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I2C ​

I2C API.

Functions for the Inter-IC-Communication Bus

Sysprops ​

syspropdescription
gpio_sdaSDA GPIO
gpio_sclSCL GPIO

Functions Overview ​

Name
CW_DRIVER_FUNCi2c_read(int hDev, uint8_t addr, uint8_t * data, uint8_t len)
CW_DRIVER_FUNCi2c_read_reg(int hDev, uint8_t addr, uint8_t reg, uint8_t * data, uint8_t len)
CW_DRIVER_FUNCi2c_write(int hDev, uint8_t addr, const uint8_t * data, uint8_t len)
CW_DRIVER_FUNCi2c_write_reg(int hDev, uint8_t addr, uint8_t reg, const uint8_t * data, uint8_t len)
CW_DRIVER_FUNCi2c_transfer(int hDev, uint8_t addr, const uint8_t * data_w, uint8_t len_w, uint8_t * data_r, uint8_t len_r)
CW_DRIVER_FUNCi2c_clear(int hDev)
resets a stuck bus by sending 9 clock pulses

Function Details ​

function i2c_read ​

cpp
CW_DRIVER_FUNC i2c_read(
    int hDev,
    uint8_t addr,
    uint8_t * data,
    uint8_t len
)

Parameters:

  • hDev device handle as returned by open(const char*)
  • addr the 7bit address of the device to read from.
  • data buffer holding the space for the data to be read.
  • len length of the data buffer in bytes.

Return: 0 if the data has successfully been read.

function i2c_read_reg ​

cpp
CW_DRIVER_FUNC i2c_read_reg(
    int hDev,
    uint8_t addr,
    uint8_t reg,
    uint8_t * data,
    uint8_t len
)

Parameters:

  • hDev device handle as returned by open(const char*)
  • addr the 7bit address of the device to read from.
  • reg the device register to read data from
  • data buffer holding the space for the data to be read.
  • len length of the data buffer in bytes.

Return: 0 if the data has successfully been read.

function i2c_write ​

cpp
CW_DRIVER_FUNC i2c_write(
    int hDev,
    uint8_t addr,
    const uint8_t * data,
    uint8_t len
)

Parameters:

  • hDev device handle as returned by open(const char*)
  • addr the 7bit address of the device to write to.
  • data buffer containing the data to be written.
  • len length of the data buffer in bytes.
  • send_stop pass 1 to send a STOP condition after completing the write, for a repeated-start pass 0.

Return: 0 if the data has been successfully written.

function i2c_write_reg ​

cpp
CW_DRIVER_FUNC i2c_write_reg(
    int hDev,
    uint8_t addr,
    uint8_t reg,
    const uint8_t * data,
    uint8_t len
)

Parameters:

  • hDev device handle as returned by open(const char*)
  • addr the 7bit address of the device to write to.
  • reg the device register to be written to
  • data buffer containing the data to be written.
  • len length of the data buffer in bytes.

Return: 0 if the data has been successfully written.

function i2c_transfer ​

cpp
CW_DRIVER_FUNC i2c_transfer(
    int hDev,
    uint8_t addr,
    const uint8_t * data_w,
    uint8_t len_w,
    uint8_t * data_r,
    uint8_t len_r
)

Parameters:

  • hDev device handle as returned by open(const char*)
  • addr the 7bit address of the device to write to.
  • data buffer containing the data to be written.
  • len length of the data buffer in bytes.
  • send_stop pass 1 to send a STOP condition after completing the write, for a repeated-start pass 0.

Return: 0 if the data has been successfully written.

function i2c_clear ​

cpp
CW_DRIVER_FUNC i2c_clear(
    int hDev
)

resets a stuck bus by sending 9 clock pulses

Parameters: