The PWM wave is interrupted in mass production mode

[Wjian.1]

Hi:

Dear friends, there is a very strange problem here. I use timer 1(STM32MP157AAC) to output PWM wave. In engineering mode, the output of PWM wave is normal, but when it comes to mass production mode, the waveform is interrupted. Here are my configuration steps:

1)First of all, I configure the clock to be 209 MB, the frequency to be 800K, and the duty cycle to be 50%, as follows:

htim1.Instance = TIM1;
 htim1.Init.Prescaler = 0;
 htim1.Init.CounterMode = TIM_COUNTERMODE_UP;
 htim1.Init.Period = 250-1;
 htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
 htim1.Init.RepetitionCounter = 0;
 htim1.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_ENABLE;
 if (HAL_TIM_Base_Init(&htim1) != HAL_OK)
 {
 Error_Handler();
 }
 sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
 if (HAL_TIM_ConfigClockSource(&htim1, &sClockSourceConfig) != HAL_OK)
 {
 Error_Handler();
 }
 if (HAL_TIM_PWM_Init(&htim1) != HAL_OK)
 {
 Error_Handler();
 }
 sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
 sMasterConfig.MasterOutputTrigger2 = TIM_TRGO2_RESET;
 sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
 if (HAL_TIMEx_MasterConfigSynchronization(&htim1, &sMasterConfig) != HAL_OK)
 {
 Error_Handler();
 }
 sConfigOC.OCMode = TIM_OCMODE_PWM1;
 sConfigOC.Pulse = 125;
 sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
 sConfigOC.OCNPolarity = TIM_OCNPOLARITY_HIGH;
 sConfigOC.OCFastMode = TIM_OCFAST_ENABLE;
 sConfigOC.OCIdleState = TIM_OCIDLESTATE_RESET;
 sConfigOC.OCNIdleState = TIM_OCNIDLESTATE_RESET;
 if (HAL_TIM_PWM_ConfigChannel(&htim1, &sConfigOC, TIM_CHANNEL_3) != HAL_OK)
 {
 Error_Handler();
 }
 sBreakDeadTimeConfig.OffStateRunMode = TIM_OSSR_DISABLE;
 sBreakDeadTimeConfig.OffStateIDLEMode = TIM_OSSI_DISABLE;
 sBreakDeadTimeConfig.LockLevel = TIM_LOCKLEVEL_OFF;
 sBreakDeadTimeConfig.DeadTime = 0;
 sBreakDeadTimeConfig.BreakState = TIM_BREAK_DISABLE;
 sBreakDeadTimeConfig.BreakPolarity = TIM_BREAKPOLARITY_HIGH;
 sBreakDeadTimeConfig.BreakFilter = 0;
 sBreakDeadTimeConfig.BreakAFMode = TIM_BREAK_AFMODE_INPUT;
 sBreakDeadTimeConfig.Break2State = TIM_BREAK2_DISABLE;
 sBreakDeadTimeConfig.Break2Polarity = TIM_BREAK2POLARITY_HIGH;
 sBreakDeadTimeConfig.Break2Filter = 0;
 sBreakDeadTimeConfig.Break2AFMode = TIM_BREAK_AFMODE_INPUT;
 sBreakDeadTimeConfig.AutomaticOutput = TIM_AUTOMATICOUTPUT_DISABLE;
 if (HAL_TIMEx_ConfigBreakDeadTime(&htim1, &sBreakDeadTimeConfig) != HAL_OK)
 {
 Error_Handler();
 }

2)Configure the device tree as follows:

&pinctrl {
 u-boot,dm-pre-reloc;
 
 m4_tim1_pwm_pins_mx: m4_tim1_pwm_mx-0 {
 pins {
 pinmux = <STM32_PINMUX('E', 13, RSVD)>; /* TIM1_CH3 */
 };
 };
};
 
&m4_timers1{
 pinctrl-names = "default";
 pinctrl-0 = <&m4_tim1_pwm_pins_mx>;
 status = "okay";
 
 /* USER CODE BEGIN m4_timers1 */
 /* USER CODE END m4_timers1 */
};

3）TF-A is configured as follows:

DECPROT(STM32MP1_ETZPC_TIM1_ID, DECPROT_MCU_ISOLATION, DECPROT_UNLOCK)

4）Test waveform of mass production mode:

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​5）Could you tell me the solution?

[Wjian.1]

In addition, when you keep pressing the oscilloscope "SINGLE" button, the waveform interruption will be collected

[PatrickF]

Hi,

Did you have a fixed or a random recurrence of the 'missing PWM pulse' ?

Is the 'missing PWM pulse' always similar or have various location in the waveform ?

Could you zoom around the 'missing pulse' and check if the time between pulses is stretched (which might be linked to an unwanted short clock gating) or not (which might be linked to a timer signal output masked for a short period).

Regards.

[Wjian.1]

Hi:

Thank you for your reply. This "missing PWM pulse" in the mass production mode is not random. It is the "missing PWM pulse" every time you press the "single" button of the oscilloscope. This is not the case when debugging with IDE alone.The missing part only occurs in a single PWM cycle (1.25us)