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 
00020     // check pins
00021 
00022     if ((a == PA_0) && (b == PA_1)) {
00023 
00024         // pinmap OK for TIM2 CH1 and CH2
00025 
00026         TIM = TIM2;
00027 
00028         // configure general purpose I/O registers
00029 
00030         GPIOA->MODER &= ~GPIO_MODER_MODER0;     // reset port A0
00031         GPIOA->MODER |= GPIO_MODER_MODER0_1;    // set alternate mode of port A0
00032         GPIOA->PUPDR &= ~GPIO_PUPDR_PUPDR0;     // reset pull-up/pull-down on port A0
00033         GPIOA->PUPDR |= GPIO_PUPDR_PUPDR0_1;    // set input as pull-down
00034         GPIOA->AFR[0] &= ~(0xF << 4*0);         // reset alternate function of port A0
00035         GPIOA->AFR[0] |= 1 << 4*0;              // set alternate funtion 1 of port A0
00036 
00037         GPIOA->MODER &= ~GPIO_MODER_MODER1;     // reset port A1
00038         GPIOA->MODER |= GPIO_MODER_MODER1_1;    // set alternate mode of port A1
00039         GPIOA->PUPDR &= ~GPIO_PUPDR_PUPDR1;     // reset pull-up/pull-down on port A1
00040         GPIOA->PUPDR |= GPIO_PUPDR_PUPDR1_1;    // set input as pull-down
00041         GPIOA->AFR[0] &= ~(0xF << 4*1);         // reset alternate function of port A1
00042         GPIOA->AFR[0] |= 1 << 4*1;              // set alternate funtion 1 of port A1
00043 
00044         // configure reset and clock control registers
00045 
00046         RCC->APB1RSTR |= RCC_APB1RSTR_TIM2RST;  //reset TIM2 controller
00047         RCC->APB1RSTR &= ~RCC_APB1RSTR_TIM2RST;
00048 
00049         RCC->APB1ENR |= RCC_APB1ENR_TIM2EN;     // TIM2 clock enable
00050 
00051     } else if ((a == PA_6) && (b == PC_7)) {
00052 
00053         // pinmap OK for TIM3 CH1 and CH2
00054 
00055         TIM = TIM3;
00056 
00057         // configure reset and clock control registers
00058 
00059         RCC->AHB1ENR |= RCC_AHB1ENR_GPIOCEN;    // manually enable port C (port A enabled by mbed library)
00060 
00061         // configure general purpose I/O registers
00062 
00063         GPIOA->MODER &= ~GPIO_MODER_MODER6;     // reset port A6
00064         GPIOA->MODER |= GPIO_MODER_MODER6_1;    // set alternate mode of port A6
00065         GPIOA->PUPDR &= ~GPIO_PUPDR_PUPDR6;     // reset pull-up/pull-down on port A6
00066         GPIOA->PUPDR |= GPIO_PUPDR_PUPDR6_1;    // set input as pull-down
00067         GPIOA->AFR[0] &= ~(0xF << 4*6);         // reset alternate function of port A6
00068         GPIOA->AFR[0] |= 2 << 4*6;              // set alternate funtion 2 of port A6
00069 
00070         GPIOC->MODER &= ~GPIO_MODER_MODER7;     // reset port C7
00071         GPIOC->MODER |= GPIO_MODER_MODER7_1;    // set alternate mode of port C7
00072         GPIOC->PUPDR &= ~GPIO_PUPDR_PUPDR7;     // reset pull-up/pull-down on port C7
00073         GPIOC->PUPDR |= GPIO_PUPDR_PUPDR7_1;    // set input as pull-down
00074         GPIOC->AFR[0] &= ~0xF0000000;           // reset alternate function of port C7
00075         GPIOC->AFR[0] |= 2 << 4*7;              // set alternate funtion 2 of port C7
00076 
00077         // configure reset and clock control registers
00078 
00079         RCC->APB1RSTR |= RCC_APB1RSTR_TIM3RST;  //reset TIM3 controller
00080         RCC->APB1RSTR &= ~RCC_APB1RSTR_TIM3RST;
00081 
00082         RCC->APB1ENR |= RCC_APB1ENR_TIM3EN;     // TIM3 clock enable
00083 
00084     } else if ((a == PB_6) && (b == PB_7)) {
00085 
00086         // pinmap OK for TIM4 CH1 and CH2
00087 
00088         TIM = TIM4;
00089 
00090         // configure reset and clock control registers
00091 
00092         RCC->AHB1ENR |= RCC_AHB1ENR_GPIOBEN;    // manually enable port B (port A enabled by mbed library)
00093 
00094         // configure general purpose I/O registers
00095 
00096         GPIOB->MODER &= ~GPIO_MODER_MODER6;     // reset port B6
00097         GPIOB->MODER |= GPIO_MODER_MODER6_1;    // set alternate mode of port B6
00098         GPIOB->PUPDR &= ~GPIO_PUPDR_PUPDR6;     // reset pull-up/pull-down on port B6
00099         GPIOB->PUPDR |= GPIO_PUPDR_PUPDR6_1;    // set input as pull-down
00100         GPIOB->AFR[0] &= ~(0xF << 4*6);         // reset alternate function of port B6
00101         GPIOB->AFR[0] |= 2 << 4*6;              // set alternate funtion 2 of port B6
00102 
00103         GPIOB->MODER &= ~GPIO_MODER_MODER7;     // reset port B7
00104         GPIOB->MODER |= GPIO_MODER_MODER7_1;    // set alternate mode of port B7
00105         GPIOB->PUPDR &= ~GPIO_PUPDR_PUPDR7;     // reset pull-up/pull-down on port B7
00106         GPIOB->PUPDR |= GPIO_PUPDR_PUPDR7_1;    // set input as pull-down
00107         GPIOB->AFR[0] &= ~0xF0000000;           // reset alternate function of port B7
00108         GPIOB->AFR[0] |= 2 << 4*7;              // set alternate funtion 2 of port B7
00109 
00110         // configure reset and clock control registers
00111 
00112         RCC->APB1RSTR |= RCC_APB1RSTR_TIM4RST;  //reset TIM4 controller
00113         RCC->APB1RSTR &= ~RCC_APB1RSTR_TIM4RST;
00114 
00115         RCC->APB1ENR |= RCC_APB1ENR_TIM4EN;     // TIM4 clock enable
00116 
00117     } else {
00118 
00119         printf("pinmap not found for peripheral\n");
00120     }
00121 
00122     // configure general purpose timer 3 or 4
00123 
00124     TIM->CR1 = 0x0000;          // counter disable
00125     TIM->CR2 = 0x0000;          // reset master mode selection
00126     TIM->SMCR = TIM_SMCR_SMS_1 | TIM_SMCR_SMS_0; // counting on both TI1 & TI2 edges
00127     TIM->CCMR1 = TIM_CCMR1_CC2S_0 | TIM_CCMR1_CC1S_0;
00128     TIM->CCMR2 = 0x0000;        // reset capture mode register 2
00129     TIM->CCER = TIM_CCER_CC2E | TIM_CCER_CC1E;
00130     TIM->CNT = 0x0000;          // reset counter value
00131     TIM->ARR = 0xFFFF;          // auto reload register
00132     TIM->CR1 = TIM_CR1_CEN;     // counter enable
00133 }
00134 
00135 EncoderCounter::~EncoderCounter() {}
00136 
00137 /**
00138  * Resets the counter value to zero.
00139  */
00140 void EncoderCounter::reset()
00141 {
00142 
00143     TIM->CNT = 0x0000;
00144 }
00145 
00146 /**
00147  * Resets the counter value to a given offset value.
00148  * @param offset the offset value to reset the counter to.
00149  */
00150 void EncoderCounter::reset(short offset)
00151 {
00152 
00153     TIM->CNT = -offset;
00154 }
00155 
00156 /**
00157  * Reads the quadrature encoder counter value.
00158  * @return the quadrature encoder counter as a signed 16-bit integer value.
00159  */
00160 short EncoderCounter::read()
00161 {
00162 
00163     return (short)(-TIM->CNT);
00164 }
00165 
00166 /**
00167  * The empty operator is a shorthand notation of the <code>read()</code> method.
00168  */
00169 EncoderCounter::operator short()
00170 {
00171 
00172     return read();
00173 }