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- Added code and script files
- Create a Makefile file - Updated README.md file
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5 files changed

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‎Gpio.cpp‎

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#include "Gpio.h"
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Gpio::Gpio(bool enable_spi) {
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if (this->init_gpio() == NO_ERROR && enable_spi) {
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this->init_spi();
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}
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}
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Gpio::~Gpio() {
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this->close_gpio();
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}
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int Gpio::init_gpio() {
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int errnum = NO_ERROR;
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// Start the BCM2835 Library to access GPIO
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if (!bcm2835_init()) {
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cerr << "bcm2835_init failed (Are you running as root?)" << endl;
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errnum = BCM2835_INIT_ERROR;
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exit(errnum);
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}
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return errnum;
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}
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int Gpio::init_spi() {
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int errnum = NO_ERROR;
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// Enable SPI bus
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if (!bcm2835_spi_begin()) {
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cerr << "bcm2835_spi_begin failed (Are you running as root?)" << endl;
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errnum = BCM2835_INIT_SPI_ERROR;
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exit(errnum);
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}
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return errnum;
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}
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int Gpio::close_gpio() {
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int errnum = NO_ERROR;
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if (!bcm2835_close()) {
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cerr << "bcm2835_close failed (Are you running as root?)" << endl;
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errnum = BCM2835_CLOSE_ERROR;
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exit(errnum);
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}
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return errnum;
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}
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void Gpio::setup_pwm(GpioPwmClock clock) {
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std::uint32_t clock_static = static_cast<std::uint32_t>(clock);
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bcm2835_pwm_set_clock(clock_static);
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}
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void Gpio::setup_pin(GpioPin pin) {
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std::uint8_t funStatic = static_cast<std::uint8_t>(pin.function);
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std::uint8_t pullUpStatic = static_cast<std::uint8_t>(pin.pullUp);
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std::uint8_t pinStatic = static_cast<std::uint8_t>(pin.name);
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Feature feature = getFeature(pin);
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LOG("set_direction(function=%d, pullUp=%d) on pin:%d", unsigned(funStatic), unsigned(pullUpStatic), unsigned(pinStatic));
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if (pin.name != GpioPinName::unknown) {
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// Set function
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if (feature == Feature::io) {
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bcm2835_gpio_fsel(pinStatic, funStatic);
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} else if (feature == Feature::pwm) {
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std::uint8_t channel = get_pwm_channel(pin);
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std::uint8_t mode_static = static_cast<std::uint8_t>(pin.pwmMode);
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std::uint8_t range = pin.pwmRange;
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if (channel >= 0 && pin.pwmMode != GpioPwmMode::unknown) {
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bcm2835_pwm_set_mode(channel, mode_static, 1 /* 1=enable */);
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}
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if (channel >= 0 && range > 0) {
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bcm2835_pwm_set_range(channel, range);
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}
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}
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// if specified set PullUp resistor
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if (pin.pullUp != GpioPullUp::none) {
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LOG("override pull up setting");
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bcm2835_gpio_set_pud(pinStatic, pullUpStatic);
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} else {
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LOG("leave pull up setting as is");
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}
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} else {
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cerr << "setup_pin() pin name not initialised" << endl;
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}
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}
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void Gpio::read(std::list<GpioPin*> pin_list) {
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for (GpioPin *pin : pin_list) {
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uint8_t pin_static = static_cast<std::uint8_t>(pin->name);
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pin->value = bcm2835_gpio_lev(pin_static);
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LOG("read pin:%d value:%d", pin_static, pin->value);
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}
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}
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std::list<GpioPin*> Gpio::get_pins_up(std::list<GpioPin*> pins_to_check) {
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std::list<GpioPin*> switches_pushed = {};
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if (!pins_to_check.empty()) {
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read(pins_to_check);
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for (GpioPin *pin : pins_to_check) {
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// Keep pins up only
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if ((pin->value == 0 && pin->pullUp == GpioPullUp::up) || (pin->value != 0 && pin->pullUp != GpioPullUp::up)) {
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switches_pushed.push_back(pin);
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}
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}
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}
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return switches_pushed;
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}
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void Gpio::write(GpioPin* pin, uint8_t val) {
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std::uint8_t val_static = static_cast<std::uint8_t>(val);
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std::uint8_t pin_static = static_cast<std::uint8_t>(pin->name);
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std::uint8_t channel = get_pwm_channel(*pin);
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if (channel < 0) {
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bcm2835_gpio_write(pin_static, val_static);
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LOG("write pin:%d value:%d", pin_static, val_static);
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} else {
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bcm2835_pwm_set_data(channel, val_static);
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LOG("write PWM pin:%d value:%d", pin_static, val_static);
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}
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pin->value = val_static;
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}
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std::uint8_t Gpio::get_pwm_channel(GpioPin pin) {
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std::uint8_t channel = -1;
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GpioPinName name = pin.name;
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GpioFunction func = pin.function;
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if (getFeature(pin) != Feature::pwm) {
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channel = -1;
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} else if ((name == GpioPinName::gpio13 && func == GpioFunction::alt0) ||
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(name == GpioPinName::gpio19 && func == GpioFunction::alt5)) {
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channel = 1;
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} else if (name == GpioPinName::gpio18 && func == GpioFunction::alt5) {
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channel = 0;
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}
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return channel;
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}
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Feature Gpio::getFeature(GpioPin pin) {
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Feature feature = Feature::unknown;
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GpioPinName name = pin.name;
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GpioFunction func = pin.function;
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if ((name != GpioPinName::unknown && func == GpioFunction::input) ||
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(name != GpioPinName::unknown && func == GpioFunction::output)) {
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feature = Feature::io;
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} else if ((name == GpioPinName::gpio13 && func == GpioFunction::alt0) ||
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(name == GpioPinName::gpio19 && func == GpioFunction::alt5) ||
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(name == GpioPinName::gpio18 && func == GpioFunction::alt5)) {
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feature = Feature::pwm;
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}
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return feature;
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}

‎Gpio.h‎

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#ifndef GPIO_CLASS_H
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#define GPIO_CLASS_H
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#include <string>
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#include <iostream>
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#include <list>
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#include <sstream>
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#include <unistd.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <signal.h>
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#include <bcm2835.h>
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using namespace std;
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#ifdef DEBUG
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#define LOG(...) do { if (DEBUG) { \
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printf(__VA_ARGS__); \
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printf("\n"); \
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}} while (0)
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#else
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#define LOG(...)
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#endif
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// Error codes
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#define NO_ERROR 0
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#define BCM2835_INIT_ERROR -1
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#define BCM2835_INIT_SPI_ERROR -2
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#define BCM2835_CLOSE_ERROR -3
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// Pin names
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enum class GpioPinName: std::uint8_t {
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unknown = 0xff,
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gpio27 = RPI_V2_GPIO_P1_13,
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gpio22 = RPI_V2_GPIO_P1_15,
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gpio10 = RPI_V2_GPIO_P1_19,
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gpio19 = RPI_V2_GPIO_P1_35, /*!< Can be PWM channel 1 in ALT FUN 5 */
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gpio18 = RPI_V2_GPIO_P1_12, /*!< Can be PWM channel 0 in ALT FUN 5 */
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gpio13 = RPI_V2_GPIO_P1_33, /*!< Can be PWM channel 1 in ALT FUN 0 */
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gpio12 = RPI_V2_GPIO_P1_32, /*!< Can be PWM channel 0 in ALT FUN 0 */
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gpio4 = RPI_V2_GPIO_P1_07
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};
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// Functions
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enum class GpioFunction: std::uint8_t {
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unknown = 0xff,
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input = BCM2835_GPIO_FSEL_INPT,
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output = BCM2835_GPIO_FSEL_OUTP,
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alt0 = BCM2835_GPIO_FSEL_ALT0,
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alt1 = BCM2835_GPIO_FSEL_ALT1,
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alt2 = BCM2835_GPIO_FSEL_ALT2,
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alt3 = BCM2835_GPIO_FSEL_ALT3,
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alt4 = BCM2835_GPIO_FSEL_ALT4,
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alt5 = BCM2835_GPIO_FSEL_ALT5
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};
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// Pull up resistor
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enum class GpioPullUp: std::uint8_t {
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none = 0xff,
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off = BCM2835_GPIO_PUD_OFF,
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up = BCM2835_GPIO_PUD_UP,
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down = BCM2835_GPIO_PUD_DOWN
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};
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// PWM clock values
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enum class GpioPwmClock: std::uint32_t {
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KHZ_4_6875 = BCM2835_PWM_CLOCK_DIVIDER_1, /*!< 1 = 4.6875kHz, same as divider 4096 */
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KHZ_9_375 = BCM2835_PWM_CLOCK_DIVIDER_2048, /*!< 2048 = 9.375kHz */
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KHZ_18_75 = BCM2835_PWM_CLOCK_DIVIDER_1024, /*!< 1024 = 18.75kHz */
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KHZ_37_5 = BCM2835_PWM_CLOCK_DIVIDER_512, /*!< 512 = 37.5kHz */
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KHZ_75 = BCM2835_PWM_CLOCK_DIVIDER_256, /*!< 256 = 75kHz */
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KHZ_150 = BCM2835_PWM_CLOCK_DIVIDER_128, /*!< 128 = 150kHz */
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KHZ_300 = BCM2835_PWM_CLOCK_DIVIDER_64, /*!< 64 = 300kHz */
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KHZ_600 = BCM2835_PWM_CLOCK_DIVIDER_32, /*!< 32 = 600.0kHz */
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MHZ_1_2 = BCM2835_PWM_CLOCK_DIVIDER_16, /*!< 16 = 1.2MHz */
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MHZ_2_4 = BCM2835_PWM_CLOCK_DIVIDER_8, /*!< 8 = 2.4MHz */
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MHZ_4_8 = BCM2835_PWM_CLOCK_DIVIDER_4, /*!< 4 = 4.8MHz */
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MHZ_9_6 = BCM2835_PWM_CLOCK_DIVIDER_2 /*!< 2 = 9.6MHz, fastest you can get */
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};
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// PWM modes
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enum class GpioPwmMode: std::uint8_t {
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unknown = 0xff,
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balanced = 0,
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markspace = 1
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};
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// GPIO pin
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struct GpioPin {
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GpioPinName name = GpioPinName::unknown;
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GpioFunction function = GpioFunction::unknown;
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GpioPullUp pullUp = GpioPullUp::none;
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// PWM
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GpioPwmMode pwmMode = GpioPwmMode::unknown;
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std::uint32_t pwmRange = 255;
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std::uint32_t value = 0;
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};
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enum class Feature {
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unknown,
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io,
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pwm,
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spi
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};
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class Gpio {
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public:
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Gpio(bool enable_spi = false);
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~Gpio();
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void setup_pin(GpioPin pin);
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void setup_pwm(GpioPwmClock clock);
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void read(std::list<GpioPin*> pin_list);
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std::list<GpioPin*> get_pins_up(std::list<GpioPin*> pins_to_check);
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void write(GpioPin* pin, std::uint8_t val);
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private:
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int init_gpio();
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int init_spi();
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int close_gpio();
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std::uint8_t get_pwm_channel(GpioPin pin);
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Feature getFeature(GpioPin pin);
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};
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#endif

‎Makefile‎

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CC := g++
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CCFLAGS := -Wall
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DEBUGFLAGS := -DDEBUG
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TARGET := Gpio
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MAINS := $(addsuffix .o, $(TARGET) )
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OBJ := $(MAINS)
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DEPS :=
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.PHONY: all clean
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all: $(TARGET)
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debug: CCFLAGS += $(DEBUGFLAGS)
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debug: $(TARGET)
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clean:
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rm -f $(TARGET)
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$(TARGET): % : %.cpp $(DEPS)
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$(CC) -c -o $@ $< $(CCFLAGS)

‎README.md‎

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# raspberrypi_gpio
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C++ wrapper around BCM2835 library manage the GPIO port of a Raspberry Pi
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# RASPBERRYPI_GPIO
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C++ class wrapping [BCM2835](http://www.airspayce.com/mikem/bcm2835) C library which helps to manage the GPIO port of a Raspberry Pi
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This class has been testred on a Raspberry Pi Zero W only
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# DEPENDENCIES
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## BCM2835 LIBRARY
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To install `BCM2835` library see instructions [here](http://www.airspayce.com/mikem/bcm2835)
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The `bcm2835/install.sh` script helps to download, compile and install the library however there is no guarantee it works on all OS
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# COMPILATION
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To compile this project there is a *Makefile*. Here are the available make commands:
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- `all` - build the project with applying the release configuration
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- `debug` - build the project with applying the debug configuration
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- `clean` - delete all generated files

‎bcm2835/install.sh‎

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#!/bin/bash
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BCM2835="bcm2835-1.62"
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echo "INSTALLING BCM2835 V1.62 LIBRARY TO HOME DIRECTORY..."
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cd ~
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wget http://www.airspayce.com/mikem/bcm2835/${BCM2835}.tar.gz
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if [ -f "${BCM2835}.tar.gz" ]; then
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tar -zvxf ${BCM2835}.tar.gz
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else
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echo "ERROR WHILE DOWNLOADING ${BCM2835} LIBRARY"
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exit -1
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fi
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if [ ! -d ${BCM2835} ]; then
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echo "ERROR WHILE UNCOMPRESSING ${BCM2835}.tar.gz file"
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exit -2
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fi
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echo "COMPILING LIBRARY..."
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cd bcm2835-1.62
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./configure
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make
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echo "INSTALLING LIBRARY..."
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sudo make install
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echo "DONE"

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