B-L072Z-LRWAN1 : PWM generation for LED dimming

Brain is for thinking!

• The board has MCU on it.
• MCU has timer peripherals.
• Timer peripherals can generate PWM on channel output.
• LED has to be connected to timer channel output.
• Board user manual has schematic where LED connections are shown.

AN4013 and AN4776 are good helpers for this task.

void pwm_setvalue(uint16_t value)
{
	TIM_OC_InitTypeDef sConfigOC;
	sConfigOC.OCMode = TIM_OCMODE_PWM2;
	sConfigOC.Pulse = value;
	sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
	sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
	HAL_TIM_PWM_ConfigChannel(&TimHandle, &sConfigOC, TIM_CHANNEL_1);
	HAL_TIM_PWM_Start(&TimHandle, TIM_CHANNEL_1);
}
 
void timer21_init(void)
{
 TimHandle.Instance = TIM21;
 TimHandle.Init.Prescaler = 0;
 TimHandle.Init.CounterMode = TIM_COUNTERMODE_UP;
 TimHandle.Init.Period = 3000;
 TimHandle.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
 HAL_TIM_PWM_Init(&TimHandle);
}
 
 
void gpio_tim_init(void)
{
	 /* Enable the GPIO_LED Clock */
	 __HAL_RCC_GPIOA_CLK_ENABLE();
 
	 /* Configure the GPIO_LED pin */
	 GPIO_InitStruct.Pin = GPIO_PIN_13;
	 GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
	 GPIO_InitStruct.Pull = GPIO_NOPULL;
	 GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
	 GPIO_InitStruct.Alternate = GPIO_AF6_TIM21;
 
	 //HAL_TIM_PWM_Start(&TimHandle, TIM_CHANNEL_1);
	 HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
 
}
 
 
int main( void )
{
 HAL_Init( );
 
 SystemClock_Config( );
 
 HW_Init( ); 
 
 gpio_tim_init();
 
 timer21_init();
 
 
 
 while(1)
 {
 		HAL_Delay(100);
 	 if(pwm_value == 0)
 		{
 			step = 100;
 		}
 
 
 	 if(pwm_value == 3000)
 		{
 			step = -100;
 		}
 
 	 pwm_value += step;
 	 pwm_setvalue(799);
 
}
 

Could u tell me what's wrong in this code because I am not getting PWM on pin PB13.