i2c_master_write_read_device() function

Perform a write followed by a read to a device on the I2C bus. A repeated start signal is used between the `write` and `read`, thus, the bus is not released until the two transactions are finished. This function is a wrapper to `i2c_master_start()`, `i2c_master_write()`, `i2c_master_read()`, etc... It shall only be called in I2C master mode.

Syntax

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Summary

Declaration

Definition

from i2c.h:240

esp_err_t i2c_master_write_read_device(i2c_port_t i2c_num, uint8_t device_address, const uint8_t* write_buffer, size_t write_size, uint8_t* read_buffer, size_t read_size, TickType_t ticks_to_wait);

Implemented in i2c.c:1093

Arguments

Argument

Description

i2c_num

I2C port number to perform the transfer on

device_address

I2C device's 7-bit address

write_buffer

Bytes to send on the bus

write_size

Size, in bytes, of the write buffer

read_buffer

Buffer to store the bytes received on the bus

read_size

Size, in bytes, of the read buffer

ticks_to_wait

Maximum ticks to wait before issuing a timeout.

Return value

- ESP_OK Success - ESP_ERR_INVALID_ARG Parameter error - ESP_FAIL Sending command error, slave hasn'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.