GPIO Public APIs

Functions
void	gpio_init (GPIO_CFG_ts *gpio_cfg)
	Initializes a GPIO pin according to the given configuration.
void	gpio_deinit (GPIO_REGDEF_ts const *gpio_port)
	Deinitializes a GPIO port by resetting its registers to reset values.
void	gpio_write (GPIO_REGDEF_ts *gpio_port, uint8_t gpio_pin, PIN_STATUS_te pin_status)
	Drives a GPIO output pin high or low.
PIN_STATUS_te	gpio_read (GPIO_REGDEF_ts const *gpio_port, uint8_t gpio_pin)
	Reads the current logic level of a GPIO input pin.
void	gpio_clear_interrupt (EXTI_LINES_te exti_line)
	Clears the EXTI pending flag for the given interrupt line.
void	gpio_get_name (GPIO_REGDEF_ts const *gpio_port, char *name)
	Returns the name string of a GPIO port.

Detailed Description

Function Documentation

gpio_init()

void gpio_init

(

GPIO_CFG_ts *

gpio_cfg

)

Initializes a GPIO pin according to the given configuration.

See also

gpio_init

Definition at line 29 of file stm32f401re_gpio.c.

                                      {
    // Enable the clock for the GPIO peripheral
    gpio_set_pclk(gpio_cfg->port, ENABLE);
 
    // Configure GPIO output type
    gpio_cfg->port->GPIO_OTYPER &= ~(0b1 << gpio_cfg->pin);
    gpio_cfg->port->GPIO_OTYPER |= gpio_cfg->output_type << gpio_cfg->pin;
 
    // Configure GPIO speed
    gpio_cfg->port->GPIO_OSPEEDR &= ~(0b11 << gpio_cfg->pin * 2);
    gpio_cfg->port->GPIO_OSPEEDR |= gpio_cfg->output_speed << gpio_cfg->pin * 2;
 
    // Configure GPIO pull-up pull-down
    gpio_cfg->port->GPIO_PUPDR &= ~(0b11 << gpio_cfg->pin * 2);
    gpio_cfg->port->GPIO_PUPDR |= gpio_cfg->pull_mode << gpio_cfg->pin * 2;
 
    // Configure GPIO alternate function (2 bits per pin in AFR[0] for pins 0-7, AFR[1] for pins 8-15)
    uint32_t afr_index = gpio_cfg->pin >> 3;        // pin / 8 selects AFR[0] or AFR[1]
    uint32_t afr_shift = (gpio_cfg->pin & 0x7) * 4; // (pin % 8) * 4 gives the bit offset
 
    gpio_cfg->port->GPIO_AFR[afr_index] &= ~(0xFu << afr_shift);
    gpio_cfg->port->GPIO_AFR[afr_index] |= ((uint32_t)gpio_cfg->alternate_function << afr_shift);
 
    // Configure GPIO mode
    if(gpio_cfg->mode != GPIO_MODE_INTERRUPT) {
        gpio_cfg->port->GPIO_MODER &= ~(0b11 << gpio_cfg->pin * 2);
        gpio_cfg->port->GPIO_MODER |= gpio_cfg->mode << gpio_cfg->pin * 2;
    }
    else {
        // Enable the peripheral clock for SYSCFG
        RCC->RCC_APB2ENR |= (0b1 << 14);
 
        // Route the GPIO pin to the EXTI line via SYSCFG_EXTICRx
        if(gpio_cfg->pin < 4) {
            SYSCFG->SYSCFG_EXTICR1 &= ~(0b1111 << gpio_cfg->pin * 4);
            SYSCFG->SYSCFG_EXTICR1 |= (get_syscfg_code(gpio_cfg->port)) << gpio_cfg->pin * 4;
        }
        else if(gpio_cfg->pin < 8) {
            SYSCFG->SYSCFG_EXTICR2 &= ~(0b1111 << (gpio_cfg->pin - 4) * 4);
            SYSCFG->SYSCFG_EXTICR2 |= (get_syscfg_code(gpio_cfg->port)) << (gpio_cfg->pin - 4) * 4;
        }
        else if(gpio_cfg->pin < 12) {
            SYSCFG->SYSCFG_EXTICR3 &= ~(0b1111 << (gpio_cfg->pin - 8) * 4);
            SYSCFG->SYSCFG_EXTICR3 |= (get_syscfg_code(gpio_cfg->port)) << (gpio_cfg->pin - 8) * 4;
        }
        else {
            SYSCFG->SYSCFG_EXTICR4 &= ~(0b1111 << (gpio_cfg->pin - 12) * 4);
            SYSCFG->SYSCFG_EXTICR4 |= (get_syscfg_code(gpio_cfg->port)) << (gpio_cfg->pin - 12) * 4;
        }
 
        // Unmask the EXTI line for this pin
        EXTI->EXTI_IMR |= 0b1 << gpio_cfg->pin;
 
        // Configure edge trigger
        switch(gpio_cfg->interrupt_trigger) {
            case GPIO_INTERRUPT_TRIGGER_RE:
                EXTI->EXTI_RTSR |= 0b1 << gpio_cfg->pin;
                break;
            case GPIO_INTERRUPT_TRIGGER_FE:
                EXTI->EXTI_FTSR |= 0b1 << gpio_cfg->pin;
                break;
            case GPIO_INTERRUPT_TRIGGER_RFE:
                EXTI->EXTI_RTSR |= 0b1 << gpio_cfg->pin;
                EXTI->EXTI_FTSR |= 0b1 << gpio_cfg->pin;
                break;
        }
 
        // Enable the corresponding NVIC interrupt line
        uint8_t exti_position = get_exti_position(gpio_cfg);
        nvic_set_interrupt(exti_position, ENABLE);
    }
}

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gpio_deinit()

void gpio_deinit

(

GPIO_REGDEF_ts const *

gpio_port

)

Deinitializes a GPIO port by resetting its registers to reset values.

See also

gpio_deinit

Definition at line 103 of file stm32f401re_gpio.c.

                                                  {
    if(gpio_port == GPIOA) {
        rcc_reset_periph_ahb1(RCC_AHB1RSTR_GPIOARST);
    }
    else if(gpio_port == GPIOB) {
        rcc_reset_periph_ahb1(RCC_AHB1RSTR_GPIOBRST);
    }
    else if(gpio_port == GPIOC) {
        rcc_reset_periph_ahb1(RCC_AHB1RSTR_GPIOCRST);
    }
    else if(gpio_port == GPIOD) {
        rcc_reset_periph_ahb1(RCC_AHB1RSTR_GPIODRST);
    }
    else if(gpio_port == GPIOE) {
        rcc_reset_periph_ahb1(RCC_AHB1RSTR_GPIOERST);
    }
    else if(gpio_port == GPIOH) {
        rcc_reset_periph_ahb1(RCC_AHB1RSTR_GPIOHRST);
    }
 
    gpio_set_pclk(gpio_port, DISABLE);
}

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gpio_write()

void gpio_write	(	GPIO_REGDEF_ts *	gpio_port,
		uint8_t	gpio_pin,
		PIN_STATUS_te	pin_status )

Drives a GPIO output pin high or low.

See also

gpio_write

Definition at line 127 of file stm32f401re_gpio.c.

                                                                                       {
    switch(pin_status) {
        case HIGH:
            gpio_port->GPIO_ODR |= (0x1 << gpio_pin);
            break;
        case LOW:
            gpio_port->GPIO_ODR &= ~(0x1 << gpio_pin);
            break;
    }
}

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gpio_read()

PIN_STATUS_te gpio_read	(	GPIO_REGDEF_ts const *	gpio_port,
		uint8_t	gpio_pin )

Reads the current logic level of a GPIO input pin.

See also

gpio_read

Definition at line 139 of file stm32f401re_gpio.c.

                                                                           {
    PIN_STATUS_te status = (gpio_port->GPIO_IDR >> gpio_pin) & 0x1;
    return status;
}

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gpio_clear_interrupt()

void gpio_clear_interrupt

(

EXTI_LINES_te

exti_line

)

Clears the EXTI pending flag for the given interrupt line.

See also

gpio_clear_interrupt

Definition at line 145 of file stm32f401re_gpio.c.

                                                   {
    EXTI->EXTI_PR = 0x1 << exti_line;
}

gpio_get_name()

void gpio_get_name	(	GPIO_REGDEF_ts const *	gpio_port,
		char *	name )

Returns the name string of a GPIO port.

Returns the name string of a GPIO port (e.g. "GPIOA").

See also

gpio_get_name

Definition at line 150 of file stm32f401re_gpio.c.

                                                                {
    const char gpio[] = "GPIO";
    uint8_t gpio_len = get_str_len(gpio);
    uint8_t pos_counter = 0;
 
    while(pos_counter < gpio_len) {
        name[pos_counter] = gpio[pos_counter];
        pos_counter++;
    }
 
    if(gpio_port == GPIOA)      name[pos_counter] = 'A';
    else if(gpio_port == GPIOB) name[pos_counter] = 'B';
    else if(gpio_port == GPIOC) name[pos_counter] = 'C';
    else if(gpio_port == GPIOD) name[pos_counter] = 'D';
    else if(gpio_port == GPIOE) name[pos_counter] = 'E';
    else if(gpio_port == GPIOH) name[pos_counter] = 'H';
    pos_counter++;
 
    name[pos_counter] = '\0';
}

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