For those who use STM32 F10x as the MCU for Micromouse must remember all general purpose timers are 16bits that gave you 65535 max resolution. Since the mouse with fauhalber motor generate about 20000 encoder counts per cell distance traverse, we must keep track of the encoder counts to prevent overflow. Even though there were several methods to expand encoder resolution softwarely or hardwarely to 32bit, neither are preferred for this application.<\/p>\n
STM32F4 Series now have two 32bit general purpose timers: TIM2 and TIM5. Since the register capacity is now 32bit instead of 16bit for these 2 timers, the TIM2->CNT and TIM5->CNT registers can go beyond 65535(16bit) during in my test(obviously). If you decide to design a new mouse with stm32F4, having the 2 encoders connected to TIM2 and TIM5 will be a more no brainer choice to make your life my easier.<\/p>\n
The configuration code for encoder are very much likely same to STM32F10x, here is the code for setting TIM2 to quadrature encoder mode on STM32F4:<\/p>\n
void Encoder_Configration(void)<\/span><\/p>\n {<\/span><\/p>\n \u00a0\u00a0\u00a0 NVIC_InitTypeDef NVIC_InitStructure;<\/span><\/p>\n \u00a0 \u00a0 GPIO_InitTypeDef GPIO_InitStructure;<\/span><\/p>\n \u00a0\u00a0 TIM_TimeBaseInitTypeDef\u00a0 TIM_TimeBaseStructure; \u00a0\u00a0 TIM_ICInitTypeDef TIM_ICInitStructure;<\/span><\/p>\n \u00a0\u00a0 \/*TIM2 clock source enable *\/<\/span><\/p>\n \u00a0\u00a0 RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);<\/span><\/p>\n \u00a0\u00a0 \/* Enable GPIOA, clock *\/<\/span><\/p>\n \u00a0\u00a0 RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);\u00a0\u00a0\u00a0<\/span><\/p>\n \u00a0\u00a0 \/* Encoder unit connected to TIM2, quadrature mode *\/ \u00a0\u00a0<\/span><\/p>\n \u00a0 \/\/GPIOA Config\u00a0\u00a0<\/span><\/p>\n \u00a0\u00a0\u00a0 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;<\/span><\/p>\n \u00a0\u00a0\u00a0 GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;<\/span><\/p>\n \u00a0\u00a0\u00a0 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1;<\/span><\/p>\n \u00a0\u00a0\u00a0 GPIO_Init(GPIOA, &GPIO_InitStructure);<\/span><\/p>\n \u00a0<\/span><\/p>\n \u00a0\u00a0\u00a0 \/* Enable the TIM2 Update Interrupt for left encoder*\/\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/p>\n \u00a0\u00a0\u00a0 NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/p>\n \u00a0\u00a0\u00a0 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 6;<\/span><\/p>\n \u00a0\u00a0\u00a0 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;<\/span><\/p>\n \u00a0\u00a0\u00a0 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;<\/span><\/p>\n \u00a0\u00a0\u00a0 NVIC_Init(&NVIC_InitStructure);<\/span><\/p>\n \u00a0<\/span><\/p>\n \u00a0<\/span><\/p>\n \u00a0\u00a0\u00a0 \/* Timer configuration in Encoder mode for left encoder*\/<\/span><\/p>\n \u00a0\u00a0\u00a0 TIM_TimeBaseStructure.TIM_Prescaler = 0x00;\u00a0 \/\/ No prescaling<\/span><\/p>\n \u00a0\u00a0\u00a0 TIM_TimeBaseStructure.TIM_Period = 0xffffffff; \/\/max resolution<\/span><\/p>\n \u00a0\u00a0\u00a0 TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;\/\/devide by clock by one<\/span><\/p>\n \u00a0\u00a0\u00a0 TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;\/\/ count up\u00a0\u00a0<\/span><\/p>\n \u00a0\u00a0\u00a0 TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);<\/span><\/p>\n \u00a0<\/span><\/p>\n \u00a0\u00a0\u00a0 TIM_EncoderInterfaceConfig(TIM2, TIM_EncoderMode_TI12,\u00a0 TIM_ICPolarity_Falling, TIM_ICPolarity_Falling);<\/span><\/p>\n \u00a0\u00a0\u00a0 TIM_ICStructInit(&TIM_ICInitStructure);<\/span><\/p>\n \u00a0\u00a0\u00a0 TIM_ICInitStructure.TIM_ICFilter = 6;\/\/ICx_FILTER;<\/span><\/p>\n \u00a0\u00a0\u00a0 TIM_ICInit(TIM2, &TIM_ICInitStructure);<\/span><\/p>\n \u00a0\u00a0\u00a0 \/\/ Clear all pending interrupts<\/span><\/p>\n \u00a0\u00a0\u00a0 TIM_ClearFlag(TIM2, TIM_FLAG_Update);<\/span><\/p>\n \u00a0\u00a0\u00a0 TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);<\/span><\/p>\n \u00a0\u00a0\u00a0 \/\/Reset counter<\/span><\/p>\n \u00a0\u00a0\u00a0 TIM2->CNT = 10000;\/\/prevent exceeding 0 when turning wheel backwards<\/span><\/p>\n \u00a0\u00a0\u00a0 TIM_Cmd(TIM2, ENABLE);\/\/enable left encoder<\/span><\/p>\n }<\/span><\/p>\n Here are something even simpler:<\/p>\n void Encoder_Configration(void) GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; GPIO_PinAFConfig(GPIOA, GPIO_PinSource15, GPIO_AF_TIM2); TIM_SetAutoreload (TIM2, 0xffffffff); TIM_EncoderInterfaceConfig(TIM2, TIM_EncoderMode_TI12, TIM_ICPolarity_Rising, TIM_ICPolarity_Falling); For those who use STM32 F10x as the MCU for Micromouse must remember all general purpose timers are 16bits that gave you 65535 max resolution. Since the mouse with fauhalber motor generate about 20000 encoder counts per cell distance traverse, … Continue reading
\n<\/span><\/p>\n
\n{
\nGPIO_InitTypeDef GPIO_InitStructure;
\nRCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);<\/p>\n
\nGPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
\nGPIO_InitStructure.GPIO_Pin = GPIO_Pin_15;
\nGPIO_Init(GPIOA, &GPIO_InitStructure);
\nGPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;
\nGPIO_Init(GPIOB, &GPIO_InitStructure);<\/p>\n
\nGPIO_PinAFConfig(GPIOB, GPIO_PinSource3, GPIO_AF_TIM2);<\/p>\n
\n\/* Configure the timer *\/<\/p>\n
\n\/* TIM2 counter enable *\/
\nTIM_Cmd(TIM2, ENABLE);
\n}<\/p>\n","protected":false},"excerpt":{"rendered":"