22 #define PULSES_PER_REVOLUTION 4
23 
24 int main(void) {
25 HAL_Init();
26 
27 Nucleo_BSP_Init();
28 MX_TIM1_Init();
29 MX_TIM3_Init();
30 
31 HAL_TIM_Encoder_Start(&htim3, TIM_CHANNEL_ALL);
32 HAL_TIM_OC_Start(&htim1, TIM_CHANNEL_1);
33 HAL_TIM_OC_Start(&htim1, TIM_CHANNEL_2);
34 
35 cnt1 = __HAL_TIM_GET_COUNTER(&htim3);
36 tick = HAL_GetTick();37 38 while (1) {
39 if (HAL_GetTick() - tick > 1000L) {
40 cnt2 = __HAL_TIM_GET_COUNTER(&htim3);
41 if (__HAL_TIM_IS_TIM_COUNTING_DOWN(&htim3)) {
42 if (cnt2  cnt1) /* Check for counter overflow */
48 diff = cnt2 - cnt1;
49 else
50 diff = (65535 - cnt1) + cnt2;
51 }
52 
53 sprintf(msg, "Difference: %d\r\n", diff);
54 HAL_UART_Transmit(&huart2, (uint8_t*) msg, strlen(msg), HAL_MAX_DELAY);
55 
56 speed = ((diff / PULSES_PER_REVOLUTION) / 60);
57 
58 /* If the first three bits of SMCR register are set to 0x3
59 * then the timer is set in X4 mode (TIM_ENCODERMODE_TI12)
60 * and we need to divide the pulses counter by two, because
61 * they include the pulses for both the channels */
62 if ((TIM3->SMCR & 0x3) == 0x3)
63 speed /= 2;
64 
65 sprintf(msg, "Speed: %d RPM\r\n", speed);
66 HAL_UART_Transmit(&huart2, (uint8_t*) msg, strlen(msg), HAL_MAX_DELAY);
67 
68 dir = __HAL_TIM_IS_TIM_COUNTING_DOWN(&htim3);
69 sprintf(msg, "Direction: %d\r\n", dir);
70 HAL_UART_Transmit(&huart2, (uint8_t*) msg, strlen(msg), HAL_MAX_DELAY);
71 
72 tick = HAL_GetTick();
73 cnt1 = __HAL_TIM_GET_COUNTER(&htim3);
74 }
75 
76 if (HAL_GPIO_ReadPin(GPIOC, GPIO_PIN_13) == GPIO_PIN_RESET) {
77 /* Invert rotation by swapping CH1 and CH2 CCR value */
78 tim1_ch1_pulse = __HAL_TIM_GET_COMPARE(&htim1, TIM_CHANNEL_1);
79 tim1_ch2_pulse = __HAL_TIM_GET_COMPARE(&htim1, TIM_CHANNEL_2);
80 
81 __HAL_TIM_SET_COMPARE(&htim1, TIM_CHANNEL_1, tim1_ch2_pulse);
82 __HAL_TIM_SET_COMPARE(&htim1, TIM_CHANNEL_2, tim1_ch1_pulse);
83 } 
84 }
85 }
86 
87 /* TIM1 init function */
88 void MX_TIM1_Init(void) {
89 TIM_OC_InitTypeDef sConfigOC;
90 
91 htim1.Instance = TIM1;
92 htim1.Init.Prescaler = 9;
93 htim1.Init.CounterMode = TIM_COUNTERMODE_UP;
94 htim1.Init.Period = 999;
95 HAL_TIM_Base_Init(&htim1);
96 
97 sConfigOC.OCMode = TIM_OCMODE_TOGGLE;
98 sConfigOC.Pulse = 499;
99 sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
100 sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
101 sConfigOC.OCIdleState = TIM_OCIDLESTATE_RESET;
102 sConfigOC.OCNPolarity = TIM_OCNPOLARITY_HIGH;
103 sConfigOC.OCNIdleState = TIM_OCNIDLESTATE_RESET;
104 HAL_TIM_OC_ConfigChannel(&htim1, &sConfigOC, TIM_CHANNEL_1);
105 
106 sConfigOC.Pulse = 999; /* Phase B is shifted by 90° */
107 HAL_TIM_OC_ConfigChannel(&htim1, &sConfigOC, TIM_CHANNEL_2);
108 }
109 
110 /* TIM3 init function */
111 void MX_TIM3_Init(void) {
112 TIM_Encoder_InitTypeDef sEncoderConfig;
113 
114 htim3.Instance = TIM3;
115 htim3.Init.Prescaler = 0;
116 htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
117 htim3.Init.Period = 65535;
118 
119 sEncoderConfig.EncoderMode = TIM_ENCODERMODE_TI12;
120 
121 sEncoderConfig.IC1Polarity = TIM_ICPOLARITY_RISING;
122 sEncoderConfig.IC1Selection = TIM_ICSELECTION_DIRECTTI;
123 sEncoderConfig.IC1Prescaler = TIM_ICPSC_DIV1;
124 sEncoderConfig.IC1Filter = 0;
125 
126 sEncoderConfig.IC2Polarity = TIM_ICPOLARITY_RISING;
127 sEncoderConfig.IC2Selection = TIM_ICSELECTION_DIRECTTI;
128 sEncoderConfig.IC2Prescaler = TIM_ICPSC_DIV1;
129 sEncoderConfig.IC2Filter = 0;
130 
131 HAL_TIM_Encoder_Init(&htim3, &sEncoderConfig);
132 }