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GPIO

Introduction

GPIO (General-Purpose Input/Output) is the abbreviation for General-Purpose Input/Output port. It allows for both output and input to be controlled via software. For input, the default voltage can be configured through pull mode. For output, writing to a register can set the pin to output a high or low potential.

Function List

  1. Initialization — Initialize the driver.

  2. Configure Direction — Set the direction (input or output) of the GPIO pin.

  3. Set Pull Mode — Configure the GPIO pin’s pull-up, pull-down, or floating mode.

  4. Data Read — Read data from the GPIO pin.

  5. Data Write — Write data to the GPIO pin, where 1 represents pulling high and 0 represents pulling low.

  6. Pin Multiplexing — Select the IOMUX pin multiplexing .

  7. Enable Interrupt — Enable GPIO interrupts.

  8. Set Interrupt Mode — Configure the GPIO interrupt mode.

Function Overview

The W800 features 48 GPIO pins, which can be configured for multiplexing through the IO MUX. For specific multiplexing relationships, please refer to the PINMUX section. Among them, OPT1-OPT4 are configured for digital multiplexing, OPT5 is for GPIO, and OPT6-OPT7 are for analog multiplexing. It is important to note that when configured for analog multiplexing, the pin needs to be set to input floating mode.

Main Functions

Initializing GPIO

Before using GPIO, the wm_drv_gpio_init function must be called to initialize the GPIO device. Utilizing wm_device_t, the following is an example code snippet:

wm_device_t *gpio_device;
gpio_device = wm_drv_gpio_init("gpio");

The parameter specifies the device name, which must match the name defined in the device table.

Warning

After initializing GPIO, if wm_drv_gpio_deinit is not called, calling wm_drv_gpio_init again will return NULL.

Configuring Direction

GPIO direction configuration is used to set the pin to either input or output mode. Use the wm_drv_gpio_set_dir function to set the pin direction. Example code is as follows:

wm_drv_gpio_set_dir(WM_GPIO_NUM_0, WM_GPIO_DIR_INPUT);
wm_drv_gpio_set_dir(WM_GPIO_NUM_0, WM_GPIO_DIR_OUTPUT);

The first parameter is the pin number, and the second parameter is the direction, which can be either WM_GPIO_DIR_INPUT or WM_GPIO_DIR_OUTPUT.

Configuring Pull Mode

GPIO pull mode configuration is used to set the pin to pull-up, pull-down, or floating mode. Use the wm_drv_gpio_set_pullmode function to configure the pin pull mode. Here is an example code snippet:

wm_drv_gpio_set_pullmode(WM_GPIO_NUM_0, WM_GPIO_PULL_UP);
wm_drv_gpio_set_pullmode(WM_GPIO_NUM_0, WM_GPIO_PULL_DOWN);

The first parameter is the pin number, and the second parameter is the pull mode, which can be WM_GPIO_PULL_UP, WM_GPIO_PULL_DOWN, or WM_GPIO_FLOAT.

Reading Data

Use the wm_drv_gpio_data_get function to read data from a GPIO pin. This function returns the current level of the pin. Example code is as follows:

int value = wm_drv_gpio_data_get(WM_GPIO_NUM_0);

The parameter is the pin number.

Writing Data

Use the wm_drv_gpio_data_set function to write data to the GPIO pin,setting the pin to high level. Here is an example code snippet:

wm_drv_gpio_data_set(WM_GPIO_NUM_0);

Use the wm_drv_gpio_data_reset function to set the pin to low level. Example code is as follows:

wm_drv_gpio_data_reset(WM_GPIO_NUM_0);

The parameter is the pin number.

Pin Multiplexing Selection

To select the multiplexing function of a GPIO pin using the using the wm_drv_gpio_iomux_func_sel function,the example code is as follows:

wm_gpio_num_t pin = WM_GPIO_NUM_21;
wm_gpio_pin_mux_t func = WM_GPIO_IOMUX_FUN5;

wm_drv_gpio_iomux_func_sel(pin, func);

The first parameter is the pin number, and the second parameter is the function mode, which can be referenced in the table in the function overview or checked in wm_io_mux.h.

Enabling Interrupt

To enable interrupts for a GPIO pin using the wm_drv_gpio_enable_isr function, the example code is as follows:

wm_drv_gpio_enable_isr(WM_GPIO_NUM_21);

The parameter is the pin number.

Disabling Interrupts

To disable interrupts for a GPIO pin using the wm_drv_gpio_disable_isr function, the example code is as follows:

.. code:: c

wm_drv_gpio_disable_isr(WM_GPIO_NUM_21);

The parameter is the pin number.

Setting Interrupt Mode

Configuring the interrupt trigger mode for a GPIO pin using the wm_drv_gpio_set_intr_mode function involves selecting from options such as falling edge trigger, rising edge trigger, double edge trigger, low level trigger, and high level trigger. The example code is provided below:

wm_drv_gpio_set_intr_mode(WM_GPIO_NUM_21, WM_GPIO_IRQ_TRIG_HIGH_LEVEL);

The first parameter is the pin number, while the second parameter is the interrupt mode, which can be WM_GPIO_IRQ_TRIG_FALLING_EDGE, WM_GPIO_IRQ_TRIG_RISING_EDGE, WM_GPIO_IRQ_TRIG_DOUBLE_EDGE, WM_GPIO_IRQ_TRIG_LOW_LEVEL, or WM_GPIO_IRQ_TRIG_HIGH_LEVEL.

Application Example

For a basic example of GPIO using, please refer to: examples/peripheral/gpio

API Reference

To find GPIO-related APIs, please refer to: