/*
* Driver for AMS CCS811 digital gas sensor connected to I2C.
*
* This driver is for the usage with the ESP8266 and FreeRTOS (esp-open-rtos)
* [https://github.com/SuperHouse/esp-open-rtos]. It is also working with ESP32
* and ESP-IDF [https://github.com/espressif/esp-idf.git] as well as Linux
* based systems using a wrapper library for ESP8266 functions.
*
* ---------------------------------------------------------------------------
*
* The BSD License (3-clause license)
*
* Copyright (c) 2017 Gunar Schorcht (https://github.com/gschorcht)
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <string.h>
#include <stdlib.h>
#include "ccs811.h"
#if defined(CCS811_DEBUG_LEVEL_2)
#define debug(s, f, ...) printf("%s %s: " s "\n", "CCS811", f, ## __VA_ARGS__)
#define debug_dev(s, f, d, ...) printf("%s %s: bus %d, addr %02x - " s "\n", "CCS811", f, d->bus, d->addr, ## __VA_ARGS__)
#else
#define debug(s, f, ...)
#define debug_dev(s, f, d, ...)
#endif
#if defined(CCS811_DEBUG_LEVEL_1) || defined(CCS811_DEBUG_LEVEL_2)
#define error(s, f, ...) printf("%s %s: " s "\n", "CCS811", f, ## __VA_ARGS__)
#define error_dev(s, f, d, ...) printf("%s %s: bus %d, addr %02x - " s "\n", "CCS811", f, d->bus, d->addr, ## __VA_ARGS__)
#else
#define error(s, f, ...)
#define error_dev(s, f, d, ...)
#endif
/* CCS811 register addresses */
#define CCS811_REG_STATUS 0x00
#define CCS811_REG_MEAS_MODE 0x01
#define CCS811_REG_ALG_RESULT_DATA 0x02
#define CCS811_REG_RAW_DATA 0x03
#define CCS811_REG_ENV_DATA 0x05
#define CCS811_REG_NTC 0x06
#define CCS811_REG_THRESHOLDS 0x10
#define CCS811_REG_BASELINE 0x11
#define CCS811_REG_HW_ID 0x20
#define CCS811_REG_HW_VER 0x21
#define CCS811_REG_FW_BOOT_VER 0x23
#define CCS811_REG_FW_APP_VER 0x24
#define CCS811_REG_ERROR_ID 0xe0
#define CCS811_REG_APP_ERASE 0xf1
#define CCS811_REG_APP_DATA 0xf2
#define CCS811_REG_APP_VERIFY 0xf3
#define CCS811_REG_APP_START 0xf4
#define CCS811_REG_SW_RESET 0xff
// status register bits
#define CCS811_STATUS_ERROR 0x01 // error, details in CCS811_REG_ERROR
#define CCS811_STATUS_DATA_RDY 0x08 // new data sample in ALG_RESULT_DATA
#define CCS811_STATUS_APP_VALID 0x10 // valid application firmware loaded
#define CCS811_STATUS_FW_MODE 0x80 // firmware is in application mode
// error register bits
#define CCS811_ERR_WRITE_REG_INV 0x01 // invalid register address on write
#define CCS811_ERR_READ_REG_INV 0x02 // invalid register address on read
#define CCS811_ERR_MEASMODE_INV 0x04 // invalid requested measurement mode
#define CCS811_ERR_MAX_RESISTANCE 0x08 // maximum sensor resistance exceeded
#define CCS811_ERR_HEATER_FAULT 0x10 // heater current not in range
#define CCS811_ERR_HEATER_SUPPLY 0x20 // heater voltage not applied correctly
/**
* Type declarations
*/
typedef struct
{
uint8_t reserved_1 :2;
uint8_t int_thresh :1; // interrupt if new ALG_RESULT_DAT crosses on of the thresholds
uint8_t int_datardy:1; // interrupt if new sample is ready in ALG_RESULT_DAT
uint8_t drive_mode :3; // mode number binary coded
} ccs811_meas_mode_reg_t;
/**
* forward declaration of functions for internal use only
*/
static bool ccs811_reg_read(ccs811_sensor_t* dev, uint8_t reg, uint8_t *data, uint32_t len);
static bool ccs811_reg_write(ccs811_sensor_t* dev, uint8_t reg, uint8_t *data, uint32_t len);
static bool ccs811_check_error_status (ccs811_sensor_t* dev);
static bool ccs811_enable_threshold (ccs811_sensor_t* dev, bool enabled);
static bool ccs811_is_available (ccs811_sensor_t* dev);
ccs811_sensor_t* ccs811_init_sensor (uint8_t bus, uint8_t addr)
{
ccs811_sensor_t* dev;
if ((dev = malloc (sizeof(ccs811_sensor_t))) == NULL)
return NULL;
// init sensor data structure
dev->bus = bus;
dev->addr = addr;
dev->mode = ccs811_mode_idle;
dev->error_code = CCS811_OK;
// check whether sensor is available including the check of the hardware
// id and the error state
if (!ccs811_is_available(dev))
{
error_dev("Sensor is not available.", __FUNCTION__, dev);
free (dev);
return NULL;
}
const static uint8_t sw_reset[4] = { 0x11, 0xe5, 0x72, 0x8a };
// doing a software reset first
if (!ccs811_reg_write(dev, CCS811_REG_SW_RESET, (uint8_t*)sw_reset, 4))
{
error_dev("Could not reset the sensor.", __FUNCTION__, dev);
free (dev);
return NULL;
}
uint8_t status;
// wait 100 ms after the reset
vTaskDelay(100/portTICK_PERIOD_MS);
// get the status to check whether sensor is in bootloader mode
if (!ccs811_reg_read(dev, CCS811_REG_STATUS, &status, 1))
{
error_dev("Could not read status register %02x.", __FUNCTION__, dev, CCS811_REG_STATUS);
free (dev);
return NULL;
}
// if sensor is in bootloader mode (FW_MODE == 0), it has to switch
// to the application mode first
if (!(status & CCS811_STATUS_FW_MODE))
{
// check whether valid application firmware is loaded
if (!(status & CCS811_STATUS_APP_VALID))
{
error_dev("Sensor is in boot mode, but has no valid application.",
__FUNCTION__, dev);
free (dev);
return NULL;
}
// swtich to application mode
if (!ccs811_reg_write(dev, CCS811_REG_APP_START, 0, 0))
{
error_dev("Could not start application", __FUNCTION__, dev);
free (dev);
return NULL;
}
// wait 100 ms after starting the app
vTaskDelay(100/portTICK_PERIOD_MS);
// get the status to check whether sensor switched to application mode
if (!ccs811_reg_read(dev, CCS811_REG_STATUS, &status, 1) ||
!(status & CCS811_STATUS_FW_MODE))
{
error_dev("Could not start application.", __FUNCTION__, dev);
free (dev);
return NULL;
}
}
// try to set default measurement mode to *ccs811_mode_1s*
if (!ccs811_set_mode(dev, ccs811_mode_1s))
{
free (dev);
return NULL;
}
return dev;
}
bool ccs811_set_mode (ccs811_sensor_t* dev, ccs811_mode_t mode)
{
ccs811_meas_mode_reg_t reg;
if (!dev) return false;
dev->error_code = CCS811_OK;
// read measurement mode register value
if (!ccs811_reg_read(dev, CCS811_REG_MEAS_MODE, (uint8_t*)®, 1))
return false;
reg.drive_mode = mode;
// write back measurement mode register
if (!ccs811_reg_write(dev, CCS811_REG_MEAS_MODE, (uint8_t*)®, 1))
{
error_dev ("Could not set measurement mode.", __FUNCTION__, dev);
return false;
}
// check whether setting measurement mode were succesfull
if (!ccs811_reg_read(dev, CCS811_REG_MEAS_MODE, (uint8_t*)®, 1) ||
reg.drive_mode != mode)
{
error_dev ("Could not set measurement mode to %d", __FUNCTION__, dev, mode);
return ccs811_check_error_status (dev);
}
dev->mode = mode;
return true;
}
#define CCS811_ALG_DATA_ECO2_HB 0
#define CCS811_ALG_DATA_ECO2_LB 1
#define CCS811_ALG_DATA_TVOC_HB 2
#define CCS811_ALG_DATA_TVOC_LB 3
#define CCS811_ALG_DATA_STATUS 4
#define CCS811_ALG_DATA_ERROR_ID 5
#define CCS811_ALG_DATA_RAW_HB 6
#define CCS811_ALG_DATA_RAW_LB 7
bool ccs811_get_results (ccs811_sensor_t* dev,
uint16_t* iaq_tvoc,
uint16_t* iaq_eco2,
uint8_t* raw_i,
uint16_t* raw_v)
{
if (!dev) return false;
dev->error_code = CCS811_OK;
if (dev->mode == ccs811_mode_idle)
{
error_dev ("Sensor is in idle mode and not performing measurements.",
__FUNCTION__, dev);
dev->error_code = CCS811_DRV_WRONG_MODE;
return false;
}
if (dev->mode == ccs811_mode_250ms && (iaq_tvoc || iaq_eco2))
{
error_dev ("Sensor is in constant power mode, only raw data "
"are available every 250ms",
__FUNCTION__, dev);
dev->error_code = CCS811_DRV_NO_IAQ_DATA;
return false;
}
uint8_t data[8];
// read IAQ sensor values and RAW sensor data including status and error id
if (!ccs811_reg_read(dev, CCS811_REG_ALG_RESULT_DATA, data, 8))
{
error_dev ("Could not read sensor data.", __FUNCTION__, dev);
dev->error_code |= CCS811_DRV_RD_DATA_FAILED;
return false;
}
// check for errors
if (data[CCS811_ALG_DATA_STATUS] & CCS811_STATUS_ERROR)
{
return ccs811_check_error_status (dev);
}
// check whether new data are ready, if not, latest values are read from sensor
// and error_code is set
if (!(data[CCS811_ALG_DATA_STATUS] & CCS811_STATUS_DATA_RDY))
{
debug_dev ("No new data.", __FUNCTION__, dev);
dev->error_code = CCS811_DRV_NO_NEW_DATA;
}
// if *iaq* is not NULL return IAQ sensor values
if (iaq_tvoc) *iaq_tvoc = data[CCS811_ALG_DATA_TVOC_HB] << 8 | data[CCS811_ALG_DATA_TVOC_LB];
if (iaq_eco2) *iaq_eco2 = data[CCS811_ALG_DATA_ECO2_HB] << 8 | data[CCS811_ALG_DATA_ECO2_LB];
// if *raw* is not NULL return RAW sensor data
if (raw_i) *raw_i = data[CCS811_ALG_DATA_RAW_HB] >> 2;
if (raw_v) *raw_v = (data[CCS811_ALG_DATA_RAW_HB] & 0x03) << 8 | data[CCS811_ALG_DATA_RAW_LB];
return true;
}
uint32_t ccs811_get_ntc_resistance (ccs811_sensor_t* dev, uint32_t r_ref)
{
if (!dev) return 0;
uint8_t data[4];
// read baseline register
if (!ccs811_reg_read(dev, CCS811_REG_NTC, data, 4))
return 0;
// calculation from application note ams AN000372
uint16_t v_ref = (uint16_t)(data[0]) << 8 | data[1];
uint16_t v_ntc = (uint16_t)(data[2]) << 8 | data[3];
return (v_ntc * r_ref / v_ref);
}
bool ccs811_set_environmental_data (ccs811_sensor_t* dev,
float temperature,
float humidity)
{
if (!dev) return false;
uint16_t temp = (temperature + 25) * 512; // -25 °C maps to 0
uint16_t hum = humidity * 512;
// fill environmental data
uint8_t data[4] = { temp >> 8, temp & 0xff,
hum >> 8, hum & 0xff };
// send environmental data to the sensor
if (!ccs811_reg_write(dev, CCS811_REG_ENV_DATA, data, 4))
{
error_dev ("Could not write environmental data to sensor.", __FUNCTION__, dev);
return false;
}
return true;
}
bool ccs811_set_eco2_thresholds (ccs811_sensor_t* dev,
uint16_t low, uint16_t high, uint8_t hysteresis)
{
if (!dev) return false;
dev->error_code = CCS811_OK;
// check whether interrupt has to be disabled
if (!low && !high && !hysteresis)
return ccs811_enable_threshold (dev, false);
// check parameters
if (low < CCS_ECO2_RANGE_MIN || high > CCS_ECO2_RANGE_MAX || low > high || !hysteresis)
{
error_dev ("Wrong threshold parameters", __FUNCTION__, dev);
dev->error_code = CCS811_DRV_WRONG_PARAMS;
return ccs811_enable_threshold (dev, false);
}
// fill the threshold data
uint8_t data[5] = { low >> 8, low & 0xff,
high >> 8, high & 0xff,
hysteresis };
// write threshold data to the sensor
if (!ccs811_reg_write(dev, CCS811_REG_THRESHOLDS, data, 5))
{
error_dev ("Could not write threshold interrupt data to sensor.", __FUNCTION__, dev);
return ccs811_enable_threshold (dev, false);
}
// finally enable the threshold interrupt mode
return ccs811_enable_threshold (dev, true);
}
bool ccs811_enable_interrupt (ccs811_sensor_t* dev, bool enabled)
{
if (!dev) return false;
ccs811_meas_mode_reg_t reg;
// read measurement mode register value
if (!ccs811_reg_read(dev, CCS811_REG_MEAS_MODE, (uint8_t*)®, 1))
return false;
reg.int_datardy = enabled;
reg.int_thresh = false; // threshold mode must not enabled
// write back measurement mode register
if (!ccs811_reg_write(dev, CCS811_REG_MEAS_MODE, (uint8_t*)®, 1))
{
error_dev ("Could not set measurment mode register.", __FUNCTION__, dev);
return false;
}
return true;
}
uint16_t ccs811_get_baseline (ccs811_sensor_t* dev)
{
if (!dev) return 0;
uint8_t data[2];
// read baseline register
if (!ccs811_reg_read(dev, CCS811_REG_BASELINE, data, 2))
return 0;
return (uint16_t)(data[0]) << 8 | data[1];
}
bool ccs811_set_baseline (ccs811_sensor_t* dev, uint16_t baseline)
{
if (!dev) return false;
uint8_t data[2] = { baseline >> 8, baseline & 0xff };
// write baseline register
if (!ccs811_reg_write(dev, CCS811_REG_BASELINE, data, 2))
return false;
return true;
}
/**
* FUNCTIONS FOR INTERNAL USE ONLY
*/
static bool ccs811_enable_threshold (ccs811_sensor_t* dev, bool enabled)
{
if (!dev) return false;
ccs811_meas_mode_reg_t reg;
// first, enable/disable the data ready interrupt
if (!ccs811_enable_interrupt (dev, enabled))
return false;
// read measurement mode register value
if (!ccs811_reg_read(dev, CCS811_REG_MEAS_MODE, (uint8_t*)®, 1))
return false;
// second, enable/disable the threshold interrupt mode
reg.int_thresh = enabled;
// write back measurement mode register
if (!ccs811_reg_write(dev, CCS811_REG_MEAS_MODE, (uint8_t*)®, 1))
{
error_dev ("Could not set measurement mode register.", __FUNCTION__, dev);
return false;
}
return true;
}
static bool ccs811_reg_read(ccs811_sensor_t* dev, uint8_t reg, uint8_t *data, uint32_t len)
{
if (!dev || !data) return false;
debug_dev ("Read %d byte from i2c slave starting at reg addr %02x.", __FUNCTION__, dev, len, reg);
int result = i2c_slave_read(dev->bus, dev->addr, ®, data, len);
if (result)
{
dev->error_code |= (result == -EBUSY) ? CCS811_I2C_BUSY : CCS811_I2C_READ_FAILED;
error_dev ("Error %d on read %d byte from I2C slave reg addr %02x.",
__FUNCTION__, dev, result, len, reg);
return false;
}
# ifdef CCS811_DEBUG_LEVEL_2
printf("CCS811 %s: bus %d, addr %02x - Read following bytes: ",
__FUNCTION__, dev->bus, dev->addr);
printf("%0x: ", reg);
for (int i=0; i < len; i++)
printf("%0x ", data[i]);
printf("\n");
# endif
return true;
}
static bool ccs811_reg_write(ccs811_sensor_t* dev, uint8_t reg, uint8_t *data, uint32_t len)
{
if (!dev) return false;
debug_dev ("Write %d bytes to i2c slave starting at reg addr %02x", __FUNCTION__, dev, len, reg);
# ifdef CCS811_DEBUG_LEVEL_2
if (data && len)
{
printf("CCS811 %s: bus %d, addr %02x - Write following bytes: ",
__FUNCTION__, dev->bus, dev->addr);
for (int i=0; i < len; i++)
printf("%02x ", data[i]);
printf("\n");
}
# endif
int result = i2c_slave_write(dev->bus, dev->addr, ®, data, len);
if (result)
{
dev->error_code |= (result == -EBUSY) ? CCS811_I2C_BUSY : CCS811_I2C_WRITE_FAILED;
error_dev ("Error %d on write %d byte to i2c slave register %02x.",
__FUNCTION__, dev, result, len, reg);
return false;
}
return true;
}
static bool ccs811_check_error_status (ccs811_sensor_t* dev)
{
if (!dev) return false;
dev->error_code = CCS811_OK;
uint8_t status;
uint8_t err_reg;
// check status register
if (!ccs811_reg_read(dev, CCS811_REG_STATUS, &status, 1))
return false;
if (!status & CCS811_STATUS_ERROR)
// everything is fine
return true;
// Check the error register
if (!ccs811_reg_read(dev, CCS811_REG_ERROR_ID, &err_reg, 1))
return false;
if (err_reg & CCS811_ERR_WRITE_REG_INV)
{
error_dev ("Received an invalid register for write.", __FUNCTION__, dev);
dev->error_code = CCS811_DRV_WR_REG_INV;
return false;
}
if (err_reg & CCS811_ERR_READ_REG_INV)
{
error_dev ("Received an invalid register for read.", __FUNCTION__, dev);
dev->error_code = CCS811_DRV_RD_REG_INV;
return false;
}
if (err_reg & CCS811_ERR_MEASMODE_INV)
{
error_dev ("Received an invalid measurement mode request.", __FUNCTION__, dev);
dev->error_code = CCS811_DRV_MM_INV;
return false;
}
if (err_reg & CCS811_ERR_MAX_RESISTANCE)
{
error_dev ("Sensor resistance measurement has reached"
" or exceeded the maximum range.", __FUNCTION__, dev);
dev->error_code = CCS811_DRV_MAX_RESIST;
return false;
}
if (err_reg & CCS811_ERR_HEATER_FAULT)
{
error_dev ("Heater current not in range.", __FUNCTION__, dev);
dev->error_code = CCS811_DRV_HEAT_FAULT;
return false;
}
if (err_reg & CCS811_ERR_HEATER_SUPPLY)
{
error_dev ("Heater voltage is not being applied correctly.", __FUNCTION__, dev);
dev->error_code = CCS811_DRV_HEAT_SUPPLY;
return false;
}
return true;
}
static bool ccs811_is_available (ccs811_sensor_t* dev)
{
if (!dev) return false;
uint8_t reg_data[5];
// check hardware id (register 0x20) and hardware version (register 0x21)
if (!ccs811_reg_read(dev, CCS811_REG_HW_ID, reg_data, 5))
return false;
if (reg_data[0] != 0x81)
{
error_dev ("Wrong hardware ID %02x, should be 0x81", __FUNCTION__, dev, reg_data[0]);
dev->error_code = CCS811_DRV_HW_ID;
return false;
}
debug_dev ("hardware version: %02x", __FUNCTION__, dev, reg_data[1]);
debug_dev ("firmware boot version: %02x", __FUNCTION__, dev, reg_data[3]);
debug_dev ("firmware app version: %02x", __FUNCTION__, dev, reg_data[4]);
return ccs811_check_error_status (dev);
}