/* first send the master write cmd to slave */
master_write_req = MASTER_WRITE_CMD;

hal_i2c_master_tx(&i2c_handle,SLAVE_ADDRESS_WRITE,(uint8_t*)&master_write_req,1);
while(i2c_handle.State != HAL_I2C_STATE_READY);

master_write_req = WRITE_LEN;
/* Now send the number of bytes to be written */
hal_i2c_master_tx(&i2c_handle,SLAVE_ADDRESS_WRITE,(uint8_t*)&master_write_req,1);

while(i2c_handle.State != HAL_I2C_STATE_READY);

/* NOW send the data stream */
hal_i2c_master_tx(&i2c_handle,SLAVE_ADDRESS_WRITE,master_tx_buffer,WRITE_LEN);

while(i2c_handle.State != HAL_I2C_STATE_READY);