ir_mlx.c

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/*
 * Copyright (C) 2010 Martin Mueller
 *
 * This file is part of paparazzi.
 *
 * paparazzi is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * paparazzi is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with paparazzi; see the file COPYING.  If not, write to
 * the Free Software Foundation, 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 */
 
#include "modules/meteo/ir_mlx.h"
 
#include "mcu_periph/sys_time.h"
#include "mcu_periph/i2c.h"
#include "led.h"
#include "mcu_periph/uart.h"
#include "pprzlink/messages.h"
#include "modules/datalink/downlink.h"
 
 
#ifndef MLX_I2C_DEV
#define MLX_I2C_DEV i2c0
#endif
 
struct i2c_transaction mlx_trans;
 
uint8_t  ir_mlx_status;
uint16_t ir_mlx_itemp_case;
float    ir_mlx_temp_case;
uint16_t ir_mlx_itemp_obj;
float    ir_mlx_temp_obj;
uint32_t ir_mlx_id_01;
uint32_t ir_mlx_id_23;
 
/* I2C address is set to 6 (8 bit) */
#ifndef MLX90614_ADDR
#define MLX90614_ADDR 0x06
#endif
 
#define MLX90614_GENERAL_ADDR 0
 
//    printf("Ta    = %2.2f°C (0x%04X)\n", (tp*0.02)-273.15, tp);
 
void ir_mlx_crc(unsigned char addr, volatile unsigned char *data)
{
  unsigned char i, bit, crc = 0;
 
  for (i = 0; i < 4; i++) {
    if (i != 0) { crc ^= (data[i - 1]); }
    else { crc ^= addr; }
    for (bit = 8; bit > 0; bit--) {
      if (crc & 0x80)
        /* SMBus x^8 + x^2 + x + 1 */
      {
        crc = (crc << 1) ^ 0x107;
      } else {
        crc = (crc << 1);
      }
    }
  }
  data[3] = crc;
}
 
void ir_mlx_init(void)
{
#ifdef IR_MLX_ONE_TIME_CONFIG
#warning Starting MLX90614 in CONFIGURATION MODE, do this only once for
#warning setup, then turn this MODE off again and recompile/flash
  ir_mlx_status = IR_MLX_ADDR_CHANGE;
#else
  ir_mlx_status = IR_MLX_UNINIT;
#endif
}
 
void ir_mlx_periodic(void)
{
#ifdef IR_MLX_ONE_TIME_CONFIG
  if (sys_time.nb_sec > 4) {
#else
  if (sys_time.nb_sec > 1) {
#endif
    if (ir_mlx_status >= IR_MLX_IDLE) {
      /* start two byte case temperature */
      mlx_trans.buf[0] = MLX90614_TA;
      i2c_transceive(&MLX_I2C_DEV, &mlx_trans, MLX90614_ADDR, 1, 2);
      ir_mlx_status = IR_MLX_RD_CASE_TEMP;
      /* send serial number every 30 seconds */
      RunOnceEvery((8 * 30), DOWNLINK_SEND_MLX_SERIAL(DefaultChannel, DefaultDevice, &ir_mlx_id_01, &ir_mlx_id_23));
    } else if (ir_mlx_status == IR_MLX_UNINIT) {
      /* start two byte ID 0 */
      mlx_trans.buf[0] = MLX90614_ID_0;
      i2c_transceive(&MLX_I2C_DEV, &mlx_trans, MLX90614_ADDR, 1, 2);
      ir_mlx_status = IR_MLX_RD_ID_0;
    }
  }
#ifdef IR_MLX_ONE_TIME_CONFIG
  else if ((sys_time.nb_sec > 1) && (ir_mlx_status == IR_MLX_ADDR_CHANGE)) {
    /* erase address by writing zero to SMBus address register */
    ir_mlx_status = IR_MLX_ADDR_ERASE;
    mlx_trans.buf[0] = MLX90614_SADR;
    mlx_trans.buf[1] = 0;
    mlx_trans.buf[2] = 0;
    ir_mlx_crc(MLX90614_GENERAL_ADDR, mlx_trans.buf);
    i2c_transmit(&MLX_I2C_DEV, &mlx_trans, MLX90614_GENERAL_ADDR, 4);
  } else if ((sys_time.nb_sec > 2) && (ir_mlx_status == IR_MLX_ADDR_ERASE)) {
    /* set address by writing it to AMBus address register */
    ir_mlx_status = IR_MLX_ADDR_SET;
    mlx_trans.buf[0] = MLX90614_SADR;
    mlx_trans.buf[1] = MLX90614_ADDR >> 1;
    mlx_trans.buf[2] = 0;
    ir_mlx_crc(MLX90614_GENERAL_ADDR, mlx_trans.buf);
    i2c_transmit(&MLX_I2C_DEV, &mlx_trans, MLX90614_GENERAL_ADDR, 4);
  } else if ((sys_time.nb_sec > 3) && (ir_mlx_status == IR_MLX_ADDR_SET)) {
    ir_mlx_status = IR_MLX_UNINIT;
  }
#endif
}
 
void ir_mlx_event(void)
{
  if ((mlx_trans.status == I2CTransSuccess)) {
    switch (ir_mlx_status) {
 
      case IR_MLX_RD_ID_0:
        /* read two byte ID 0 */
        ir_mlx_id_01  = mlx_trans.buf[0];
        ir_mlx_id_01 |= mlx_trans.buf[1] << 8;
        /* start two byte ID 1 */
        mlx_trans.buf[0] = MLX90614_ID_1;
        i2c_transceive(&MLX_I2C_DEV, &mlx_trans, MLX90614_ADDR, 1, 2);
        ir_mlx_status = IR_MLX_RD_ID_1;
        break;
 
      case IR_MLX_RD_ID_1:
        /* read two byte ID 1 */
        ir_mlx_id_01 |= mlx_trans.buf[0] << 16;
        ir_mlx_id_01 |= mlx_trans.buf[1] << 24;
        /* start two byte ID 2 */
        mlx_trans.buf[0] = MLX90614_ID_2;
        i2c_transceive(&MLX_I2C_DEV, &mlx_trans, MLX90614_ADDR, 1, 2);
        ir_mlx_status = IR_MLX_RD_ID_2;
        break;
 
      case IR_MLX_RD_ID_2:
        /* read two byte ID 2 */
        ir_mlx_id_23  = mlx_trans.buf[0];
        ir_mlx_id_23 |= mlx_trans.buf[1] << 8;
        /* start two byte ID 3 */
        mlx_trans.buf[0] = MLX90614_ID_3;
        i2c_transceive(&MLX_I2C_DEV, &mlx_trans, MLX90614_ADDR, 1, 2);
        ir_mlx_status = IR_MLX_RD_ID_3;
        break;
 
      case IR_MLX_RD_ID_3:
        /* read two byte ID 3 */
        ir_mlx_id_23 |= mlx_trans.buf[0] << 16;
        ir_mlx_id_23 |= mlx_trans.buf[1] << 24;
        ir_mlx_status = IR_MLX_IDLE;
        mlx_trans.status = I2CTransDone;
        DOWNLINK_SEND_MLX_SERIAL(DefaultChannel, DefaultDevice, &ir_mlx_id_01, &ir_mlx_id_23);
        break;
 
      case IR_MLX_RD_CASE_TEMP:
        /* read two byte case temperature */
        ir_mlx_itemp_case  = mlx_trans.buf[1] << 8;
        ir_mlx_itemp_case |= mlx_trans.buf[0];
        ir_mlx_temp_case = ir_mlx_itemp_case * 0.02 - 273.15;
 
        /* start two byte obj temperature */
        mlx_trans.buf[0] = MLX90614_TOBJ;
        i2c_transceive(&MLX_I2C_DEV, &mlx_trans, MLX90614_ADDR, 1, 2);
        ir_mlx_status = IR_MLX_RD_OBJ_TEMP;
        break;
 
      case IR_MLX_RD_OBJ_TEMP:
        /* read two byte obj temperature */
        ir_mlx_itemp_obj  = mlx_trans.buf[1] << 8;
        ir_mlx_itemp_obj |= mlx_trans.buf[0];
        ir_mlx_temp_obj = ir_mlx_itemp_obj * 0.02 - 273.15;
        mlx_trans.status = I2CTransDone;
 
        DOWNLINK_SEND_MLX_STATUS(DefaultChannel, DefaultDevice,
                                 &ir_mlx_itemp_case,
                                 &ir_mlx_temp_case,
                                 &ir_mlx_itemp_obj,
                                 &ir_mlx_temp_obj);
        break;
      default:
        mlx_trans.status = I2CTransDone;
        break;
    }
  }
}