Reference
Library
Download and install the MCP9808 Library and Sample Program. (About how to install the library?)
API Description
/**
* @fn sleepMode
* @brief Sensor sleep mode, lower power consumption, failed to get sensor temp at this time
* @return bool type, indicate the returned status
* @retval true is set successfully
* @retval false is register lock is not allowed to be modified
*/
bool sleepMode(void);
/**
* @fn wakeUpMode
* @brief Sensor waking up mode, sensor data can be obtained normally at this time
* @return bool type, indicate the returned status
* @retval true is set successfully
* @retval false is register lock is not allowed to be modified
*/
bool wakeUpMode(void);
/**
* @fn wakeUpMode
* @brief Get the configured power mode
* @return bool type, indicate the returned status
* @retval true is waking up mode
* @retval false is sleep mode
*/
bool getPowerMode(void);
/**
* @fn setResolution
* @brief Set resolution of the temperature sensor, the accuracy of the acquired temp is different in different resolution
* @param resolution
* @n RESOLUTION_0_5 // The decimal part of the obtained temp is a multiple of 0.5 e.g. 0.5°C, 1.0°C, 1.5°C
* @n RESOLUTION_0_25 // The decimal part of the obtained temp is a multiple of 0.25 e.g. 0.25°C, 0.50°C, 0.75°C
* @n RESOLUTION_0_125 // The decimal part of the obtained temp is a multiple of 0.125 e.g. 0.125°C, 0.250°C, 0.375°C
* @n RESOLUTION_0_0625 // The decimal part of the obtained temp is a multiple of 0.0625 e.g. 0.0625°C, 0.1250°C, 0.1875°C
* @return The set status
* @retval true is set successfully
* @retval false is set parameter error
*/
bool setResolution(uint8_t resolution);
/**
* @fn getResolution
* @brief Get resolution of the temperature sensor, the accuracy of the acquired temp is different in different resolution
* @return resolution
* @retval RESOLUTION_0_5 // The decimal part of the obtained temp is a multiple of 0.5 e.g. 0.5°C, 1.0°C, 1.5°C
* @retval RESOLUTION_0_25 // The decimal part of the obtained temp is a multiple of 0.25 e.g. 0.25°C, 0.50°C, 0.75°C
* @retval RESOLUTION_0_125 // The decimal part of the obtained temp is a multiple of 0.125 e.g. 0.125°C, 0.250°C, 0.375°C
* @retval RESOLUTION_0_0625 // The decimal part of the obtained temp is a multiple of 0.0625 e.g. 0.0625°C, 0.1250°C, 0.1875°C
*/
uint8_t getResolution(void);
/**
* @fn getTemperature
* @brief Get the current ambient temp, note that different temp accuracy can be obtained by setting different resolution
* @return The temp value is a floating point, default to reserve two decimal places, unit is °C
*/
float getTemperature(void);
/**
* @fn getComparatorState
* @brief Get the current comparator status and temp data, which works only in comparator mode
* @return Struct for storing the current data
* @n temperate // Current temp
* @n state // Character string of the comparator status, compare the current temp with the upper threshold, lower threshold, and threshold value
* @n value // Value of the comparator status, explained as follows
* @n TA for current temp, TCRIT for critical temp, TUPPER for maximum temp, TLOWER for minimum temp
* @n 1 for TA ≥ TCRIT, TA > TUPPER, TA < TLOWER
* @n 0 for TA < TCRIT, TA ≤ TUPPER, TA ≥ TLOWER
* @n ------------------------------------
* @n | bit7 ~ bit3 | bit2 | bit1 | bit0 |
* @n ------------------------------------
* @n | reserved | 0 | 0 | 0 |
* @n ------------------------------------
*/
sComparator_t getComparatorState(void);
/**
* @fn setLockState
* @brief Set lock mode or unlock, prevent wrong operations that may change upper limit, lower limit and threshold value, and unlock only by power-off reset after locking
* @param lock
* @n CRIT_LOCK // Lock threshold value, which is not allowed to be changed
* @n WIN_LOCK // Lock upper and lower thresholds, which are not allowed to be changed
* @n CRIT_WIN_LOCK // Lock threshold value, upper and lower limit, which are not allowed to be changed
* @n NO_LOCK // No locking of threshold value, upper and lower limit
* @return bool type return the set status
* @retval true is set successfully
* @retval false is set parameter error
*/
bool setLockState(uint8_t lock);
/**
* @fn getLockState
* @brief Get locking status, to determine if upper limit, lower limit, and threshold can be changed
* @return Locking status
* @retval CRIT_LOCK // Lock threshold value, which is not allowed to be changed
* @retval WIN_LOCK // Lock upper and lower thresholds, which are not allowed to be changed
* @retval CRIT_WIN_LOCK // Lock threshold and the window at the same time, upper limit, lower limit, and threshold are all not allowed to be changed
* @retval NO_LOCK // No locking, threshold value, upper and lower limit are all can be changed
*/
uint8_t getLockState(void);
/**
* @fn setAlertHysteresis
* @brief Set alert temp hysteresis range, add a range to the upper limit, lower limit and threshold, hysteresis function is only applicable to reduce temperature(from hot to cold),
* @details i.e, ALE level will be restored only when the temp reaches the value obtained by subtracting hysteresis temp from the upper limit/lower limit/threshold
* @details For example: maximum temp is 30.0°C, hysteresis temp is +1.5°C, the current temp is 35°C and ALE level has flipped,
* @details the temp must reach 30-1.5=28.5°C before restoring ALE level
* @param mode
* @n HYSTERESIS_0_0 // No hysteresis, there is respond when reaching the specified temp
* @n HYSTERESIS_1_5 // 1.5℃ lag from hot to cold
* @n HYSTERESIS_3_0 // 3.0℃ lag from hot to cold
* @n HYSTERESIS_6_0 // 6.0℃ lag from hot to cold
* @return uint8_t type
* @retval 0x00 is set successfully
* @retval 0xFE is set parameter error
* @retval 0xFF is register lock, not allowed to be modified
*/
uint8_t setAlertHysteresis(uint8_t mode);
/**
* @fn getAlertHysteresis
* @brief Get hysteresis temp
* @return hysteresis type
* @retval HYSTERESIS_0_0 // Temp hysteresis range +0.0℃
* @retval HYSTERESIS_1_5 // Temp hysteresis range +1.5℃
* @retval HYSTERESIS_3_0 // Temp hysteresis range +3.0℃
* @retval HYSTERESIS_6_0 // Temp hysteresis range +6.0℃
*/
uint8_t getAlertHysteresis(void);
/**
* @fn setPolarity
* @brief Set pin ALE polarity, high polarity: pin ALE is active on high, the default is low level, which turns to high when alert occurs.
* @details low polarity: pin ALE is active on low, the default is high level, which turns to low when alert occurs.
* @param polarity
* @n POLARITY_HIGH // pin ALE is active on high
* @n POLARITY_LOW // pin ALE is active on low
* @return state
* @retval 0x00 is set successfully
* @retval 0xFE is set parameter error
* @retval 0xFF is register lock, not allowed to be modified
*/
uint8_t setPolarity(uint8_t polarity);
/**
* @fn getPolarityState
* @brief Get pin ALE polarity, high polarity: pin ALE is active on high, the default is low level, which turns to high when alert occurs.
* @details low polarity: pin ALE is active on low, the default is high level, which turns to low when alert occurs.
* @return polarity
* @retval POLARITY_HIGH // pin ALE is active on high
* @retval POLARITY_LOW // pin ALE is active on low
*/
uint8_t getPolarityState(void);
/**
* @fn setAlertOutputMode
* @brief Set alert output mode, clearing interrupt is not required in comparator output mode, but required in interrupt mode
* @param mode:
* @n COMPARATOR_OUTPUT_MODE // clearing interrupt is not required in comparator output mode,
* @n For example: set pin ALE to be active on low, when the temp exceeds the upper limit alert temp, pin ALE level turns from high to low; when it's below the upper but above the lower limit, pin ALE level turns back to high
* @n INTERRPUT_OUTPUT_MODE // clearing interrupt is required in interrupt mode, when an alert occurs, the interrupt keep existing if it's not cleared, triggering interrupt mode indicates one status to another,
* @n For example, set lower threshold to be 20°C, upper threshold 25°C, and threshold 30°C, no interrupt occurs when temp is below 20°C; when temp exceeds 25°C, interrupt occurs and pin ALE jump, the interrupt should be cleared at the time and pin ALE is restored; in the special case, when pin ALE is above the critical temp of 30°C, the interrupt mode and clearing interrupt are both invalid, the interrupt mode will be restored only when the temp drops below 30 degrees.
* @n DISABLE_OUTPUT_MODE // After disabling output mode, no alert occurs and pin ALE is invalid
* @return state
* @retval 0x00 is set successfully
* @retval 0xFE is set parameter error
* @retval 0xFF is register lock, not allowed to be modified
*/
uint8_t setAlertOutputMode(uint8_t mode);
/**
* @fn getAlertOutputMode
* @brief Get alert output mode
* @return mode
* @retval COMPARATOR_OUTPUT_MODE // Comparator output mode
* @retval INTERRPUT_OUTPUT_MODE // Interrupt output mode
* @retval DISABLE_OUTPUT_MODE // Disable output mode
*/
uint8_t getAlertOutputMode(void);
/**
* @fn setAlertResponseMode
* @brief Set alert response mode, respond to upper & lower limits and threshold; or only respond to threshold, which is inapplicable to interrupt mode
* @param mode
* @n UPPER_LOWER_CRIT_RESPONSE // respond to upper/lower limits and threshold
* @n ONLY_CRIT_RESPONSE // disable upper/lower limits response, only enable threshold response
* @return state
* @retval 0x00 is set successfully
* @retval 0xFE is set parameter error
* @retval 0xFF is register lock, not allowed to be modified
*/
uint8_t setAlertResponseMode(uint8_t mode);
/**
* @fn getAlertResponseMode
* @brief Get interrupt response mode
* @return mode
* @retval UPPER_LOWER_CRIT_RESPONSE // respond to upper/lower limits and threshold
* @retval ONLY_CRIT_RESPONSE // disable upper/lower limits response, only enable threshold response
*/
uint8_t getAlertResponseMode(void);
/**
* @fn setThreshold
* @brief Set threshold value, the upper and lower thresholds, and respond according to the configured interrupt mode
* @details Responding interrupt when the temp is above the upper limit, below the lower limit and above the threshold
* @details The critical temp must be above the upper limit
* @details the upper limit temp must be 2℃ higher than the lower limit temp
* @param crit // Temp threshold, up to two decimal places, automatically processed to multiples of 0.25, range is from -40 to +125℃
* @param upper // Upper limit temp, up to two decimal places, automatically processed to multiples of 0.25, range is from -40 to +125℃
* @param lower // Lower limit temp, up to two decimal places, automatically processed to multiples of 0.25, range is from -40 to +125℃
* @return state
* @retval 0x00 is set successfully
* @retval 0xFD // Upper limit temp is below lower limit, or (upper limit temp - lower limit temp < 2)
* @retval 0xFE // Upper limit temp is below threshold
* @retval 0xFF is register lock, not allowed to be modified
*/
uint8_t setThreshold(float crit, float upper, float lower);
/**
* @fn clearInterrupt
* @brief Clear interrupt, only used in interrupt mode, not work in other modes
*/
void clearInterrupt(void);
protected:
/**
* @fn sensorInit
* @brief Initialize sensor, comtrast sensor chip id with manufacturer id
* @return state
* @retval true is init successfully
* @retval flase is sensor chip id and manufacturer id error
*/
bool sensorInit(void);
/**
* @fn setPowerMode
* @brief Set power mode, power up mode: in this mode, the register can be accessed and the temp can be obtained normally.
* @details Low power mode: temp measurement stop and the register can be read or written, but bus activity will cause higher power consumption
* @param mode
* @n POWER_UP_MODE // power up mode
* @n LOW_POWER_MODE // low power mode
* @return The set status
* @retval true is set success
* @retval false is register lock, not allowed to be modified
*/
bool setPowerMode(uint8_t mode);
/**
* @fn setAlertEnable
* @brief Enable or disable alert mode, after enabling it, pin ALE will jump when satisfying the alert condition; if disabling it, pin ALE has no response.
* @param mode
* @n ENABLE_ALERT // after enabling alert mode, pin ALE will jump when satisfying the alert condition
* @n DISABLE_ALERT // when disabling alert mode, pin ALE has no response
* @return state
* @retval 0x00 is set successfully
* @retval 0xFE is set parameter error
* @retval 0xFF is register lock, not allowed to be modified
*/
uint8_t setAlertEnable(uint8_t mode);
/**
* @fn getAlertEnableState
* @brief Get the alert mode status, enable alert mode or disable it
* @return mode
* @retval ENABLE_ALERT // enable alert mode
* @retval DISABLE_ALERT // disable alert mode
*/
uint8_t getAlertEnableState(void);
/**
* @fn parsingDecimal
* @brief Parse floating point, used to set the floating point of upper/lower limit and threshold
* @return Binary floating point
*/
uint8_t parsingDecimal(float value);
/**
* @fn getManufacturerID
* @brief get manufacturer id
* @return manufacturer id
* @retval true // manufacturer id is true
* @retval false // manufacturer id is false
*/
bool getManufacturerID(void);
/**
* @fn getDeviceID
* @brief get device id
* @return device id
* @retval true // device id is true
* @retval false // device id is false
*/
bool getDeviceID(void);
/**
* @fn dataThreshold
* @brief Parse the integer portion of the threshold, and place it in the specified position
* @param value The threshold data to be placed
* @param data The address to place
*/
Principle
The MCP9808 measures temperature using an internal precision band-gap sensor. It continuously monitors the temperature and compares the measured value against user-defined boundary limits stored in programmable registers. When the temperature crosses these limits, the sensor generates an Alert signal. The Alert output can operate as an active-low or active-high comparator output (thermostat mode) or as an interrupt signal for microcontroller-based systems.
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