I2C¶

概述¶

ESP32 has two I2C controllers which can be set as master mode or slave mode.

应用程序示例¶

I2C master and slave example: peripherals/i2c.

API 参考手册¶

头文件¶

driver/include/driver/i2c.h

宏¶

I2C_APB_CLK_FREQ¶: I2C source clock is APB clock, 80MHz

I2C_FIFO_LEN¶: I2C hardware fifo length

类型定义¶

typedef void *i2c_cmd_handle_t¶: I2C command handle

枚举¶

enum i2c_mode_t¶

Values:

I2C_MODE_SLAVE = 0¶: I2C slave mode

I2C_MODE_MASTER¶: I2C master mode

I2C_MODE_MAX¶

enum i2c_rw_t¶

Values:

I2C_MASTER_WRITE = 0¶: I2C write data

I2C_MASTER_READ¶: I2C read data

enum i2c_trans_mode_t¶

Values:

I2C_DATA_MODE_MSB_FIRST = 0¶: I2C data msb first

I2C_DATA_MODE_LSB_FIRST = 1¶: I2C data lsb first

I2C_DATA_MODE_MAX¶

enum i2c_opmode_t¶

Values:

I2C_CMD_RESTART = 0¶: I2C restart command

I2C_CMD_WRITE¶: I2C write command

I2C_CMD_READ¶: I2C read command

I2C_CMD_STOP¶: I2C stop command

I2C_CMD_END¶: I2C end command

enum i2c_port_t¶

Values:

I2C_NUM_0 = 0¶: I2C port 0

I2C_NUM_1¶: I2C port 1

I2C_NUM_MAX¶

enum i2c_addr_mode_t¶

Values:

I2C_ADDR_BIT_7 = 0¶: I2C 7bit address for slave mode

I2C_ADDR_BIT_10¶: I2C 10bit address for slave mode

I2C_ADDR_BIT_MAX¶

结构体¶

struct i2c_config_t¶

I2C initialization parameters.

Public Members

i2c_mode_t mode¶: I2C mode

gpio_num_t sda_io_num¶: GPIO number for I2C sda signal

gpio_pullup_t sda_pullup_en¶: Internal GPIO pull mode for I2C sda signal

gpio_num_t scl_io_num¶: GPIO number for I2C scl signal

gpio_pullup_t scl_pullup_en¶: Internal GPIO pull mode for I2C scl signal

uint32_t clk_speed¶: I2C clock frequency for master mode, (no higher than 1MHz for now)

uint8_t addr_10bit_en¶: I2C 10bit address mode enable for slave mode

uint16_t slave_addr¶: I2C address for slave mode

函数¶

esp_err_t i2c_driver_install(i2c_port_t i2c_num, i2c_mode_t mode, size_t slv_rx_buf_len, size_t slv_tx_buf_len, int intr_alloc_flags)¶

I2C driver install.

Note

Only slave mode will use this value, driver will ignore this value in master mode.

Note

Only slave mode will use this value, driver will ignore this value in master mode.

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error
ESP_FAIL Driver install error

Parameters

i2c_num: I2C port number
mode: I2C mode( master or slave )
slv_rx_buf_len: receiving buffer size for slave mode

Parameters

slv_tx_buf_len: sending buffer size for slave mode

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.

esp_err_t i2c_driver_delete(i2c_port_t i2c_num)¶

I2C driver delete.

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

i2c_num: I2C port number

esp_err_t i2c_param_config(i2c_port_t i2c_num, const i2c_config_t *i2c_conf)¶

I2C parameter initialization.

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

i2c_num: I2C port number
i2c_conf: pointer to I2C parameter settings

esp_err_t i2c_reset_tx_fifo(i2c_port_t i2c_num)¶

reset I2C tx hardware fifo

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

i2c_num: I2C port number

esp_err_t i2c_reset_rx_fifo(i2c_port_t i2c_num)¶

reset I2C rx fifo

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

i2c_num: I2C port number

esp_err_t i2c_isr_register(i2c_port_t i2c_num, void (*fn)(void *), void *arg, int intr_alloc_flags, intr_handle_t *handle, )¶

I2C isr handler register.

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

i2c_num: I2C port number
fn: isr handler function
arg: parameter for isr 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.
handle: handle return from esp_intr_alloc.

esp_err_t i2c_isr_free(intr_handle_t handle)¶

to delete and free I2C isr.

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

handle: handle of isr.

esp_err_t i2c_set_pin(i2c_port_t i2c_num, gpio_num_t sda_io_num, gpio_num_t scl_io_num, gpio_pullup_t sda_pullup_en, gpio_pullup_t scl_pullup_en, i2c_mode_t mode)¶

Configure GPIO signal for I2C sck and sda.

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

i2c_num: I2C port number
sda_io_num: GPIO number for I2C sda signal
scl_io_num: GPIO number for I2C scl signal
sda_pullup_en: Whether to enable the internal pullup for sda pin
scl_pullup_en: Whether to enable the internal pullup for scl pin
mode: I2C mode

esp_err_t i2c_master_start(i2c_cmd_handle_t cmd_handle)¶

Queue command for I2C master to generate a start signal.

Note

Only call this function in I2C master mode Call i2c_master_cmd_begin() to send all queued commands

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

cmd_handle: I2C cmd link

esp_err_t i2c_master_write_byte(i2c_cmd_handle_t cmd_handle, uint8_t data, bool ack_en)¶

Queue command for I2C master to write one byte to I2C bus.

Note

Only call this function in I2C master mode Call i2c_master_cmd_begin() to send all queued commands

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

cmd_handle: I2C cmd link
data: I2C one byte command to write to bus
ack_en: enable ack check for master

esp_err_t i2c_master_write(i2c_cmd_handle_t cmd_handle, uint8_t *data, size_t data_len, bool ack_en)¶

Queue command for I2C master to write buffer to I2C bus.

Note

Only call this function in I2C master mode Call i2c_master_cmd_begin() to send all queued commands

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

cmd_handle: I2C cmd link
data: data to send
data_len: data length
ack_en: enable ack check for master

esp_err_t i2c_master_read_byte(i2c_cmd_handle_t cmd_handle, uint8_t *data, int ack)¶

Queue command for I2C master to read one byte from I2C bus.

Note

Only call this function in I2C master mode Call i2c_master_cmd_begin() to send all queued commands

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

cmd_handle: I2C cmd link
data: pointer accept the data byte
ack: ack value for read command

esp_err_t i2c_master_read(i2c_cmd_handle_t cmd_handle, uint8_t *data, size_t data_len, int ack)¶

Queue command for I2C master to read data from I2C bus.

Note

Only call this function in I2C master mode Call i2c_master_cmd_begin() to send all queued commands

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

cmd_handle: I2C cmd link
data: data buffer to accept the data from bus
data_len: read data length
ack: ack value for read command

esp_err_t i2c_master_stop(i2c_cmd_handle_t cmd_handle)¶

Queue command for I2C master to generate a stop signal.

Note

Only call this function in I2C master mode Call i2c_master_cmd_begin() to send all queued commands

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

cmd_handle: I2C cmd link

esp_err_t i2c_master_cmd_begin(i2c_port_t i2c_num, i2c_cmd_handle_t cmd_handle, portBASE_TYPE ticks_to_wait)¶

I2C master send queued commands. This function will trigger sending all queued commands. The task will be blocked until all the commands have been sent out. The I2C APIs are not thread-safe, if you want to use one I2C port in different tasks, you need to take care of the multi-thread issue.

Note

Only call this function in I2C master mode

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error
ESP_FAIL Sending command error, slave doesn’t ACK the transfer.
ESP_ERR_INVALID_STATE I2C driver not installed or not in master mode.
ESP_ERR_TIMEOUT Operation timeout because the bus is busy.

Parameters

i2c_num: I2C port number
cmd_handle: I2C command handler
ticks_to_wait: maximum wait ticks.

int i2c_slave_write_buffer(i2c_port_t i2c_num, uint8_t *data, int size, portBASE_TYPE ticks_to_wait)¶

I2C slave write data to internal ringbuffer, when tx fifo empty, isr will fill the hardware fifo from the internal ringbuffer.

Note

Only call this function in I2C slave mode

Return

ESP_FAIL(-1) Parameter error
Others(>=0) The number of data bytes that pushed to the I2C slave buffer.

Parameters

i2c_num: I2C port number
data: data pointer to write into internal buffer
size: data size
ticks_to_wait: Maximum waiting ticks

警告

doxygenfunction: Cannot find function “i2c_slave_read” in doxygen xml output for project “esp32-idf” from directory: xml/

esp_err_t i2c_set_period(i2c_port_t i2c_num, int high_period, int low_period)¶

set I2C master clock period

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

i2c_num: I2C port number
high_period: clock cycle number during SCL is high level, high_period is a 14 bit value
low_period: clock cycle number during SCL is low level, low_period is a 14 bit value

esp_err_t i2c_get_period(i2c_port_t i2c_num, int *high_period, int *low_period)¶

get I2C master clock period

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

i2c_num: I2C port number
high_period: pointer to get clock cycle number during SCL is high level, will get a 14 bit value
low_period: pointer to get clock cycle number during SCL is low level, will get a 14 bit value

esp_err_t i2c_set_start_timing(i2c_port_t i2c_num, int setup_time, int hold_time)¶

set I2C master start signal timing

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

i2c_num: I2C port number
setup_time: clock number between the falling-edge of SDA and rising-edge of SCL for start mark, it’s a 10-bit value.
hold_time: clock num between the falling-edge of SDA and falling-edge of SCL for start mark, it’s a 10-bit value.

esp_err_t i2c_get_start_timing(i2c_port_t i2c_num, int *setup_time, int *hold_time)¶

get I2C master start signal timing

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

i2c_num: I2C port number
setup_time: pointer to get setup time
hold_time: pointer to get hold time

esp_err_t i2c_set_stop_timing(i2c_port_t i2c_num, int setup_time, int hold_time)¶

set I2C master stop signal timing

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

i2c_num: I2C port number
setup_time: clock num between the rising-edge of SCL and the rising-edge of SDA, it’s a 10-bit value.
hold_time: clock number after the STOP bit’s rising-edge, it’s a 14-bit value.

esp_err_t i2c_get_stop_timing(i2c_port_t i2c_num, int *setup_time, int *hold_time)¶

get I2C master stop signal timing

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

i2c_num: I2C port number
setup_time: pointer to get setup time.
hold_time: pointer to get hold time.

esp_err_t i2c_set_data_timing(i2c_port_t i2c_num, int sample_time, int hold_time)¶

set I2C data signal timing

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

i2c_num: I2C port number
sample_time: clock number I2C used to sample data on SDA after the rising-edge of SCL, it’s a 10-bit value
hold_time: clock number I2C used to hold the data after the falling-edge of SCL, it’s a 10-bit value

esp_err_t i2c_get_data_timing(i2c_port_t i2c_num, int *sample_time, int *hold_time)¶

get I2C data signal timing

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

i2c_num: I2C port number
sample_time: pointer to get sample time
hold_time: pointer to get hold time

esp_err_t i2c_set_data_mode(i2c_port_t i2c_num, i2c_trans_mode_t tx_trans_mode, i2c_trans_mode_t rx_trans_mode)¶

set I2C data transfer mode

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

i2c_num: I2C port number
tx_trans_mode: I2C sending data mode
rx_trans_mode: I2C receving data mode

esp_err_t i2c_get_data_mode(i2c_port_t i2c_num, i2c_trans_mode_t *tx_trans_mode, i2c_trans_mode_t *rx_trans_mode)¶

get I2C data transfer mode

Return

ESP_OK Success
ESP_ERR_INVALID_ARG Parameter error

Parameters

i2c_num: I2C port number
tx_trans_mode: pointer to get I2C sending data mode
rx_trans_mode: pointer to get I2C receiving data mode

i2c_cmd_handle_t i2c_cmd_link_create()¶

Create and init I2C command link.

Note: Before we build I2C command link, we need to call i2c_cmd_link_create() to create a command link. After we finish sending the commands, we need to call i2c_cmd_link_delete() to release and return the resources.
Return: i2c command link handler

void i2c_cmd_link_delete(i2c_cmd_handle_t cmd_handle)¶

Free I2C command link.

Note

Before we build I2C command link, we need to call i2c_cmd_link_create() to create a command link. After we finish sending the commands, we need to call i2c_cmd_link_delete() to release and return the resources.

Parameters

cmd_handle: I2C command handle