I2C/TWI with AVR Data Transfer

We now take a look at the TWI/I2C API responsible for data transfer. The header file twi.h has the prototype. We'll take a look at the arguments and their description now:

TWI_RET_E twi_send_recv_buffer(TWI_SEND_RECV_BUFFER_PARAMS_X *px_send_buffer_params,
                               TWI_MODE_E e_mode);

The first argument is a pointer to TWI_SEND_RECV_BUFFER_PARAMS_X defined as follows:

typedef struct _TWI_SEND_RECV_BUFFER_PARAMS_X
{
   uint8_t uc_dev_addr;
   uint8_t uc_dev_id;
   uint8_t *puc_reg_addr;
   uint32_t ui_reg_addr_sz;
   uint8_t *puc_data;
   uint32_t ui_data_sz;
    
}TWI_SEND_RECV_BUFFER_PARAMS_X;

Where

1. uc_dev_addr is the higher nibble of the I2C slave device address
2. uc_dev_id is the lower nibble of the I2C slave device address. It is used where the slave address can be configured
3. puc_reg_addr is the pointer to the buffer holding the register address of the slave device.
4. ui_reg_addr_sz is the size of the buffer with the register address.
5. puc_data is the pointer to the data buffer
6. ui_data_sz is the size of the data buffer.

The second argument is an enumeration which indicates if a send or receive operation is to be done

typedef enum _TWI_STATE_MODE_E
{
   eTWI_MODE_READ = 0,
   eTWI_MODE_WRITE,
   eTWI_MODE_INVALID

}TWI_MODE_E;