/* * 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 #include #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); }