK.");
}
}
return 0;
}pwm 配置为25% 后查看PWM 波形已经按照预期的配置为25%
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