GPIO & RTC GPIO¶
Overview¶
The ESP32 chip features 40 physical GPIO pads. Some GPIO pads cannot be used or do not have the corresponding pin on the chip package(refer to technical reference manual). Each pad can be used as a general purpose I/O or can be connected to an internal peripheral signal.
- Note that GPIO6-11 are usually used for SPI flash.
- GPIO34-39 can only be set as input mode and do not have software pullup or pulldown functions.
There is also separate “RTC GPIO” support, which functions when GPIOs are routed to the “RTC” low-power and analog subsystem. These pin functions can be used when in deep sleep, when the Ultra Low Power co-processor is running, or when analog functions such as ADC/DAC/etc are in use.
Application Example¶
GPIO output and input interrupt example: peripherals/gpio.
API Reference - Normal GPIO¶
Header File¶
Functions¶
-
esp_err_t
gpio_config
(const gpio_config_t *pGPIOConfig)¶ GPIO common configuration.
Configure GPIO’s Mode,pull-up,PullDown,IntrType
- Return
- ESP_OK success
- ESP_ERR_INVALID_ARG Parameter error
- Parameters
pGPIOConfig
: Pointer to GPIO configure struct
-
esp_err_t
gpio_set_intr_type
(gpio_num_t gpio_num, gpio_int_type_t intr_type)¶ GPIO set interrupt trigger type.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG Parameter error
- Parameters
gpio_num
: GPIO number. If you want to set the trigger type of e.g. of GPIO16, gpio_num should be GPIO_NUM_16 (16);intr_type
: Interrupt type, select from gpio_int_type_t
-
esp_err_t
gpio_intr_enable
(gpio_num_t gpio_num)¶ Enable GPIO module interrupt signal.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG Parameter error
- Parameters
gpio_num
: GPIO number. If you want to enable an interrupt on e.g. GPIO16, gpio_num should be GPIO_NUM_16 (16);
-
esp_err_t
gpio_intr_disable
(gpio_num_t gpio_num)¶ Disable GPIO module interrupt signal.
- Return
- ESP_OK success
- ESP_ERR_INVALID_ARG Parameter error
- Parameters
gpio_num
: GPIO number. If you want to disable the interrupt of e.g. GPIO16, gpio_num should be GPIO_NUM_16 (16);
-
esp_err_t
gpio_set_level
(gpio_num_t gpio_num, uint32_t level)¶ GPIO set output level.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG GPIO number error
- Parameters
gpio_num
: GPIO number. If you want to set the output level of e.g. GPIO16, gpio_num should be GPIO_NUM_16 (16);level
: Output level. 0: low ; 1: high
-
int
gpio_get_level
(gpio_num_t gpio_num)¶ GPIO get input level.
- Return
- 0 the GPIO input level is 0
- 1 the GPIO input level is 1
- Parameters
gpio_num
: GPIO number. If you want to get the logic level of e.g. pin GPIO16, gpio_num should be GPIO_NUM_16 (16);
-
esp_err_t
gpio_set_direction
(gpio_num_t gpio_num, gpio_mode_t mode)¶ GPIO set direction.
Configure GPIO direction,such as output_only,input_only,output_and_input
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG GPIO error
- Parameters
gpio_num
: Configure GPIO pins number, it should be GPIO number. If you want to set direction of e.g. GPIO16, gpio_num should be GPIO_NUM_16 (16);mode
: GPIO direction
-
esp_err_t
gpio_set_pull_mode
(gpio_num_t gpio_num, gpio_pull_mode_t pull)¶ Configure GPIO pull-up/pull-down resistors.
Only pins that support both input & output have integrated pull-up and pull-down resistors. Input-only GPIOs 34-39 do not.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG : Parameter error
- Parameters
gpio_num
: GPIO number. If you want to set pull up or down mode for e.g. GPIO16, gpio_num should be GPIO_NUM_16 (16);pull
: GPIO pull up/down mode.
-
esp_err_t
gpio_wakeup_enable
(gpio_num_t gpio_num, gpio_int_type_t intr_type)¶ Enable GPIO wake-up function.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG Parameter error
- Parameters
gpio_num
: GPIO number.intr_type
: GPIO wake-up type. Only GPIO_INTR_LOW_LEVEL or GPIO_INTR_HIGH_LEVEL can be used.
-
esp_err_t
gpio_wakeup_disable
(gpio_num_t gpio_num)¶ Disable GPIO wake-up function.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG Parameter error
- Parameters
gpio_num
: GPIO number
-
esp_err_t
gpio_isr_register
(void (*fn)(void *), void *arg, int intr_alloc_flags, gpio_isr_handle_t *handle, )¶ Register GPIO interrupt handler, the handler is an ISR. The handler will be attached to the same CPU core that this function is running on.
This ISR function is called whenever any GPIO interrupt occurs. See the alternative gpio_install_isr_service() and gpio_isr_handler_add() API in order to have the driver support per-GPIO ISRs.
To disable or remove the ISR, pass the returned handle to the interrupt allocation functions.
- Parameters
fn
: Interrupt handler function.intr_alloc_flags
: Flags used to allocate the interrupt. One or multiple (ORred) ESP_INTR_FLAG_* values. See esp_intr_alloc.h for more info.arg
: Parameter for handler functionhandle
: Pointer to return handle. If non-NULL, a handle for the interrupt will be returned here.
- Return
- ESP_OK Success ;
- ESP_ERR_INVALID_ARG GPIO error
-
esp_err_t
gpio_pullup_en
(gpio_num_t gpio_num)¶ Enable pull-up on GPIO.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG Parameter error
- Parameters
gpio_num
: GPIO number
-
esp_err_t
gpio_pullup_dis
(gpio_num_t gpio_num)¶ Disable pull-up on GPIO.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG Parameter error
- Parameters
gpio_num
: GPIO number
-
esp_err_t
gpio_pulldown_en
(gpio_num_t gpio_num)¶ Enable pull-down on GPIO.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG Parameter error
- Parameters
gpio_num
: GPIO number
-
esp_err_t
gpio_pulldown_dis
(gpio_num_t gpio_num)¶ Disable pull-down on GPIO.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG Parameter error
- Parameters
gpio_num
: GPIO number
-
esp_err_t
gpio_install_isr_service
(int intr_alloc_flags)¶ Install the driver’s GPIO ISR handler service, which allows per-pin GPIO interrupt handlers.
This function is incompatible with gpio_isr_register() - if that function is used, a single global ISR is registered for all GPIO interrupts. If this function is used, the ISR service provides a global GPIO ISR and individual pin handlers are registered via the gpio_isr_handler_add() function.
- Return
- ESP_OK Success
- ESP_FAIL Operation fail
- ESP_ERR_NO_MEM No memory to install this service
- Parameters
intr_alloc_flags
: Flags used to allocate the interrupt. One or multiple (ORred) ESP_INTR_FLAG_* values. See esp_intr_alloc.h for more info.
-
void
gpio_uninstall_isr_service
()¶ Uninstall the driver’s GPIO ISR service, freeing related resources.
-
esp_err_t
gpio_isr_handler_add
(gpio_num_t gpio_num, gpio_isr_t isr_handler, void *args)¶ Add ISR handler for the corresponding GPIO pin.
Call this function after using gpio_install_isr_service() to install the driver’s GPIO ISR handler service.
The pin ISR handlers no longer need to be declared with IRAM_ATTR, unless you pass the ESP_INTR_FLAG_IRAM flag when allocating the ISR in gpio_install_isr_service().
This ISR handler will be called from an ISR. So there is a stack size limit (configurable as “ISR stack size” in menuconfig). This limit is smaller compared to a global GPIO interrupt handler due to the additional level of indirection.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_STATE Wrong state, the ISR service has not been initialized.
- ESP_ERR_INVALID_ARG Parameter error
- Parameters
gpio_num
: GPIO numberisr_handler
: ISR handler function for the corresponding GPIO number.args
: parameter for ISR handler.
-
esp_err_t
gpio_isr_handler_remove
(gpio_num_t gpio_num)¶ Remove ISR handler for the corresponding GPIO pin.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_STATE Wrong state, the ISR service has not been initialized.
- ESP_ERR_INVALID_ARG Parameter error
- Parameters
gpio_num
: GPIO number
-
esp_err_t
gpio_set_drive_capability
(gpio_num_t gpio_num, gpio_drive_cap_t strength)¶ Set GPIO pad drive capability.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG Parameter error
- Parameters
gpio_num
: GPIO number, only support output GPIOsstrength
: Drive capability of the pad
-
esp_err_t
gpio_get_drive_capability
(gpio_num_t gpio_num, gpio_drive_cap_t *strength)¶ Get GPIO pad drive capability.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG Parameter error
- Parameters
gpio_num
: GPIO number, only support output GPIOsstrength
: Pointer to accept drive capability of the pad
Structures¶
-
struct
gpio_config_t
¶ Configuration parameters of GPIO pad for gpio_config function.
Public Members
-
uint64_t
pin_bit_mask
¶ GPIO pin: set with bit mask, each bit maps to a GPIO
-
gpio_mode_t
mode
¶ GPIO mode: set input/output mode
-
gpio_pullup_t
pull_up_en
¶ GPIO pull-up
-
gpio_pulldown_t
pull_down_en
¶ GPIO pull-down
-
gpio_int_type_t
intr_type
¶ GPIO interrupt type
-
uint64_t
Macros¶
-
GPIO_SEL_0
¶ Pin 0 selected
-
GPIO_SEL_1
¶ Pin 1 selected
-
GPIO_SEL_2
¶ Pin 2 selected
- Note
- There are more macros like that up to pin 39, excluding pins 20, 24 and 28..31. They are not shown here to reduce redundant information.
-
GPIO_IS_VALID_GPIO
(gpio_num)¶ Check whether it is a valid GPIO number
-
GPIO_IS_VALID_OUTPUT_GPIO
(gpio_num)¶ Check whether it can be a valid GPIO number of output mode
Enumerations¶
-
enum
gpio_num_t
¶ Values:
-
GPIO_NUM_0
= 0¶ GPIO0, input and output
-
GPIO_NUM_1
= 1¶ GPIO1, input and output
-
GPIO_NUM_2
= 2¶ GPIO2, input and output
- Note
- There are more enumerations like that up to GPIO39, excluding GPIO20, GPIO24 and GPIO28..31. They are not shown here to reduce redundant information.
- Note
- GPIO34..39 are input mode only.
-
-
enum
gpio_int_type_t
¶ Values:
-
GPIO_INTR_DISABLE
= 0¶ Disable GPIO interrupt
-
GPIO_INTR_POSEDGE
= 1¶ GPIO interrupt type : rising edge
-
GPIO_INTR_NEGEDGE
= 2¶ GPIO interrupt type : falling edge
-
GPIO_INTR_ANYEDGE
= 3¶ GPIO interrupt type : both rising and falling edge
-
GPIO_INTR_LOW_LEVEL
= 4¶ GPIO interrupt type : input low level trigger
-
GPIO_INTR_HIGH_LEVEL
= 5¶ GPIO interrupt type : input high level trigger
-
GPIO_INTR_MAX
¶
-
-
enum
gpio_mode_t
¶ Values:
-
GPIO_MODE_DISABLE
= GPIO_MODE_DEF_DISABLE¶ GPIO mode : disable input and output
-
GPIO_MODE_INPUT
= GPIO_MODE_DEF_INPUT¶ GPIO mode : input only
-
GPIO_MODE_OUTPUT
= GPIO_MODE_DEF_OUTPUT¶ GPIO mode : output only mode
-
GPIO_MODE_OUTPUT_OD
= ((GPIO_MODE_DEF_OUTPUT)|(GPIO_MODE_DEF_OD))¶ GPIO mode : output only with open-drain mode
-
GPIO_MODE_INPUT_OUTPUT_OD
= ((GPIO_MODE_DEF_INPUT)|(GPIO_MODE_DEF_OUTPUT)|(GPIO_MODE_DEF_OD))¶ GPIO mode : output and input with open-drain mode
-
GPIO_MODE_INPUT_OUTPUT
= ((GPIO_MODE_DEF_INPUT)|(GPIO_MODE_DEF_OUTPUT))¶ GPIO mode : output and input mode
-
-
enum
gpio_pullup_t
¶ Values:
-
GPIO_PULLUP_DISABLE
= 0x0¶ Disable GPIO pull-up resistor
-
GPIO_PULLUP_ENABLE
= 0x1¶ Enable GPIO pull-up resistor
-
-
enum
gpio_pulldown_t
¶ Values:
-
GPIO_PULLDOWN_DISABLE
= 0x0¶ Disable GPIO pull-down resistor
-
GPIO_PULLDOWN_ENABLE
= 0x1¶ Enable GPIO pull-down resistor
-
-
enum
gpio_pull_mode_t
¶ Values:
-
GPIO_PULLUP_ONLY
¶ Pad pull up
-
GPIO_PULLDOWN_ONLY
¶ Pad pull down
-
GPIO_PULLUP_PULLDOWN
¶ Pad pull up + pull down
-
GPIO_FLOATING
¶ Pad floating
-
-
enum
gpio_drive_cap_t
¶ Values:
-
GPIO_DRIVE_CAP_0
= 0¶ Pad drive capability: weak
-
GPIO_DRIVE_CAP_1
= 1¶ Pad drive capability: stronger
-
GPIO_DRIVE_CAP_2
= 2¶ Pad drive capability: default value
-
GPIO_DRIVE_CAP_DEFAULT
= 2¶ Pad drive capability: default value
-
GPIO_DRIVE_CAP_3
= 3¶ Pad drive capability: strongest
-
GPIO_DRIVE_CAP_MAX
¶
-
API Reference - RTC GPIO¶
Header File¶
Functions¶
-
static bool
rtc_gpio_is_valid_gpio
(gpio_num_t gpio_num)¶ Determine if the specified GPIO is a valid RTC GPIO.
- Return
- true if GPIO is valid for RTC GPIO use. talse otherwise.
- Parameters
gpio_num
: GPIO number
-
esp_err_t
rtc_gpio_init
(gpio_num_t gpio_num)¶ Init a GPIO as RTC GPIO.
This function must be called when initializing a pad for an analog function.
- Return
- ESP_OK success
- ESP_ERR_INVALID_ARG GPIO is not an RTC IO
- Parameters
gpio_num
: GPIO number (e.g. GPIO_NUM_12)
-
esp_err_t
rtc_gpio_deinit
(gpio_num_t gpio_num)¶ Init a GPIO as digital GPIO.
- Return
- ESP_OK success
- ESP_ERR_INVALID_ARG GPIO is not an RTC IO
- Parameters
gpio_num
: GPIO number (e.g. GPIO_NUM_12)
-
uint32_t
rtc_gpio_get_level
(gpio_num_t gpio_num)¶ Get the RTC IO input level.
- Return
- 1 High level
- 0 Low level
- ESP_ERR_INVALID_ARG GPIO is not an RTC IO
- Parameters
gpio_num
: GPIO number (e.g. GPIO_NUM_12)
-
esp_err_t
rtc_gpio_set_level
(gpio_num_t gpio_num, uint32_t level)¶ Set the RTC IO output level.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG GPIO is not an RTC IO
- Parameters
gpio_num
: GPIO number (e.g. GPIO_NUM_12)level
: output level
-
esp_err_t
rtc_gpio_set_direction
(gpio_num_t gpio_num, rtc_gpio_mode_t mode)¶ RTC GPIO set direction.
Configure RTC GPIO direction, such as output only, input only, output and input.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG GPIO is not an RTC IO
- Parameters
gpio_num
: GPIO number (e.g. GPIO_NUM_12)mode
: GPIO direction
-
esp_err_t
rtc_gpio_pullup_en
(gpio_num_t gpio_num)¶ RTC GPIO pullup enable.
This function only works for RTC IOs. In general, call gpio_pullup_en, which will work both for normal GPIOs and RTC IOs.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG GPIO is not an RTC IO
- Parameters
gpio_num
: GPIO number (e.g. GPIO_NUM_12)
-
esp_err_t
rtc_gpio_pulldown_en
(gpio_num_t gpio_num)¶ RTC GPIO pulldown enable.
This function only works for RTC IOs. In general, call gpio_pulldown_en, which will work both for normal GPIOs and RTC IOs.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG GPIO is not an RTC IO
- Parameters
gpio_num
: GPIO number (e.g. GPIO_NUM_12)
-
esp_err_t
rtc_gpio_pullup_dis
(gpio_num_t gpio_num)¶ RTC GPIO pullup disable.
This function only works for RTC IOs. In general, call gpio_pullup_dis, which will work both for normal GPIOs and RTC IOs.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG GPIO is not an RTC IO
- Parameters
gpio_num
: GPIO number (e.g. GPIO_NUM_12)
-
esp_err_t
rtc_gpio_pulldown_dis
(gpio_num_t gpio_num)¶ RTC GPIO pulldown disable.
This function only works for RTC IOs. In general, call gpio_pulldown_dis, which will work both for normal GPIOs and RTC IOs.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG GPIO is not an RTC IO
- Parameters
gpio_num
: GPIO number (e.g. GPIO_NUM_12)
-
esp_err_t
rtc_gpio_hold_en
(gpio_num_t gpio_num)¶ Enable hold function on an RTC IO pad.
Enabling HOLD function will cause the pad to latch current values of input enable, output enable, output value, function, drive strength values. This function is useful when going into light or deep sleep mode to prevent the pin configuration from changing.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG GPIO is not an RTC IO
- Parameters
gpio_num
: GPIO number (e.g. GPIO_NUM_12)
-
esp_err_t
rtc_gpio_hold_dis
(gpio_num_t gpio_num)¶ Disable hold function on an RTC IO pad.
Disabling hold function will allow the pad receive the values of input enable, output enable, output value, function, drive strength from RTC_IO peripheral.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG GPIO is not an RTC IO
- Parameters
gpio_num
: GPIO number (e.g. GPIO_NUM_12)
-
void
rtc_gpio_force_hold_dis_all
()¶ Disable force hold signal for all RTC IOs.
Each RTC pad has a “force hold” input signal from the RTC controller. If this signal is set, pad latches current values of input enable, function, output enable, and other signals which come from the RTC mux. Force hold signal is enabled before going into deep sleep for pins which are used for EXT1 wakeup.
-
esp_err_t
rtc_gpio_set_drive_capability
(gpio_num_t gpio_num, gpio_drive_cap_t strength)¶ Set RTC GPIO pad drive capability.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG Parameter error
- Parameters
gpio_num
: GPIO number, only support output GPIOsstrength
: Drive capability of the pad
-
esp_err_t
rtc_gpio_get_drive_capability
(gpio_num_t gpio_num, gpio_drive_cap_t *strength)¶ Get RTC GPIO pad drive capability.
- Return
- ESP_OK Success
- ESP_ERR_INVALID_ARG Parameter error
- Parameters
gpio_num
: GPIO number, only support output GPIOsstrength
: Pointer to accept drive capability of the pad
Structures¶
-
struct
rtc_gpio_desc_t
¶ Pin function information for a single GPIO pad’s RTC functions.
This is an internal function of the driver, and is not usually useful for external use.
Public Members
-
uint32_t
reg
¶ Register of RTC pad, or 0 if not an RTC GPIO
-
uint32_t
mux
¶ Bit mask for selecting digital pad or RTC pad
-
uint32_t
func
¶ Shift of pad function (FUN_SEL) field
-
uint32_t
ie
¶ Mask of input enable
-
uint32_t
pullup
¶ Mask of pullup enable
-
uint32_t
pulldown
¶ Mask of pulldown enable
-
uint32_t
slpsel
¶ If slpsel bit is set, slpie will be used as pad input enabled signal in sleep mode
-
uint32_t
slpie
¶ Mask of input enable in sleep mode
-
uint32_t
hold
¶ Mask of hold enable
-
uint32_t
hold_force
¶ Mask of hold_force bit for RTC IO in RTC_CNTL_HOLD_FORCE_REG
-
uint32_t
drv_v
¶ Mask of drive capability
-
uint32_t
drv_s
¶ Offset of drive capability
-
int
rtc_num
¶ RTC IO number, or -1 if not an RTC GPIO
-
uint32_t