EncoderCounter.cpp

00001 /*
00002  * EncoderCounter.cpp
00003  * Copyright (c) 2020, ZHAW
00004  * All rights reserved.
00005  */
00006 
00007 #include "EncoderCounter.h"
00008 
00009 using namespace std;
00010 
00011 /**
00012  * Creates and initialises the driver to read the quadrature
00013  * encoder counter of the STM32 microcontroller.
00014  * @param a the input pin for the channel A.
00015  * @param b the input pin for the channel B.
00016  */
00017 EncoderCounter::EncoderCounter(PinName a, PinName b) {
00018     
00019     // check pins
00020     
00021     if ((a == PA_15) && (b == PB_3)) {
00022         
00023         // pinmap OK for TIM2 CH1 and CH2
00024         
00025         TIM = TIM2;
00026         
00027         // configure reset and clock control registers
00028         
00029         RCC->AHB1ENR |= RCC_AHB1ENR_GPIOBEN;    // manually enable port B (port A enabled by mbed library)
00030         
00031         // configure general purpose I/O registers
00032         
00033         GPIOA->MODER &= ~GPIO_MODER_MODER15;    // reset port A15
00034         GPIOA->MODER |= GPIO_MODER_MODER15_1;   // set alternate mode of port A15
00035         GPIOA->PUPDR &= ~GPIO_PUPDR_PUPDR15;    // reset pull-up/pull-down on port A15
00036         GPIOA->PUPDR |= GPIO_PUPDR_PUPDR15_1;   // set input as pull-down
00037         GPIOA->AFR[1] &= ~0xF0000000;           // reset alternate function of port A15
00038         GPIOA->AFR[1] |= 1 << 4*7;              // set alternate funtion 1 of port A15
00039         
00040         GPIOB->MODER &= ~GPIO_MODER_MODER3;     // reset port B3
00041         GPIOB->MODER |= GPIO_MODER_MODER3_1;    // set alternate mode of port B3
00042         GPIOB->PUPDR &= ~GPIO_PUPDR_PUPDR3;     // reset pull-up/pull-down on port B3
00043         GPIOB->PUPDR |= GPIO_PUPDR_PUPDR3_1;    // set input as pull-down
00044         GPIOB->AFR[0] &= ~(0xF << 4*3);         // reset alternate function of port B3
00045         GPIOB->AFR[0] |= 1 << 4*3;              // set alternate funtion 1 of port B3
00046         
00047         // configure reset and clock control registers
00048         
00049         RCC->APB1RSTR |= RCC_APB1RSTR_TIM2RST;  //reset TIM2 controller
00050         RCC->APB1RSTR &= ~RCC_APB1RSTR_TIM2RST;
00051         
00052         RCC->APB1ENR |= RCC_APB1ENR_TIM2EN;     // TIM2 clock enable
00053         
00054     } else if ((a == PB_4) && (b == PC_7)) {
00055         
00056         // pinmap OK for TIM3 CH1 and CH2
00057         
00058         TIM = TIM3;
00059         
00060         // configure reset and clock control registers
00061         
00062         RCC->AHB1ENR |= RCC_AHB1ENR_GPIOBEN;    // manually enable port B
00063         RCC->AHB1ENR |= RCC_AHB1ENR_GPIOCEN;    // manually enable port C
00064         
00065         // configure general purpose I/O registers
00066         
00067         GPIOB->MODER &= ~GPIO_MODER_MODER4;     // reset port B4
00068         GPIOB->MODER |= GPIO_MODER_MODER4_1;    // set alternate mode of port B4
00069         GPIOB->PUPDR &= ~GPIO_PUPDR_PUPDR4;     // reset pull-up/pull-down on port B4
00070         GPIOB->PUPDR |= GPIO_PUPDR_PUPDR4_1;    // set input as pull-down
00071         GPIOB->AFR[0] &= ~(0xF << 4*4);         // reset alternate function of port B4
00072         GPIOB->AFR[0] |= 2 << 4*4;              // set alternate funtion 2 of port B4
00073         
00074         GPIOC->MODER &= ~GPIO_MODER_MODER7;     // reset port C7
00075         GPIOC->MODER |= GPIO_MODER_MODER7_1;    // set alternate mode of port C7
00076         GPIOC->PUPDR &= ~GPIO_PUPDR_PUPDR7;     // reset pull-up/pull-down on port C7
00077         GPIOC->PUPDR |= GPIO_PUPDR_PUPDR7_1;    // set input as pull-down
00078         GPIOC->AFR[0] &= ~0xF0000000;           // reset alternate function of port C7
00079         GPIOC->AFR[0] |= 2 << 4*7;              // set alternate funtion 2 of port C7
00080         
00081         // configure reset and clock control registers
00082         
00083         RCC->APB1RSTR |= RCC_APB1RSTR_TIM3RST;  //reset TIM3 controller
00084         RCC->APB1RSTR &= ~RCC_APB1RSTR_TIM3RST;
00085         
00086         RCC->APB1ENR |= RCC_APB1ENR_TIM3EN;     // TIM3 clock enable
00087         
00088     } else if ((a == PD_12) && (b == PD_13)) {
00089         
00090         // pinmap OK for TIM4 CH1 and CH2
00091         
00092         TIM = TIM4;
00093         
00094         // configure reset and clock control registers
00095         
00096         RCC->AHB1ENR |= RCC_AHB1ENR_GPIODEN;    // manually enable port D
00097         
00098         // configure general purpose I/O registers
00099         
00100         GPIOD->MODER &= ~GPIO_MODER_MODER12;    // reset port D12
00101         GPIOD->MODER |= GPIO_MODER_MODER12_1;   // set alternate mode of port D12
00102         GPIOD->PUPDR &= ~GPIO_PUPDR_PUPDR12;    // reset pull-up/pull-down on port D12
00103         GPIOD->PUPDR |= GPIO_PUPDR_PUPDR12_1;   // set input as pull-down
00104         GPIOD->AFR[1] &= ~(0xF << 4*4);         // reset alternate function of port D12
00105         GPIOD->AFR[1] |= 2 << 4*4;              // set alternate funtion 2 of port D12
00106         
00107         GPIOD->MODER &= ~GPIO_MODER_MODER13;    // reset port D13
00108         GPIOD->MODER |= GPIO_MODER_MODER13_1;   // set alternate mode of port D13
00109         GPIOD->PUPDR &= ~GPIO_PUPDR_PUPDR13;    // reset pull-up/pull-down on port D13
00110         GPIOD->PUPDR |= GPIO_PUPDR_PUPDR13_1;   // set input as pull-down
00111         GPIOD->AFR[1] &= ~(0xF << 4*5);         // reset alternate function of port D13
00112         GPIOD->AFR[1] |= 2 << 4*5;              // set alternate funtion 2 of port D13
00113         
00114         // configure reset and clock control registers
00115         
00116         RCC->APB1RSTR |= RCC_APB1RSTR_TIM4RST;  //reset TIM4 controller
00117         RCC->APB1RSTR &= ~RCC_APB1RSTR_TIM4RST;
00118         
00119         RCC->APB1ENR |= RCC_APB1ENR_TIM4EN;     // TIM4 clock enable
00120         
00121     } else {
00122         
00123         printf("pinmap not found for peripheral\n");
00124         
00125         TIM = NULL;
00126     }
00127     
00128     // configure general purpose timer 2, 3 or 4
00129     
00130     if (TIM != NULL) {
00131         
00132         TIM->CR1 = 0x0000;          // counter disable
00133         TIM->CR2 = 0x0000;          // reset master mode selection
00134         TIM->SMCR = TIM_SMCR_SMS_1 | TIM_SMCR_SMS_0; // counting on both TI1 & TI2 edges
00135         TIM->CCMR1 = TIM_CCMR1_CC2S_0 | TIM_CCMR1_CC1S_0;
00136         TIM->CCMR2 = 0x0000;        // reset capture mode register 2
00137         TIM->CCER = TIM_CCER_CC2E | TIM_CCER_CC1E;
00138         TIM->CNT = 0x0000;          // reset counter value
00139         TIM->ARR = 0xFFFF;          // auto reload register
00140         TIM->CR1 = TIM_CR1_CEN;     // counter enable
00141     }
00142 }
00143 
00144 /**
00145  * Deletes this EncoderCounter object.
00146  */
00147 EncoderCounter::~EncoderCounter() {}
00148 
00149 /**
00150  * Resets the counter value to zero.
00151  */
00152 void EncoderCounter::reset() {
00153     
00154     TIM->CNT = 0x0000;
00155 }
00156 
00157 /**
00158  * Resets the counter value to a given offset value.
00159  * @param offset the offset value to reset the counter to.
00160  */
00161 void EncoderCounter::reset(short offset) {
00162     
00163     TIM->CNT = -offset;
00164 }
00165 
00166 /**
00167  * Reads the quadrature encoder counter value.
00168  * @return the quadrature encoder counter as a signed 16-bit integer value.
00169  */
00170 short EncoderCounter::read() {
00171     
00172     return (short)(-TIM->CNT);
00173 }
00174 
00175 /**
00176  * The empty operator is a shorthand notation of the <code>read()</code> method.
00177  */
00178 EncoderCounter::operator short() {
00179     
00180     return read();
00181 }
00182