[GD32E231 DIY Contest] 02. Why can’t the PWM duty cycle be changed in the external interrupt service function?

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[GD32E231 DIY Contest] 02. Why can’t the PWM duty cycle be changed in the external interrupt service function? [Copy link]

[GD32E231 DIY Contest] 02. Why can't the PWM duty cycle be changed in the external interrupt service function?

I tried to debug PWM this afternoon. Because I followed the routine, the whole process was relatively smooth, but something abnormal happened. When I tried to change the PWM duty cycle in the external interrupt function void EXTI4_15_IRQHandler(void), I found that it didn't work.

This problem has been solved: I misunderstood the routine and should have changed it in the EXT0_1 interrupt service function. . .

The specific situation is as follows:

First, in order to control the servo, I output a PWM wave with a duty cycle of 20ms and adjustable between 1ms and 2ms.

GPIO initialization:

1. void gpio_config(void) { rcu_periph_clock_enable(RCU_GPIOA); /* configure PA6(TIMER2 CH0) as alternate function */ gpio_mode_set(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO_PIN_6); gpio_output_options_set(GPIOA, GPIO _OTYPE_PP, GPIO_OSPEED_50MHZ,GPIO_PIN_6); gpio_af_set(GPIOA, GPIO_AF_1, GPIO_PIN_6); }

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External interrupt initialization:

1. void exti_config(void) { /* enable the clock */ rcu_periph_clock_enable(RCU_GPIOA); rcu_periph_clock_enable(RCU_CFGCMP) ; /* configure GPIO as input */ gpio_mode_set(GPIOA, GPIO_MODE_INPUT, GPIO_PUPD_PULLUP, GPIO_PIN_5); /* enable and set EXTI interrupt */ nvic_irq_enable(EXTI4_15_IRQn, 1U); /* connect EXTI line to GPIO pin */ syscfg_exti_line_config(EXTI_SOURCE_GPIOA, SOURCE_PIN5); /* configure EXTI line */ exti_init(EXTI_5, EXTI_INTERRUPT, EXTI_TRIG_FALLING); exti_interrupt_flag_clear(EXTI_5); }

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Timer initialization:

1. void timer_config(void) { /* ----------------------------------------------------------------------------- TIMER2CLK is TIME 100KHz R2 channel0 cycle = (25000/ 50000)* 100 = 50% ----------------------------------------------------------------------------- */ timer_oc_parameter_struct timer_ocintpara; timer_parameter_struct timer_initpara; rcu_periph_clock_enable(RCU_TIMER2); timer_deinit(TIMER2); /* TIMER configuration */ timer_initpara.prescaler = 719; duty _initpara.alignedmode = TIMER_COUNTER_EDGE; timer_initpara.counterdirection = TIMER_COUNTER_UP; //timer_initpara.period = 49999; timer_initpara.period = 1999; timer_initpara.clockdivision = TIMER_CKDIV_DIV1; timer_initpara.repetitioncounter = 0; timer_init(TIMER2,&timer_initpara); /* configure CH0 in PWM mode0 */ timer_ocintpara.ocpolarity = TIMER_OC_POLARITY_HIGH; timer_ocintpara.outputstate = TIMER_CCX_ENABLE; timer_channel_output_config(TIMER2,TIMER_CH_0,&timer_ocintpara); //timer_channel_output_pulse_value_config( TIMER2,TIMER_CH_0,24999); timer_channel_output_pulse_value_config(TIMER2,TIMER_CH_0,149); timer_channel_output_mode_config(TIMER2,TIMER_CH_0,TIMER_OC_MODE_PWM0); timer_channel_output_shadow_config(TIMER2,TIMER_CH_0,void EXTI4_15_IRQHandler(void) { if(RESET != exti_interrupt_flag_get(EXTI_5)){ gd_eval_led_toggle(LED1); timer_channel_output_pulse_value_config(TIMER2,TIMER_CH_0,199); } exti_interrupt_flag_clear(EXTI_5); } I don't know why it doesn't work here? I searched some posts about stm32 on the Internet, and it seems that this problem exists, but I didn't find any relevant explanation.... I tried to change the duty cycle in the SysTick interrupt service function: void SysTick_Handler(void) { delay_decrement(); timer_channel_output_pulse_value_config(TIMER2,TIMER_CH_0,199); } It can also be adjusted in the main function: while(1){ delay_1ms(5000); timer_channel_output_pulse_value_config(TIMER2,TIMER_CH_0,100); delay_1ms(5000); timer_channel_output_pulse_value_config(TIMER2,TIMER_CH_0,200); }

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This program is in the folder GD32E23x_Demo_Suites_V1.0.1\GD32E230C_START_Demo_Suites\Projects\04_TIMER_Key_EXTI. Please help me solve my problem. Thanks~ The attached picture is the PWM waveform I generated:

ddllxxrr

I think I need to reinitialize after the change, timer_init(TIMER2,&timer_initpara);

传媒学子

ddllxxrr posted on 2019-5-2 09:40 I think you have to reinitialize it after the change, timer_init(TIMER2,&timer_initpara);

However, there is no problem if you don't change it in the external interrupt.

ddllxxrr

Published by Media Student on 2019-5-3 17:35 However, if you don't modify it in the external interrupt, there will be no problem.

Maybe it's the privilege mechanism. When entering the interrupt, it becomes user mode and cannot be modified.

传媒学子

ddllxxrr posted on 2019-5-3 19:38 Maybe it's the privilege mechanism. When entering the interrupt, it becomes user mode and cannot be changed

I made a mistake. It can be changed in the interrupt. . .