EncoderCounter.cpp

00001 /*
00002  * EncoderCounter.cpp
00003  * Copyright (c) 2018, ZHAW
00004  * All rights reserved.
00005  */
00006 
00007 #include "EncoderCounter.h"
00008 
00009 using namespace std;
00010 
00011 /**
00012  * Creates and initializes 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_0) && (b == PA_1)) {
00022         
00023         // pinmap OK for TIM2 CH1 and CH2
00024         
00025         TIM = TIM2;
00026         
00027         // configure general purpose I/O registers
00028         
00029         GPIOA->MODER &= ~GPIO_MODER_MODER0;     // reset port A0
00030         GPIOA->MODER |= GPIO_MODER_MODER0_1;    // set alternate mode of port A0
00031         GPIOA->PUPDR &= ~GPIO_PUPDR_PUPDR0;     // reset pull-up/pull-down on port A0
00032         GPIOA->PUPDR |= GPIO_PUPDR_PUPDR0_1;    // set input as pull-down
00033         GPIOA->AFR[0] &= ~(0xF << 4*0);         // reset alternate function of port A0
00034         GPIOA->AFR[0] |= 1 << 4*0;              // set alternate funtion 1 of port A0
00035         
00036         GPIOA->MODER &= ~GPIO_MODER_MODER1;     // reset port A1
00037         GPIOA->MODER |= GPIO_MODER_MODER1_1;    // set alternate mode of port A1
00038         GPIOA->PUPDR &= ~GPIO_PUPDR_PUPDR1;     // reset pull-up/pull-down on port A1
00039         GPIOA->PUPDR |= GPIO_PUPDR_PUPDR1_1;    // set input as pull-down
00040         GPIOA->AFR[0] &= ~(0xF << 4*1);         // reset alternate function of port A1
00041         GPIOA->AFR[0] |= 1 << 4*1;              // set alternate funtion 1 of port A1
00042         
00043         // configure reset and clock control registers
00044         
00045         RCC->APB1RSTR |= RCC_APB1RSTR_TIM2RST;  //reset TIM2 controller
00046         RCC->APB1RSTR &= ~RCC_APB1RSTR_TIM2RST;
00047         
00048         RCC->APB1ENR |= RCC_APB1ENR_TIM2EN;     // TIM2 clock enable
00049         
00050     } else if ((a == PA_6) && (b == PC_7)) {
00051         
00052         // pinmap OK for TIM3 CH1 and CH2
00053         
00054         TIM = TIM3;
00055         
00056         // configure reset and clock control registers
00057         
00058         RCC->AHB1ENR |= RCC_AHB1ENR_GPIOCEN;    // manually enable port C (port A enabled by mbed library)
00059         
00060         // configure general purpose I/O registers
00061         
00062         GPIOA->MODER &= ~GPIO_MODER_MODER6;     // reset port A6
00063         GPIOA->MODER |= GPIO_MODER_MODER6_1;    // set alternate mode of port A6
00064         GPIOA->PUPDR &= ~GPIO_PUPDR_PUPDR6;     // reset pull-up/pull-down on port A6
00065         GPIOA->PUPDR |= GPIO_PUPDR_PUPDR6_1;    // set input as pull-down
00066         GPIOA->AFR[0] &= ~(0xF << 4*6);         // reset alternate function of port A6
00067         GPIOA->AFR[0] |= 2 << 4*6;              // set alternate funtion 2 of port A6
00068         
00069         GPIOC->MODER &= ~GPIO_MODER_MODER7;     // reset port C7
00070         GPIOC->MODER |= GPIO_MODER_MODER7_1;    // set alternate mode of port C7
00071         GPIOC->PUPDR &= ~GPIO_PUPDR_PUPDR7;     // reset pull-up/pull-down on port C7
00072         GPIOC->PUPDR |= GPIO_PUPDR_PUPDR7_1;    // set input as pull-down
00073         GPIOC->AFR[0] &= ~0xF0000000;           // reset alternate function of port C7
00074         GPIOC->AFR[0] |= 2 << 4*7;              // set alternate funtion 2 of port C7
00075         
00076         // configure reset and clock control registers
00077         
00078         RCC->APB1RSTR |= RCC_APB1RSTR_TIM3RST;  //reset TIM3 controller
00079         RCC->APB1RSTR &= ~RCC_APB1RSTR_TIM3RST;
00080         
00081         RCC->APB1ENR |= RCC_APB1ENR_TIM3EN;     // TIM3 clock enable
00082         
00083     } else if ((a == PB_6) && (b == PB_7)) {
00084         
00085         // pinmap OK for TIM4 CH1 and CH2
00086         
00087         TIM = TIM4;
00088         
00089         // configure reset and clock control registers
00090         
00091         RCC->AHB1ENR |= RCC_AHB1ENR_GPIOBEN;    // manually enable port B (port A enabled by mbed library)
00092         
00093         // configure general purpose I/O registers
00094         
00095         GPIOB->MODER &= ~GPIO_MODER_MODER6;     // reset port B6
00096         GPIOB->MODER |= GPIO_MODER_MODER6_1;    // set alternate mode of port B6
00097         GPIOB->PUPDR &= ~GPIO_PUPDR_PUPDR6;     // reset pull-up/pull-down on port B6
00098         GPIOB->PUPDR |= GPIO_PUPDR_PUPDR6_1;    // set input as pull-down
00099         GPIOB->AFR[0] &= ~(0xF << 4*6);         // reset alternate function of port B6
00100         GPIOB->AFR[0] |= 2 << 4*6;              // set alternate funtion 2 of port B6
00101         
00102         GPIOB->MODER &= ~GPIO_MODER_MODER7;     // reset port B7
00103         GPIOB->MODER |= GPIO_MODER_MODER7_1;    // set alternate mode of port B7
00104         GPIOB->PUPDR &= ~GPIO_PUPDR_PUPDR7;     // reset pull-up/pull-down on port B7
00105         GPIOB->PUPDR |= GPIO_PUPDR_PUPDR7_1;    // set input as pull-down
00106         GPIOB->AFR[0] &= ~0xF0000000;           // reset alternate function of port B7
00107         GPIOB->AFR[0] |= 2 << 4*7;              // set alternate funtion 2 of port B7
00108         
00109         // configure reset and clock control registers
00110         
00111         RCC->APB1RSTR |= RCC_APB1RSTR_TIM4RST;  //reset TIM4 controller
00112         RCC->APB1RSTR &= ~RCC_APB1RSTR_TIM4RST;
00113         
00114         RCC->APB1ENR |= RCC_APB1ENR_TIM4EN;     // TIM4 clock enable
00115         
00116     } else {
00117         
00118         printf("pinmap not found for peripheral\n");
00119     }
00120     
00121     // configure general purpose timer 3 or 4
00122     
00123     TIM->CR1 = 0x0000;          // counter disable
00124     TIM->CR2 = 0x0000;          // reset master mode selection
00125     TIM->SMCR = TIM_SMCR_SMS_1 | TIM_SMCR_SMS_0; // counting on both TI1 & TI2 edges
00126     TIM->CCMR1 = TIM_CCMR1_CC2S_0 | TIM_CCMR1_CC1S_0;
00127     TIM->CCMR2 = 0x0000;        // reset capture mode register 2
00128     TIM->CCER = TIM_CCER_CC2E | TIM_CCER_CC1E;
00129     TIM->CNT = 0x0000;          // reset counter value
00130     TIM->ARR = 0xFFFF;          // auto reload register
00131     TIM->CR1 = TIM_CR1_CEN;     // counter enable
00132 }
00133 
00134 EncoderCounter::~EncoderCounter() {}
00135 
00136 /**
00137  * Resets the counter value to zero.
00138  */
00139 void EncoderCounter::reset() {
00140     
00141     TIM->CNT = 0x0000; 
00142 }
00143 
00144 /**
00145  * Resets the counter value to a given offset value.
00146  * @param offset the offset value to reset the counter to.
00147  */
00148 void EncoderCounter::reset(short offset) {
00149     
00150     TIM->CNT = -offset;
00151 }
00152 
00153 /**
00154  * Reads the quadrature encoder counter value.
00155  * @return the quadrature encoder counter as a signed 16-bit integer value.
00156  */
00157 short EncoderCounter::read() {
00158     
00159     return (short)(-TIM->CNT);
00160 }
00161 
00162 /**
00163  * The empty operator is a shorthand notation of the <code>read()</code> method.
00164  */
00165 EncoderCounter::operator short() {
00166     
00167     return read();
00168 }