107 lines
3.2 KiB
C
107 lines
3.2 KiB
C
#include <stdlib.h>
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#include <math.h>
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#include "IncrEncoder.h"
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#include "stm32f1xx_ll_gpio.h"
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#include "stm32f1xx_ll_bus.h"
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#include "stm32f1xx_ll_exti.h"
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#include "stm32f1xx_ll_tim.h"
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#define ZERO_POSITION 0
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#define TICKS_PER_REVOLUTION 360*4
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#define DEGREE_PER_TICKS 0.25
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int index_passed = 0;
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void INCR_ENCODER_Init(void){
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// GPIO initialization for channels a and b of the encoder
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LL_APB2_GRP1_EnableClock(LL_APB2_GRP1_PERIPH_GPIOA);
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LL_GPIO_InitTypeDef channel_a_pin_conf, channel_b_pin_conf;
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channel_a_pin_conf.Mode = LL_GPIO_MODE_FLOATING;
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channel_a_pin_conf.Pin = LL_GPIO_PIN_6;
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LL_GPIO_Init(GPIOA, &channel_a_pin_conf);
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channel_b_pin_conf.Mode = LL_GPIO_MODE_FLOATING;
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channel_b_pin_conf.Pin = LL_GPIO_PIN_7;
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LL_GPIO_Init(GPIOA, &channel_b_pin_conf);
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// timer init
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LL_APB1_GRP1_EnableClock(LL_APB1_GRP1_PERIPH_TIM3);
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LL_TIM_InitTypeDef tim3_init_struct;
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tim3_init_struct.Autoreload= TICKS_PER_REVOLUTION-1;
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tim3_init_struct.Prescaler=0;
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tim3_init_struct.ClockDivision=LL_TIM_CLOCKDIVISION_DIV1;
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tim3_init_struct.CounterMode=LL_TIM_COUNTERMODE_UP;
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tim3_init_struct.RepetitionCounter=0;
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LL_TIM_Init(TIM3, &tim3_init_struct);
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// timer as encoder init
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LL_TIM_ENCODER_InitTypeDef encoder_init_struct;
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encoder_init_struct.EncoderMode = LL_TIM_ENCODERMODE_X4_TI12;
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encoder_init_struct.IC1Polarity = LL_TIM_IC_POLARITY_RISING;
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encoder_init_struct.IC2Polarity = LL_TIM_IC_POLARITY_RISING;
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encoder_init_struct.IC1ActiveInput = LL_TIM_ACTIVEINPUT_DIRECTTI;
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encoder_init_struct.IC2ActiveInput = LL_TIM_ACTIVEINPUT_DIRECTTI;
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encoder_init_struct.IC1Prescaler = LL_TIM_ICPSC_DIV1;
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encoder_init_struct.IC2Prescaler= LL_TIM_ICPSC_DIV1;
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encoder_init_struct.IC1Filter = LL_TIM_IC_FILTER_FDIV1 ;
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encoder_init_struct.IC2Filter = LL_TIM_IC_FILTER_FDIV1 ;
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LL_TIM_ENCODER_Init(TIM3, &encoder_init_struct);
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LL_TIM_EnableCounter(TIM3);
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LL_APB2_GRP1_EnableClock(LL_APB2_GRP1_PERIPH_GPIOA);
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LL_APB2_GRP1_EnableClock(LL_APB2_GRP1_PERIPH_AFIO);
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// gpio init for index (interrup) pin
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LL_GPIO_InitTypeDef index_pin_conf;
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index_pin_conf.Pin = LL_GPIO_PIN_5;
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index_pin_conf.Mode = LL_GPIO_MODE_FLOATING;
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LL_GPIO_Init(GPIOC, &index_pin_conf);
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// exti init (interrupt)
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LL_EXTI_InitTypeDef exti;
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exti.Line_0_31 = LL_EXTI_LINE_5;
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exti.LineCommand = ENABLE;
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exti.Mode = LL_EXTI_MODE_IT;
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exti.Trigger = LL_EXTI_TRIGGER_RISING;
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LL_EXTI_Init(&exti);
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LL_GPIO_AF_SetEXTISource(LL_GPIO_AF_EXTI_PORTA, LL_GPIO_AF_EXTI_LINE5);
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// enable interrupt from exti in NVIC
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NVIC_SetPriority(EXTI9_5_IRQn, 12); // prio??
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NVIC_EnableIRQ(EXTI9_5_IRQn);
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}
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void EXTI9_5_IRQHandler(void){
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index_passed = 1;
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// reset counter = encoder position to 0 position
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LL_TIM_WriteReg(TIM3,CNT,0);
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// clear pending (EXTI necessary ?)
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LL_EXTI_ClearFlag_0_31(LL_EXTI_LINE_5);
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NVIC_ClearPendingIRQ(EXTI9_5_IRQn);
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}
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int INCR_ENCODER_IsAbsolute(void)
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{
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return index_passed;
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};
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float INCR_ENCODER_GetAngle(void)
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{
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int counter_value = LL_TIM_ReadReg(TIM3, CNT);
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// center
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int centered_counter_value = (counter_value - ZERO_POSITION) % TICKS_PER_REVOLUTION;
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// translate ticks to angle
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float angle = centered_counter_value * DEGREE_PER_TICKS;
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return angle;
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};
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