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0.2.2 CHT8305

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Rob Tillaart 2024-09-22 11:42:37 +02:00
parent ee4497e49a
commit 054d79afa9
11 changed files with 475 additions and 129 deletions
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12
libraries/CHT8305/CHANGELOG.md
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@ -6,12 +6,22 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
and this project adheres to [Semantic Versioning](http://semver.org/).
## [0.2.2] - 2024-09-16
- Fix #15, improve error handling.
- add return value **CHT8305_ERROR_BUFSIZE**
- add return value **CHT8305_ERROR_GENERIC**
- add return value **0xFFFF** for 2 functions.
- set default values 0.0 for **offset** parameters.
- fix missing names in keywords.txt
- add plotter and performance example
- update readme.md.
## [0.2.1] - 2024-01-30
- add multiplexing section to readme.md
- update examples (URL)
- minor edits
## [0.2.0] - 2023-12-05
- refactor API, constructor, begin()
- update readme.md

151
libraries/CHT8305/CHT8305.cpp
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@ -1,7 +1,7 @@
//
// FILE: CHT8305.cpp
// AUTHOR: Rob Tillaart
// VERSION: 0.2.1
// VERSION: 0.2.2
// PURPOSE: Arduino library for CHT8305 temperature and humidity sensor
// URL: https://github.com/RobTillaart/CHT8305
@ -17,14 +17,24 @@ CHT8305::CHT8305(const uint8_t address, TwoWire *wire)
{
_wire = wire;
_address = address;
_error = CHT8305_OK;
}
int CHT8305::begin()
{
if ((_address < 0x40) || (_address > 0x43)) return CHT8305_ERROR_ADDR;
if (! isConnected()) return CHT8305_ERROR_CONNECT;
return CHT8305_OK;
if ((_address < 0x40) || (_address > 0x43))
{
_error = CHT8305_ERROR_ADDR;
return _error;
}
if (! isConnected())
{
_error = CHT8305_ERROR_CONNECT;
return _error;
}
_error = CHT8305_OK;
return _error;
}
@ -50,27 +60,33 @@ int CHT8305::read()
// do not read too fast
if (millis() - _lastRead < 1000)
{
return CHT8305_ERROR_LASTREAD;
_error = CHT8305_ERROR_LASTREAD;
return _error;
}
_lastRead = millis();
uint8_t data[4] = {0, 0, 0, 0 };
_readRegister(CHT8305_REG_TEMPERATURE, &data[0], 4);
if (_readRegister(CHT8305_REG_TEMPERATURE, &data[0], 4) != CHT8305_OK)
{
return _error;
}
uint16_t tmp = data[0] << 8 | data[1];
uint16_t tmp = (data[0] << 8) | data[1];
_temperature = tmp * (165.0 / 65535.0) - 40.0;
tmp = data[2] << 8 | data[3];
tmp = (data[2] << 8) | data[3];
_humidity = tmp * (1.0 / 655.35); // == / 65535 * 100%
if (_tempOffset != 0.0) _temperature += _tempOffset;
if (_humOffset != 0.0)
if (_humOffset != 0.0)
{
_humidity += _humOffset;
if (_humidity < 0.0) _humidity = 0.0;
if (_humidity > 100.0) _humidity = 100.0;
}
return CHT8305_OK;
_error = CHT8305_OK;
return _error;
}
@ -79,14 +95,18 @@ int CHT8305::readTemperature()
// do not read too fast
if (millis() - _lastRead < 1000)
{
return CHT8305_ERROR_LASTREAD;
_error = CHT8305_ERROR_LASTREAD;
return _error;
}
_lastRead = millis();
uint8_t data[2] = {0, 0};
_readRegister(CHT8305_REG_TEMPERATURE, &data[0], 2);
if (_readRegister(CHT8305_REG_TEMPERATURE, &data[0], 2) != CHT8305_OK)
{
return _error;
}
uint16_t tmp = data[0] << 8 | data[1];
uint16_t tmp = (data[0] << 8) | data[1];
_temperature = tmp * (165.0 / 65535.0) - 40.0;
if (_tempOffset != 0.0)
@ -94,7 +114,8 @@ int CHT8305::readTemperature()
_temperature += _tempOffset;
}
return CHT8305_OK;
_error = CHT8305_OK;
return _error;
}
@ -103,14 +124,18 @@ int CHT8305::readHumidity()
// do not read too fast
if (millis() - _lastRead < 1000)
{
return CHT8305_ERROR_LASTREAD;
_error = CHT8305_ERROR_LASTREAD;
return _error;
}
_lastRead = millis();
uint8_t data[2] = {0, 0};
_readRegister(CHT8305_REG_HUMIDITY, &data[0], 2);
if (_readRegister(CHT8305_REG_HUMIDITY, &data[0], 4) != CHT8305_OK)
{
return _error;
}
uint16_t tmp = data[0] << 8 | data[1];
uint16_t tmp = (data[0] << 8) | data[1];
_humidity = tmp * (1.0 / 655.35); // == / 65535 * 100%
if (_humOffset != 0.0)
@ -120,7 +145,8 @@ int CHT8305::readHumidity()
if (_humidity > 100.0) _humidity = 100.0;
}
return CHT8305_OK;
_error = CHT8305_OK;
return _error;
}
@ -184,20 +210,27 @@ float CHT8305::getTemperatureOffset()
//
// CONFIGURATION REGISTER
//
void CHT8305::setConfigRegister(uint16_t bitmask)
bool CHT8305::setConfigRegister(uint16_t bitmask)
{
uint8_t data[2];
data[0] = bitmask >> 8;
data[1] = bitmask & 0xFF;
_writeRegister(2, &data[0], 2);
if (_writeRegister(2, &data[0], 2) != CHT8305_OK)
{
return false;
}
return true;
}
uint16_t CHT8305::getConfigRegister()
{
uint8_t data[2] = { 0, 0};
_readRegister(CHT8305_REG_CONFIG, &data[0], 2);
uint16_t tmp = data[0] << 8 | data[1];
if (_readRegister(CHT8305_REG_CONFIG, &data[0], 2) != CHT8305_OK)
{
return 0;
}
uint16_t tmp = (data[0] << 8) | data[1];
return tmp;
}
@ -344,7 +377,10 @@ bool CHT8305::setAlertLevels(float temperature, float humidity)
tmp = (temperature + 40.0) * (511.0 / 165.0);
mask |= tmp;
_writeRegister(CHT8305_REG_ALERT, (uint8_t *)&mask, 2);
if (_writeRegister(CHT8305_REG_ALERT, (uint8_t *)&mask, 2) != CHT8305_OK)
{
return false;
}
return true;
}
@ -352,7 +388,10 @@ bool CHT8305::setAlertLevels(float temperature, float humidity)
float CHT8305::getAlertLevelTemperature()
{
uint16_t data = 0;
_readRegister(CHT8305_REG_ALERT, (uint8_t *)&data, 2);
if (_readRegister(CHT8305_REG_ALERT, (uint8_t *)&data, 2) != CHT8305_OK)
{
return CHT8305_ERROR_GENERIC;
}
data &= 0x01FF;
data <<= 7;
return data * (165.0 / 65535.0) - 40.0;
@ -362,7 +401,10 @@ float CHT8305::getAlertLevelTemperature()
float CHT8305::getAlertLevelHumidity()
{
uint16_t data = 0;
_readRegister(CHT8305_REG_ALERT, (uint8_t *)&data, 2);
if (_readRegister(CHT8305_REG_ALERT, (uint8_t *)&data, 2) != CHT8305_OK)
{
return CHT8305_ERROR_GENERIC;
}
data &= 0xFE00;
return data * (100.0 / 65535.0);
}
@ -375,8 +417,11 @@ float CHT8305::getAlertLevelHumidity()
float CHT8305::getVoltage()
{
uint8_t data[2] = { 0, 0};
_readRegister(CHT8305_REG_VOLTAGE, &data[0], 2);
uint16_t tmp = data[0] << 8 | data[1];
if (_readRegister(CHT8305_REG_VOLTAGE, &data[0], 2) != CHT8305_OK)
{
return CHT8305_ERROR_GENERIC;
}
uint16_t tmp = (data[0] << 8) | data[1];
return tmp * (5.0 / 32768.0); // best guess
}
@ -388,8 +433,11 @@ float CHT8305::getVoltage()
uint16_t CHT8305::getManufacturer()
{
uint8_t data[2] = { 0, 0};
_readRegister(CHT8305_REG_MANUFACTURER, &data[0], 2);
uint16_t tmp = data[0] << 8 | data[1];
if (_readRegister(CHT8305_REG_MANUFACTURER, &data[0], 2) != CHT8305_OK)
{
return 0xFFFF;
}
uint16_t tmp = (data[0] << 8) | data[1];
return tmp;
}
@ -397,12 +445,23 @@ uint16_t CHT8305::getManufacturer()
uint16_t CHT8305::getVersionID()
{
uint8_t data[2] = { 0, 0};
_readRegister(CHT8305_REG_VERSION, &data[0], 2);
uint16_t tmp = data[0] << 8 | data[1];
if (_readRegister(CHT8305_REG_VERSION, &data[0], 2) != CHT8305_OK)
{
return 0xFFFF;
}
uint16_t tmp = (data[0] << 8) | data[1];
return tmp;
}
int CHT8305::getLastError()
{
int e = _error;
_error = CHT8305_OK;
return e;
}
////////////////////////////////////////////////
//
// PRIVATE
@ -412,7 +471,11 @@ int CHT8305::_readRegister(uint8_t reg, uint8_t * buf, uint8_t size)
_wire->beginTransmission(_address);
_wire->write(reg);
int n = _wire->endTransmission();
if (n != 0) return CHT8305_ERROR_I2C;
if (n != 0)
{
_error = CHT8305_ERROR_I2C;
return _error;
}
if (reg == CHT8305_REG_TEMPERATURE) // wait for conversion...
{
@ -420,14 +483,17 @@ int CHT8305::_readRegister(uint8_t reg, uint8_t * buf, uint8_t size)
}
n = _wire->requestFrom(_address, size);
if (n == size)
if (n != size)
{
for (uint8_t i = 0; i < size; i++)
{
buf[i] = _wire->read();
}
_error = CHT8305_ERROR_BUFSIZE;
return _error;
}
return CHT8305_OK;
for (uint8_t i = 0; i < size; i++)
{
buf[i] = _wire->read();
}
_error = CHT8305_OK;
return _error;
}
@ -440,8 +506,13 @@ int CHT8305::_writeRegister(uint8_t reg, uint8_t * buf, uint8_t size)
_wire->write(buf[i]);
}
int n = _wire->endTransmission();
if (n != 0) return CHT8305_ERROR_I2C;
return CHT8305_OK;
if (n != 0)
{
_error = CHT8305_ERROR_I2C;
return _error;
}
_error = CHT8305_OK;
return _error;
}

53
libraries/CHT8305/CHT8305.h
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@ -2,7 +2,7 @@
//
// FILE: CHT8305.h
// AUTHOR: Rob Tillaart
// VERSION: 0.2.1
// VERSION: 0.2.2
// PURPOSE: Arduino library for CHT8305 temperature and humidity sensor
// URL: https://github.com/RobTillaart/CHT8305
//
@ -12,30 +12,34 @@
#include "Wire.h"
#define CHT8305_LIB_VERSION (F("0.2.1"))
#define CHT8305_LIB_VERSION (F("0.2.2"))
// DEFAULT ADDRESS
#ifndef CHT8305_DEFAULT_ADDRESS
#define CHT8305_DEFAULT_ADDRESS 0x40
#endif
// ERRORS
#define CHT8305_OK 0
#define CHT8305_ERROR_ADDR -10
#define CHT8305_ERROR_I2C -11
#define CHT8305_ERROR_CONNECT -12
#define CHT8305_ERROR_BUFSIZE -13
#define CHT8305_ERROR_LASTREAD -20
#define CHT8305_ERROR_GENERIC -999
// REGISTERS
#define CHT8305_REG_TEMPERATURE 0x00
#define CHT8305_REG_HUMIDITY 0x01
#define CHT8305_REG_CONFIG 0x02
#define CHT8305_REG_ALERT 0x03
#define CHT8305_REG_VOLTAGE 0x04
#define CHT8305_REG_MANUFACTURER 0xFE
#define CHT8305_REG_VERSION 0xFF
// REGISTER MASKS
// REGISTERS (in .h for build-CI test)
#define CHT8305_REG_TEMPERATURE 0x00
#define CHT8305_REG_HUMIDITY 0x01
#define CHT8305_REG_CONFIG 0x02
#define CHT8305_REG_ALERT 0x03
#define CHT8305_REG_VOLTAGE 0x04
#define CHT8305_REG_MANUFACTURER 0xFE
#define CHT8305_REG_VERSION 0xFF
// REGISTER MASKS (in .h for build-CI test)
#define CHT8305_CFG_SOFT_RESET 0x8000
#define CHT8305_CFG_CLOCK_STRETCH 0x4000
#define CHT8305_CFG_HEATER 0x2000
@ -78,15 +82,16 @@ public:
// adding offsets works well in normal range
void setHumidityOffset(float offset);
void setHumidityOffset(float offset = 0.0);
// might introduce under- or overflow at the ends of the sensor range
void setTemperatureOffset(float offset);
void setTemperatureOffset(float offset = 0.0);
float getHumidityOffset();
float getTemperatureOffset();
// CONFIGURATION REGISTER
void setConfigRegister(uint16_t bitmask);
// default configRegister = 0x1004 (explicit no default parameter)
bool setConfigRegister(uint16_t bitmask);
uint16_t getConfigRegister();
//
// | bit | mask | name | description |
@ -132,13 +137,12 @@ public:
void setVCCenable(bool enable = true);
bool getVCCenable();
// ALERT FUNCTIONS
// mode trigger
// 0 T or H (default)
// 1 T
// 2 H
// 3 T and H
// ALERT FUNCTIONS
// mode trigger
// 0 T or H (default)
// 1 T
// 2 H
// 3 T and H
bool setAlertTriggerMode(uint8_t mode = 0);
uint8_t getAlertTriggerMode();
bool getAlertPendingStatus();
@ -153,6 +157,8 @@ public:
// VOLTAGE
// one need to call setVCCenable(true) first.
// meaning of this function is unclear.
float getVoltage();
@ -161,6 +167,9 @@ public:
uint16_t getVersionID(); // may vary
// ERROR HANDLING
int getLastError();
private:
float _humOffset = 0.0;
float _tempOffset = 0.0;
@ -177,6 +186,8 @@ private:
void _setConfigMask(uint16_t mask);
void _clrConfigMask(uint16_t mask);
int _error = CHT8305_OK;
};

194
libraries/CHT8305/README.md
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@ -15,7 +15,8 @@ Arduino library for CHT8305 temperature and humidity sensor.
**EXPERIMENTAL** minimal tested.
If you are able to test this library, please let me know your experiences.
If you are able to test this library, please let me know
your experiences.
## Description
@ -34,25 +35,25 @@ One of the interesting functions is the support of an ALERT function.
This prevents the need for continuous polling of the sensor.
#### 0.2.0 Breaking change
### 0.2.0 Breaking change
Version 0.2.0 introduced a breaking change.
You cannot set the pins in **begin()** any more.
This reduces the dependency of processor dependent Wire implementations.
The user has to call **Wire.begin()** and can optionally set the Wire pins
The user has to call **Wire.begin()** and can optionally set the Wire pins
before calling **begin()**.
Moved the address parameter from **begin()** to constructor.
#### Tests
### Tests
- Temperature and humidity functions works on AVR.
- default about 14 milliseconds at 14 bit resolution.
- offset functions work.
- getVoltage() function works on AVR but meaning unclear.
- getManufacturer(), getVersionID() works on AVR.
-
-
The ALERT functions are not tested.
The reason is that the sensor I have does not expose the ALERT pin.
@ -86,20 +87,43 @@ Always check datasheet for connections.
Pull ups are needed on SDA, SCL and optional to ALERT.
#### Alert
### Alert
The CHT8305 has an ALERT logic output pin with an open drain structure.
This output is active low. (if the breakout supports this.)
## I2C
## I2C
#### performance
### performance
I2C bus speeds is supported up to 400 KHz.
I2C bus speeds is supported up to 400 kHz.
In practice the sensor seems to work even at 800 kHz.
However not clear if the higher speed brings extra wear?
As the sensor / library blocks on reading the temperature
using high I2C speeds does not make a difference, except
for reading Humidity.
So a higher I2C speed does not help to read this sensor.
See - HT8305_performance.ino
#### Addresses
| SPEED | READ | READ_T | READ_H |
|:--------:|:-------:|:--------:|:--------:|
| 100000 | 14824 | 14604 | 376 |
| 200000 | 14476 | 14360 | 224 |
| 300000 | 14368 | 14276 | 172 |
| 400000 | 14324 | 14244 | 148 |
| 500000 | 14300 | 14224 | 140 |
| 600000 | 14276 | 14212 | 132 |
| 700000 | 14272 | 14204 | 124 |
| 800000 | 14268 | 14196 | 120 |
### Addresses
| AD0 | Address | Notes |
|:-----:|:----------:|:--------|
@ -111,19 +135,19 @@ I2C bus speeds is supported up to 400 KHz.
Pull ups are needed on SDA, SCL and optional to ALERT.
#### I2C multiplexing
### I2C multiplexing
Sometimes you need to control more devices than possible with the default
address range the device provides.
This is possible with an I2C multiplexer e.g. TCA9548 which creates up
to eight channels (think of it as I2C subnets) which can use the complete
address range of the device.
This is possible with an I2C multiplexer e.g. TCA9548 which creates up
to eight channels (think of it as I2C subnets) which can use the complete
address range of the device.
Drawback of using a multiplexer is that it takes more administration in
your code e.g. which device is on which channel.
Drawback of using a multiplexer is that it takes more administration in
your code e.g. which device is on which channel.
This will slow down the access, which must be taken into account when
deciding which devices are on which channel.
Also note that switching between channels will slow down other devices
Also note that switching between channels will slow down other devices
too if they are behind the multiplexer.
- https://github.com/RobTillaart/TCA9548
@ -135,16 +159,16 @@ too if they are behind the multiplexer.
#include "CHT8305.h"
```
#### Constructor
### Constructor
- **CHT8305(const uint8_t address = CHT8305_DEFAULT_ADDRESS, TwoWire \*wire = &Wire)** Constructor
with default address (0x40) and I2C bus.
- **CHT8305(const uint8_t address = CHT8305_DEFAULT_ADDRESS, TwoWire \*wire = &Wire)**
Constructor with default address (0x40) and I2C bus.
- **int begin()** initializes internals.
Returns error status.
- **bool isConnected()** checks if address (default 0x40) can be seen on the I2C bus.
#### Core
### Core
- **int read()** reads both the temperature and humidity.
Can be called once per second.
@ -153,49 +177,63 @@ Can be called once per second.
- **uint32_t lastRead()** returns lastRead in MilliSeconds since start sketch.
Useful to check when it is time to call **read()** again, or for logging.
- **float getHumidity()** returns last humidity read.
Will return the same value until **read()** or **readTemperature()** is called again.
- **float getTemperature()** returns last temperature read.
Will return the same value until **read()** or **readHumidity()** is called again.
- **float getTemperature()** returns last temperature read.
Will return the same value until **read()** or **readTemperature()** is called again.
Note: read(), readTemperature() and readHumidity() blocks each other,
Note: **read()**, **readTemperature()** and **readHumidity()** block each other,
so you can call only one of them every second.
#### Conversion delay
### Conversion delay
- **void setConversionDelay(uint8_t cd = 14)** default is 14 milliseconds (datasheet).
7 ms failed. 8 ms worked, so values below 8 are mapped to 8 in the library.
Expect 10 ms is pretty save. Use at own risk.
- **void setConversionDelay(uint8_t cd = 14)** default is 14 milliseconds
(from the datasheet). 7 milliseconds failed and 8 milliseconds worked.
So values below 8 milliseconds are mapped to 8 in the library.
Expect that 10 milliseconds is a pretty save value to work with.
Adjust this setting at your own risk.
It might be that lower resolutions allow shorter delays. This is not tested.
- **uint8_t getConversionDelay()** returns set value.
- **uint8_t getConversionDelay()** returns the default (14) or last set value.
#### Offset
### Offset
Adding offsets works well in the "normal range" but might introduce
Adding offsets works well in the "normal range" but might introduce
under- or overflow at the ends of the sensor range.
These are not handled for temperature by the library (humidity since 0.1.7).
- **void setHumidityOffset(float offset)** idem.
- **void setTemperatureOffset(float offset)** idem.
- **void setHumidityOffset(float offset = 0.0)** idem. Default is set to
zero, for an easy reset off the offset.
There is no range check in this function, however, **read()** will
keep the value between 0 and 100%.
- **void setTemperatureOffset(float offset = 0.0)** idem. Default is set to
zero, for an easy reset off the offset.
There is no range check in this function.
- **float getHumidityOffset()** idem.
- **float getTemperatureOffset()** idem.
If the offset is not the same over the operational range,
If the offset is not the same over the operational range,
consider a mapping function for temperature and humidity.
e.g. https://github.com/RobTillaart/MultiMap
#### Configuration register
### Configuration register
Check the datasheet for details of the register bits.
- **void setConfigRegister(uint16_t bitmask)** idem. Default value 0x1004.
- **uint16_t getConfigRegister()** idem.
- **bool setConfigRegister(uint16_t bitmask)** See table below.
Default value 0x1004.
Returns false if write to the config register fails.
Check **getLastError()** for possible cause.
- **uint16_t getConfigRegister()** idem.
If 0x0000 is returned it may indicate an error.
Check **getLastError()** for possible cause.
Bits of configRegister, check datasheet for details.
| bit | mask | name | description |
|:-----:|:------:|:----------------|:--------------|
| 15 | 0x8000 | soft reset | 1 = reboot the sensor to default
| 15 | 0x8000 | soft reset | 1 = reboot the sensor to default
| 14 | 0x4000 | clock stretch | 1 = ON, 0 = OFF (default)
| 13 | 0x2000 | heater | 1 = ON, 0 = OFF (default)
| 12 | 0x1000 | mode | 1 = read both (default), 0 = read T or RH
@ -207,39 +245,40 @@ Check the datasheet for details of the register bits.
| 4 | 0x0010 | H-ALT | Humidity Alert status
| 3 | 0x0008 | T-ALT | Temperature Alert status
| 2 | 0x0004 | VCC enable | 1 = enable VCC measurement (default), 0 = disable
| 1-0 | 0x0003 | reserved. | do not change.
| 1-0 | 0x0003 | reserved. | do not change.
#### Getters / setters configuration register
### Getters / setters configuration register
Note: setting **setConfigRegister(bitmask)** can be faster.
Wrapper functions for easy configuration.
Wrapper functions for easy configuration. Read the datasheet for the details.
- **void softReset()** sets the soft reset bit in the configuration, causing the sensor to reset.
- **void softReset()** sets the soft reset bit in the configuration,
causing the sensor to reset.
- **void setI2CClockStretch(bool on = false)** check datasheet.
- **bool getI2CClockStretch()** check datasheet.
- **void setHeaterOn(bool on = false)** switch on internal heater.
- **void setHeaterOn(bool on = false)** switch on internal heater.
Can improve humidity readings.
See datasheet for (limited) details.
- **WARNING** User is responsible for timing as library does not support timing.
- **bool getHeater()** Returns status of the heater.
- **void setMeasurementMode(bool both = true)** both T and H or single value.
- **bool getMeasurementMode()** returns mode set above.
- **bool getMeasurementMode()** returns mode set above.
- **bool getVCCstatus()** 1 == > 2.8V 0 == < 2.8V Useful when battery operated?
- **void setTemperatureResolution(uint8_t res = 0)** 1 = 11 bit, 0 = 14 bit (default).
- **uint8_t getTemperatureResolution()** idem.
- **void setHumidityResolution(uint8_t res = 0)** 2 = 8 bit, 1 = 11 bit, 0 = 14 bit (default).
- **uint8_t getHumidityResolution()** idem.
- **void setVCCenable(bool enable = false)** idem.
- **bool getVCCenable()** idem.
- **void setVCCenable(bool enable = false)** enable VCC measurement of the power supply.
- **bool getVCCenable()** return current status of enable bit.
#### Alert
### Alert
See register 3 datasheet page 12 for details.
- **void setAlertTriggerMode(uint8_t mode)** see table below.
- **void setAlertTriggerMode(uint8_t mode = 0)** see table below.
- **uint8_t getAlertTriggerMode()** returns 0, 1, 2 or 3.
| mode | trigger | notes |
@ -252,7 +291,7 @@ See register 3 datasheet page 12 for details.
- **bool getAlertPendingStatus()** idem.
- **bool getAlertHumidityStatus()** idem.
- **bool getAlertTemperatureStatus()** idem.
- **bool setAlertLevels(float temperature, float humidity)**
- **bool setAlertLevels(float temperature, float humidity)**
- the values will be truncated to the nearest value possible.
- the ALERT supports HIGH limit only ==> there is no LOW limit ALERT.
- note: the datasheet is ambiguous with respect to the formula used.
@ -263,27 +302,53 @@ See register 3 datasheet page 12 for details.
The ALERT pin triggers with a falling edge (from HIGH to LOW).
#### Voltage
### Supply voltage
VCC measurement should be enabled by means of **void setVCCenable(true)**
or by **setConfigRegister(0x0004)**.
(datasheet 1.1.5)
The chip has a feature to measure supply voltage (VCC) with 16bit output data.
VCC measurement should be enabled by means of **void setVCCenable(true)**.
- **float getVoltage()** unclear what unit is used.
Best guess for now: 16 bit data implies ```voltage = 5.0V * value / 32768.0;```
Best guess for now: 16 bit data implies ```voltage = 5.0V * value / 32767.0;```
Varied slightly 5.000 - 4.999 also for 3V3 power supply.
Conclusion: it is unclear how to interpret this register.
Conclusion: it is not 100 % clear how to interpret this register.
#### Meta data
### Meta data
- **uint16_t getManufacturer()** returns 0x5959.
- **uint16_t getVersionID()** return value may differ.
- **uint16_t getVersionID()** return value may differ.
Test returned 0x8305.
#### Register map
### Error handling
Since 0.2.2 some error handling has been added.
This need to be improved in the future.
- **getLastError()** returns 0 if all is OK.
If it doesn't return 0 an error occurred during **read()** et al.
The table gives some information where the problem occurred.
A call to **getLastError()** resets the internal error flag.
Note: in case of e.g. an I2C error, the last values of Temperature
and Humidity do not change.
| Error constant | value | Notes |
|:-------------------------|:--------:|:--------|
| CHT8305_OK | 0 |
| CHT8305_ERROR_ADDR | -10 |
| CHT8305_ERROR_I2C | -11 |
| CHT8305_ERROR_CONNECT | -12 |
| CHT8305_ERROR_BUFSIZE | -13 |
| CHT8305_ERROR_LASTREAD | -20 |
| CHT8305_ERROR_GENERIC | -999 |
| | 0xFFFF | patch |
### Register map
See datasheet page 10 for details
@ -303,25 +368,26 @@ See datasheet page 10 for details
#### Must
- elaborate documentation.
- more testing (platforms)
#### Should
- test ESP32, other platforms?
- test performance.
- test other platforms
- ESP32,
- test resolution bits.
- delay ?
- test configuration functions.
- test ALERT functions.
- test write / readRegister with a single uint16_t to simplify code.
- test error handling.
#### Could
- parameter testing
- parameter defaults?
- investigate asynchronous reading
- request, ready (after 15 millis), fetch
- needs lastRequest timestamp
- configRegister => force bit 0 and 1 to 0
#### Wont

83
libraries/CHT8305/examples/CHT8305_performance/CHT8305_performance.ino Normal file
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@ -0,0 +1,83 @@
//
// FILE: CHT8305_performance.ino
// AUTHOR: Rob Tillaart
// PURPOSE: I2C performance for CHT8305 I2C humidity & temperature sensor
// URL: https://github.com/RobTillaart/CHT8305
// Always check datasheet - front view
//
// +---------------+
// VCC ----| VCC |
// SDA ----| SDA CHT8305 | CHECK DATASHEET.
// GND ----| GND |
// SCL ----| SCL |
// ? ----| AD0 | ? depends on address to select
// | |
// IRQ ----| ALERT | only if enabled.
// +---------------+
//
// check datasheet
// VCC RED
// GND BLACK
// SDA YELLOW
// SCL WHITE
#include "CHT8305.h"
CHT8305 CHT(0x40); // CHT8305_DEFAULT_ADDRESS = 0x40
uint32_t start, stop;
void setup()
{
Serial.begin(115200);
Serial.println(__FILE__);
Serial.print("CHT8305_LIB_VERSION: ");
Serial.println(CHT8305_LIB_VERSION);
Serial.println();
delay(100);
Wire.begin();
CHT.begin();
delay(1000);
Serial.println("Note: reading temperature is blocking!\n");
Serial.println("SPEED\tREAD\tREAD_T\tREAD_H");
for (uint32_t speed = 100000; speed <= 800000; speed += 50000)
{
Wire.setClock(speed);
start = micros();
CHT.read();
stop = micros();
Serial.print(speed);
Serial.print("\t");
Serial.print(stop - start);
delay(1000);
start = micros();
CHT.readTemperature();
stop = micros();
Serial.print("\t");
Serial.print(stop - start);
delay(1000);
start = micros();
CHT.readHumidity();
stop = micros();
Serial.print("\t");
Serial.print(stop - start);
Serial.print("\n");
delay(1000);
}
}
void loop()
{
}
// -- END OF FILE --

24
libraries/CHT8305/examples/CHT8305_performance/performance_0.2.2.txt Normal file
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@ -0,0 +1,24 @@
IDE: 1.8.19
Board: Arduino
CHT8305_LIB_VERSION: 0.2.2
Note: reading temperature is blocking!
SPEED READ READ_T READ_H
100000 14824 14604 384
150000 14596 14440 276
200000 14480 14360 224
250000 14416 14312 192
300000 14368 14276 168
350000 14340 14252 156
400000 14332 14244 152
450000 14308 14236 144
500000 14300 14232 140
550000 14284 14212 132
600000 14280 14220 132
650000 14272 14208 128
700000 14268 14204 124
750000 14260 14196 120
800000 14264 14200 120

65
libraries/CHT8305/examples/CHT8305_plotter/CHT8305_plotter.ino Normal file
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@ -0,0 +1,65 @@
//
// FILE: CHT8305_plotter.ino
// AUTHOR: Rob Tillaart
// PURPOSE: Demo for CHT8305 I2C humidity & temperature sensor
// URL: https://github.com/RobTillaart/CHT8305
//
// to be used with Arduino plotter.
//
// Always check datasheet - front view
//
// +---------------+
// VCC ----| VCC |
// SDA ----| SDA CHT8305 | CHECK DATASHEET.
// GND ----| GND |
// SCL ----| SCL |
// ? ----| AD0 | ? depends on address to select
// | |
// IRQ ----| ALERT | only if enabled.
// +---------------+
//
// check datasheet
// VCC RED
// GND BLACK
// SDA YELLOW
// SCL WHITE
#include "CHT8305.h"
CHT8305 CHT(0x40); // CHT8305_DEFAULT_ADDRESS = 0x40
void setup()
{
Serial.begin(115200);
Serial.println(__FILE__);
Serial.print("CHT8305_LIB_VERSION: ");
Serial.println(CHT8305_LIB_VERSION);
Serial.println();
Wire.begin();
Wire.setClock(400000);
CHT.begin();
delay(1000);
}
void loop()
{
if (millis() - CHT.lastRead() >= 1000)
{
// READ DATA
CHT.read();
Serial.print(CHT.getLastError());
Serial.print('\t');
Serial.print(CHT.getHumidity());
Serial.print('\t');
Serial.println(CHT.getTemperature());
}
}
// -- END OF FILE --

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libraries/CHT8305/keywords.txt
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@ -7,11 +7,15 @@ CHT8305 KEYWORD1
# Methods and Functions (KEYWORD2)
begin KEYWORD2
isConnected KEYWORD2
getAddress KEYWORD2
read KEYWORD2
readTemperature KEYWORD2
readHumidity KEYWORD2
lastRead KEYWORD2
getTemperature KEYWORD2
getHumidity KEYWORD2
getTemperature KEYWORD2
setConversionDelay KEYWORD2
getConversionDelay KEYWORD2
@ -50,8 +54,20 @@ setAlertLevels KEYWORD2
getAlertLevelTemperature KEYWORD2
getAlertLevelHumidity KEYWORD2
getVoltage KEYWORD2
getManufacturer KEYWORD2
getVersionID KEYWORD2
# Constants (LITERAL1)
CHT8305_LIB_VERSION LITERAL1
CHT8305_DEFAULT_ADDRESS LITERAL1
CHT8305_OK LITERAL1
CHT8305_ERROR_ADDR LITERAL1
CHT8305_ERROR_I2C LITERAL1
CHT8305_ERROR_CONNECT LITERAL1
CHT8305_ERROR_LASTREAD LITERAL1

2
libraries/CHT8305/library.json
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@ -15,7 +15,7 @@
"type": "git",
"url": "https://github.com/RobTillaart/CHT8305.git"
},
"version": "0.2.1",
"version": "0.2.2",
"license": "MIT",
"frameworks": "*",
"platforms": "*",

2
libraries/CHT8305/library.properties
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@ -1,5 +1,5 @@
name=CHT8305
version=0.2.1
version=0.2.2
author=Rob Tillaart <rob.tillaart@gmail.com>
maintainer=Rob Tillaart <rob.tillaart@gmail.com>
sentence=Arduino library for CHT8305 temperature and humidity sensor.