GPIO

This section provides introduction to the General Purpose Input Output (GPIO) APIs, including terms and acronyms, features, architecture, how to use APIs, the GPIO function groups, enums, structures and functions. More...

Overview

This section provides introduction to the General Purpose Input Output (GPIO) APIs, including terms and acronyms, features, architecture, how to use APIs, the GPIO function groups, enums, structures and functions.

Terms and acronyms

Terms	Details
GPIO	General Purpose Input Output is a generic pin on an integrated circuit defined as an input or output pin, and controlled by the user at run time. For more information, please refer to General Purpose Input Output in Wikipedia .

Supported features

• Support GPIO and peripheral operating modes.
  GPIO operates in various modes depending on the user configuration:
  • GPIO mode: In this mode the pin is programmed as a software controlled input or output by reading or writing to and from the corresponding data register. Both input data and output data can be digital low or digital high.
    
  • Peripheral mode: In this mode the pin operates as an embedded peripheral. The microcontroller pin connects the peripheral through a multiplexer to only one alternate function at a time. The peripheral module must configure the pinmux to the corresponding pin before it is used. Two ways to apply pinmux configuration: call hal_pinmux_set_function() or configure the Easy pinmux tool (EPT), a software tool providing a graphical user interface for pinmux configuration. For more information about alternate functions of the pins, please refer to hal_pinmux_define.h.
    
• Call hal_pinmux_set_function() to set the pin mode and call hal_gpio_set_direction() to set the direction of GPIO. If the pin is in GPIO mode, call the hal_gpio_get_input() to get input data of the pin, and hal_gpio_set_output() to set data to output.
  
• Support toggle function.
  The toggle function inverses output data of pins for every function call.
  Call hal_gpio_toggle_pin() to toggle the output data of the target pin.
  
• Support pull-up and pull-down functions.
  The pull-up and pull-down functions define the input state of a pin if no signal source is connected. Both the pull-up and pull-down functions are implemented using resistors. Set the pull state of the target pin by configuring the GPIO registers.
  Call hal_gpio_pull_down() to set the pin to pull down state and hal_gpio_pull_up() to set the pin to pull up state.

Software architecture of GPIO

The GPIO driver supports two modes of operation as described below.

1. GPIO mode architecture: If the pin is specified to operate in GPIO mode, it can be programmed in input and output directions. If the direction is configured as output through direction register, the data written to the output register will be output on the pin, the output data register is also accessible while an access to the output data register only gets the last written value. The output pin is push-pull type by default, push-pull output here means a type of electronic circuit that uses a pair of active devices that alternately supply current to, or absorb current from, a connected load. Push-pull outputs are present in TTL and CMOS digital logic circuits and in some types of amplifiers, and are usually implemented as a complementary pair of transistors, one dissipating or sinking current from the load to ground or a negative power supply, and the other supplying or sourcing current to the load from a positive power supply. If the direction is configured as input, the data present on the pin is received from an input data register. Unlike the output circuit, the Schmitt trigger and pull-up and pull-down resistors on the input circuit. Among them, Schmitt trigger is an active circuit which converts an analog input signal to a digital output signal. The pull-up and pull-down resistors help to set the target pin to the default voltage level (high or low) when the target pin is not connected to the external source.
   
2. Peripheral mode architecture : The pins operate in one of several onboard peripheral modes based on multiplexer settings. It can only operate in one mode at a time to avoid conflict between peripherals sharing the same pin.
   

How to use this driver

• GPIO mode.
• Step 1. Call hal_gpio_init() to initialize the pin.
• Step 2. Call hal_pinmux_set_function() to configure the pin to operate in GPIO mode.
• Step 3. Call hal_gpio_set_direction() to configure the direction of GPIO.
• Step 4. Call hal_gpio_set_output() to set the data into output direction.
• Step 5. Call hal_gpio_deinit() to deinitialize the pin.
• sample code:

  void gpio_application(void)
  {
  
    hal_gpio_init(gpio_pin);
    hal_pinmux_set_function(gpio_pin, function_index); // Set the pin to operate in GPIO mode.
    hal_gpio_set_direction(gpio_pin, HAL_GPIO_DIRECTION_OUTPUT);
    hal_gpio_set_output(gpio_pin, HAL_GPIO_DATA_HIGH);
    hal_gpio_deinit(gpio_pin);
  }

Peripheral mode.

• Step 1. Call hal_gpio_init() to initialize the pin.
• Step 2. Call hal_pinmux_set_function() to configure the pin to operate in peripheral mode.
• Step 3. Call hal_gpio_deinit() to deinitialize the pin.
• sample code:

  void gpio_application(void)
  {
    hal_gpio_init(gpio_pin);
    // For more information about pinmux, please refer to hal_pinmux_define.h
    hal_pinmux_set_function(gpio_pin, function_index);   // Set the pin to the peripheral mode as defined in function_index.
    hal_gpio_deinit(gpio_pin);
   }

  
  

Functions
hal_gpio_status_t	hal_gpio_init (hal_gpio_pin_t gpio_pin)
	This function initializes the GPIO hardware with basic functionality. More...
hal_gpio_status_t	hal_gpio_deinit (hal_gpio_pin_t gpio_pin)
	This function deinitializes the GPIO hardware to its default status. More...
hal_pinmux_status_t	hal_pinmux_set_function (hal_gpio_pin_t gpio_pin, uint8_t function_index)
	This function configures the pinmux of target GPIO. More...
hal_gpio_status_t	hal_gpio_get_input (hal_gpio_pin_t gpio_pin, hal_gpio_data_t *gpio_data)
	This function gets the input data of target GPIO when the direction of the GPIO is input. More...
hal_gpio_status_t	hal_gpio_set_output (hal_gpio_pin_t gpio_pin, hal_gpio_data_t gpio_data)
	This function sets the output data of the target GPIO. More...
hal_gpio_status_t	hal_gpio_get_output (hal_gpio_pin_t gpio_pin, hal_gpio_data_t *gpio_data)
	This function gets the output data of the target GPIO when the direction of the GPIO is output. More...
hal_gpio_status_t	hal_gpio_set_direction (hal_gpio_pin_t gpio_pin, hal_gpio_direction_t gpio_direction)
	This function sets the direction of the target GPIO. More...
hal_gpio_status_t	hal_gpio_get_direction (hal_gpio_pin_t gpio_pin, hal_gpio_direction_t *gpio_direction)
	This function gets the direction of the target GPIO. More...
hal_gpio_status_t	hal_gpio_toggle_pin (hal_gpio_pin_t gpio_pin)
	This function toggles the output data of the target GPIO when the direction of the pin is output. More...
hal_gpio_status_t	hal_gpio_pull_up (hal_gpio_pin_t gpio_pin)
	This function sets the target GPIO to pull-up state, after this function, the input data of the target pin will be equivalent to high if the pin is disconnected. More...
hal_gpio_status_t	hal_gpio_pull_down (hal_gpio_pin_t gpio_pin)
	This function sets the target GPIO to the pull-down state, after this function, the input data of the target pin will be equivalent to low if the pin is disconnected. More...
hal_gpio_status_t	hal_gpio_disable_pull (hal_gpio_pin_t gpio_pin)
	This function disables pull-up or pull-down of the target GPIO. More...
hal_gpio_status_t	hal_gpio_set_driving_current (hal_gpio_pin_t gpio_pin, hal_gpio_driving_current_t driving)
	This function sets the driving current of the target GPIO. More...
hal_gpio_status_t	hal_gpio_get_driving_current (hal_gpio_pin_t gpio_pin, hal_gpio_driving_current_t *driving)
	This function gets the driving current of the target GPIO. More...

Modules
	Enum

Function Documentation

hal_gpio_status_t hal_gpio_deinit

(

hal_gpio_pin_t

gpio_pin

)

This function deinitializes the GPIO hardware to its default status.

The target pin must be deinitialized if not used.

Parameters

[in]

gpio_pin

specifies pin number to deinitialize.

Returns

To indicate whether this function call is successful or not. If the return value is HAL_GPIO_STATUS_OK, the operation completed successfully. If the return value is HAL_GPIO_STATUS_ERROR_PIN, invalid input pin number, the parameter must be verified. If the return value is HAL_GPIO_STATUS_ERROR, the operation failed.

Note

Warning

hal_gpio_status_t hal_gpio_disable_pull

(

hal_gpio_pin_t

gpio_pin

)

This function disables pull-up or pull-down of the target GPIO.

This function operates on the pins with one pull-up and one pull-down resistors.

Parameters

[in]

gpio_pin

specifies the pin number to set.

Returns

To indicate whether this function call is successful or not. If the return value is HAL_GPIO_STATUS_OK, the operation completed successfully. If the return value is HAL_GPIO_STATUS_ERROR_PIN, invalid input pin number, the parameter must be verified. If the return value is HAL_GPIO_STATUS_ERROR, the operation failed.

Note

Warning

Example

hal_gpio_status_t ret;
hal_pinmux_status_t ret_pinmux_status;

ret = hal_gpio_init(gpio_pin);
ret_pinmux_status = hal_pinmux_set_function(gpio_pin, function_index); // Set the pin to GPIO mode.
ret = hal_gpio_set_direction(gpio_pin, HAL_GPIO_DIRECTION_INPUT);
ret = hal_gpio_pull_down(gpio_pin);
ret = hal_gpio_disable_pull(gpio_pin);   // Pull state of the target GPIO is disabled.
ret = hal_gpio_deinit(gpio_pin);

hal_gpio_status_t hal_gpio_get_direction	(	hal_gpio_pin_t	gpio_pin,
		hal_gpio_direction_t *	gpio_direction
	)

This function gets the direction of the target GPIO.

Parameters

[in]	gpio_pin	specifies the pin number to operate.
[in]	gpio_direction	is the direction of target GPIO, the direction can be input or output.

Returns

To indicate whether this function call is successful or not. If the return value is HAL_GPIO_STATUS_OK, the operation completed successfully. If the return value is HAL_GPIO_STATUS_INVALID_PARAMETER, a wrong parameter (except for pin number) is given, the parameter must be verified. If the return value is HAL_GPIO_STATUS_ERROR_PIN, invalid input pin number, the parameter must be verified. If the return value is HAL_GPIO_STATUS_ERROR, the operation failed.

Note

Warning

hal_gpio_status_t hal_gpio_get_driving_current	(	hal_gpio_pin_t	gpio_pin,
		hal_gpio_driving_current_t *	driving
	)

This function gets the driving current of the target GPIO.

Parameters

[in]	gpio_pin	specifies the pin number to configure.
[in]	driving	specifies the driving current to be set to target GPIO.

Returns

To indicate whether this function call is successful or not. If the return value is HAL_GPIO_STATUS_OK, the operation completed successfully. If the return value is HAL_GPIO_STATUS_ERROR_PIN, the operation failed.

Note

Warning

Example

hal_gpio_status_t ret;
hal_pinmux_status_t ret_pinmux_status;
hal_gpio_driving_current_t *driving;

ret = hal_gpio_init(gpio_pin);
ret = hal_gpio_get_driving(gpio_pin, &driving);
ret = hal_gpio_deinit(gpio_pin);

hal_gpio_status_t hal_gpio_get_input	(	hal_gpio_pin_t	gpio_pin,
		hal_gpio_data_t *	gpio_data
	)

This function gets the input data of target GPIO when the direction of the GPIO is input.

Parameters

[in]	gpio_pin	specifies the pin number to operate.
[in]	gpio_data	is the input data received from the target GPIO.

Returns

To indicate whether this function call is successful or not. If the return value is HAL_GPIO_STATUS_OK, the operation completed successfully. If the return value is HAL_GPIO_STATUS_INVALID_PARAMETER, a wrong parameter (except for pin number) is given, the parameter must be verified. If the return value is HAL_GPIO_STATUS_ERROR_PIN, invalid input pin number, the parameter must be verified. If the return value is HAL_GPIO_STATUS_ERROR, the operation failed.

Note

Warning

hal_gpio_status_t hal_gpio_get_output	(	hal_gpio_pin_t	gpio_pin,
		hal_gpio_data_t *	gpio_data
	)

This function gets the output data of the target GPIO when the direction of the GPIO is output.

Parameters

[in]	gpio_pin	specifies the pin number to operate.
[in]	gpio_data	is output data of the target GPIO.

Returns

To indicate whether this function call is successful or not. If the return value is HAL_GPIO_STATUS_OK, the operation completed successfully. If the return value is HAL_GPIO_STATUS_INVALID_PARAMETER, a wrong parameter (except for pin number) is given, the parameter must be verified. If the return value is HAL_GPIO_STATUS_ERROR_PIN, invalid input pin number, the parameter must be verified. If the return value is HAL_GPIO_STATUS_ERROR, the operation failed.

Note

Warning

hal_gpio_status_t hal_gpio_init

(

hal_gpio_pin_t

gpio_pin

)

This function initializes the GPIO hardware with basic functionality.

The target pin must be initialized before use.

Parameters

[in]

gpio_pin

specifies the pin number to initialize.

Returns

To indicate whether this function call is successful or not. If the return value is HAL_GPIO_STATUS_OK, the operation completed successfully. If the return value is HAL_GPIO_STATUS_ERROR_PIN, invalid input pin number, the parameter must be verified. If the return value is HAL_GPIO_STATUS_ERROR, the operation failed.

Note

Warning

hal_gpio_status_t hal_gpio_pull_down

(

hal_gpio_pin_t

gpio_pin

)

This function sets the target GPIO to the pull-down state, after this function, the input data of the target pin will be equivalent to low if the pin is disconnected.

This function operates on the pin with one pull-down resistor.

Parameters

[in]

gpio_pin

specifies the pin number to set.

Returns

To indicate whether this function call is successful or not. If the return value is HAL_GPIO_STATUS_OK, the operation completed successfully. If the return value is HAL_GPIO_STATUS_ERROR_PIN, invalid input pin number, the parameter must be verified. If the return value is HAL_GPIO_STATUS_ERROR, the operation failed.

Note

Warning

Example

hal_gpio_status_t ret;
hal_pinmux_status_t ret_pinmux_status;

ret = hal_gpio_init(gpio_pin);
ret_pinmux_status = hal_pinmux_set_function(gpio_pin, function_index); // Set the pin to GPIO mode.
ret = hal_gpio_set_direction(gpio_pin, HAL_GPIO_DIRECTION_INPUT);
ret = hal_gpio_pull_down(gpio_pin);   // Pull state of the target GPIO is set to pull-down.
ret = hal_gpio_deinit(gpio_pin);

hal_gpio_status_t hal_gpio_pull_up

(

hal_gpio_pin_t

gpio_pin

)

This function sets the target GPIO to pull-up state, after this function, the input data of the target pin will be equivalent to high if the pin is disconnected.

This function operates on the pins with only one pull-up resistor.

Parameters

[in]

gpio_pin

specifies the pin number to set.

Returns

To indicate whether this function call is successful or not. If the return value is HAL_GPIO_STATUS_OK, the operation completed successfully. If the return value is HAL_GPIO_STATUS_ERROR_PIN, invalid input pin number, the parameter must be verified. If the return value is HAL_GPIO_STATUS_ERROR, the operation failed.

Note

Warning

Example

hal_gpio_status_t ret;
hal_pinmux_status_t ret_pinmux_status;

ret = hal_gpio_init(gpio_pin);
ret_pinmux_status = hal_pinmux_set_function(gpio_pin, function_index); // Set the pin to GPIO mode.
ret = hal_gpio_set_direction(gpio_pin, HAL_GPIO_DIRECTION_INPUT);
ret = hal_gpio_pull_up(gpio_pin);   // Pull state of the target GPIO is set to pull-up.
ret = hal_gpio_deinit(gpio_pin);

hal_gpio_status_t hal_gpio_set_direction	(	hal_gpio_pin_t	gpio_pin,
		hal_gpio_direction_t	gpio_direction
	)

This function sets the direction of the target GPIO.

Parameters

[in]	gpio_pin	specifies the pin number to set.
[in]	gpio_direction	is the direction of the target GPIO, the direction can be input or output.

Returns

To indicate whether this function call is successful or not. If the return value is HAL_GPIO_STATUS_OK, the operation completed successfully. If the return value is HAL_GPIO_STATUS_INVALID_PARAMETER, a wrong parameter (except for pin number) is given, the parameter must be verified. If the return value is HAL_GPIO_STATUS_ERROR_PIN, invalid input pin number, the parameter must be verified. If the return value is HAL_GPIO_STATUS_ERROR, the operation failed.

Note

Warning

hal_gpio_status_t hal_gpio_set_driving_current	(	hal_gpio_pin_t	gpio_pin,
		hal_gpio_driving_current_t	driving
	)

This function sets the driving current of the target GPIO.

Parameters

[in]	gpio_pin	specifies the pin number to configure.
[in]	driving	specifies the driving current to set to target GPIO.

Returns

To indicate whether this function call is successful or not. If the return value is HAL_GPIO_STATUS_OK, the operation completed successfully. If the return value is HAL_GPIO_STATUS_ERROR_PIN, the operation failed.

Note

Warning

Example

hal_gpio_status_t ret;
hal_pinmux_status_t ret_pinmux_status;

ret = hal_gpio_init(gpio_pin);
ret = hal_gpio_set_driving(gpio_pin, HAL_GPIO_DRIVING_16MA);
ret = hal_gpio_deinit(gpio_pin);

hal_gpio_status_t hal_gpio_set_output	(	hal_gpio_pin_t	gpio_pin,
		hal_gpio_data_t	gpio_data
	)

This function sets the output data of the target GPIO.

Parameters

[in]	gpio_pin	specifies the pin number to operate.
[in]	gpio_data	is the output data of the target GPIO.

Returns

To indicate whether this function call is successful or not. If the return value is HAL_GPIO_STATUS_OK, the operation completed successfully. If the return value is HAL_GPIO_STATUS_INVALID_PARAMETER, a wrong parameter (except for pin number) is given, the parameter must be verified. If the return value is HAL_GPIO_STATUS_ERROR_PIN, invalid input pin number, the parameter must be verified. If the return value is HAL_GPIO_STATUS_ERROR, the operation failed.

Note

Warning

hal_gpio_status_t hal_gpio_toggle_pin

(

hal_gpio_pin_t

gpio_pin

)

This function toggles the output data of the target GPIO when the direction of the pin is output.

After this function, the output data of the target GPIO will be inversed.

Parameters

[in]

gpio_pin

specifies the pin number to toggle.

Returns

To indicate whether this function call is successful or not. If the return value is HAL_GPIO_STATUS_OK, the operation completed successfully. If the return value is HAL_GPIO_STATUS_ERROR_PIN, invalid input pin number, the parameter must be verified. If the return value is HAL_GPIO_STATUS_ERROR, the operation failed.

Note

Warning

Example

hal_gpio_status_t ret;
hal_pinmux_status_t ret_pinmux_status;

ret = hal_gpio_init(gpio_pin);
ret_pinmux_status = hal_pinmux_set_function(gpio_pin, function_index); // Set the pin to GPIO mode.
ret = hal_gpio_set_direction(gpio_pin, HAL_GPIO_DIRECTION_OUTPUT);
ret = hal_gpio_set_output(gpio_pin, HAL_GPIO_DATA_HIGH);
ret = hal_gpio_toggle_pin(gpio_pin);  // Output data of gpio_pin will be toggled to low from high.
ret = hal_gpio_deinit(gpio_pin);

hal_pinmux_status_t hal_pinmux_set_function	(	hal_gpio_pin_t	gpio_pin,
		uint8_t	function_index
	)

This function configures the pinmux of target GPIO.

Pin Multiplexer (pinmux) connects the pin and the onboard peripherals, so the pin will operate in a specific mode once the pin is programmed to a peripheral's function. The alternate functions of every pin are provided in hal_pinmux_define.h.

Parameters

[in]	gpio_pin	specifies the pin number to configure.
[in]	function_index	specifies the function for the pin.

Returns

To indicate whether this function call is successful or not. If the return value is HAL_PINMUX_STATUS_OK, the operation completed successfully. If the return value is HAL_PINMUX_STATUS_INVALID_FUNCTION, a wrong alternate function is given, the parameter must be verified. If the return value is HAL_PINMUX_STATUS_ERROR_PORT, invalid input pin number, the parameter must be verified. If the return value is HAL_PINMUX_STATUS_ERROR, the operation failed.

Note

Warning