Roy van Dam
Humidity and Temperature Sensor - Sensirion SHT1x driver
Dependents: ProgrammePrincipal Wetterstation project1 4180_Project ... more
Revision 1:8465801be23f, committed 2010-11-19
- Comitter:
- NegativeBlack
- Date:
- Fri Nov 19 16:24:46 2010 +0000
- Parent:
- 0:d55659b0c4a0
- Commit message:
- Added: control over OTP reload
Added: connection reset.
Fixed: invalid humidity conversion when using the lower resolution
Changed in this revision
--- a/i2c.cpp Thu Nov 18 10:23:43 2010 +0000
+++ b/i2c.cpp Fri Nov 19 16:24:46 2010 +0000
@@ -1,143 +1,153 @@
-/**
- * Copyright (c) 2010 Roy van Dam <roy@negative-black.org>
- * 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.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 "i2c.hpp"
-
-namespace SHTx {
- I2C::I2C(PinName sda, PinName scl) :
- scl_pin(scl), sda_pin(sda), frequency(10) {
- this->sda_pin.output();
- this->scl_pin.output();
- }
-
- void
- I2C::setFrequency(uint32_t hz) {
- this->frequency = (1000000 / hz);
- }
-
- void
- I2C::start(void) {
- this->output();
- this->sda(1);
- this->scl(1);
- this->sda(0);
- this->scl(0);
- this->scl(1);
- this->sda(1);
- this->scl(0);
- }
-
- void
- I2C::stop(void) {
- this->output();
- this->sda(0);
- this->scl(1);
- this->sda(1);
- }
-
- bool
- I2C::wait(void) {
- bool ack = false;
-
- this->input();
- for (uint8_t i = 0; i < 500 && !ack; i++) {
- ack = !this->sda_pin;
- wait_ms(1);
- }
-
- return ack;
- }
-
- bool
- I2C::write(uint8_t data) {
- bool ack;
-
- this->output();
- for (uint8_t i = 8; i; i--) {
- this->shift_out(data & 0x80);
- data <<= 1;
- }
-
- this->input();
- ack = !this->shift_in();
-
- return ack;
- }
-
- uint8_t
- I2C::read(bool ack) {
- uint8_t data = 0;
-
- this->input();
- for (uint8_t i = 8; i; i--) {
- data <<= 1;
- data |= this->shift_in();
- }
-
- this->output();
- this->shift_out(!ack);
-
- return data;
- }
-
- void
- I2C::output(void) {
- this->sda_pin.output();
- }
-
- void
- I2C::input(void) {
- this->sda_pin.input();
- }
-
- void
- I2C::sda(bool value) {
- this->sda_pin = value;
- wait_us(this->frequency);
- }
-
- void
- I2C::scl(bool value) {
- this->scl_pin = value;
- wait_us(this->frequency);
- }
-
- void
- I2C::shift_out(bool bit) {
- this->sda(bit);
- this->scl(1);
- this->scl(0);
- }
-
- bool
- I2C::shift_in(void) {
- wait_us(this->frequency);
- this->scl(1);
- bool bit = this->sda_pin;
- this->scl(0);
- return bit;
- }
+/**
+ * Copyright (c) 2010 Roy van Dam <roy@negative-black.org>
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 "i2c.hpp"
+
+namespace SHTx {
+ I2C::I2C(PinName sda, PinName scl) :
+ scl_pin(scl), sda_pin(sda), frequency(10) {
+ this->sda_pin.output();
+ this->scl_pin.output();
+ }
+
+ void
+ I2C::setFrequency(uint32_t hz) {
+ this->frequency = (1000000 / hz);
+ }
+
+ void
+ I2C::start(void) {
+ this->output();
+ this->sda(1);
+ this->scl(1);
+ this->sda(0);
+ this->scl(0);
+ this->scl(1);
+ this->sda(1);
+ this->scl(0);
+ }
+
+ void
+ I2C::stop(void) {
+ this->output();
+ this->sda(0);
+ this->scl(1);
+ this->sda(1);
+ }
+
+ bool
+ I2C::wait(void) {
+ bool ack = false;
+
+ this->input();
+ for (uint8_t i = 0; i < 500 && !ack; i++) {
+ wait_ms(1);
+ ack = !this->sda_pin;
+ }
+
+ return ack;
+ }
+
+ void
+ I2C::reset(void) {
+ this->output();
+ for (uint8_t i = 9; i; i--) {
+ this->shift_out(1);
+ }
+ this->start();
+ this->scl(1);
+ }
+
+ bool
+ I2C::write(uint8_t data) {
+ bool ack;
+
+ this->output();
+ for (uint8_t i = 8; i; i--) {
+ this->shift_out(data & 0x80);
+ data <<= 1;
+ }
+
+ this->input();
+ ack = !this->shift_in();
+
+ return ack;
+ }
+
+ uint8_t
+ I2C::read(bool ack) {
+ uint8_t data = 0;
+
+ this->input();
+ for (uint8_t i = 8; i; i--) {
+ data <<= 1;
+ data |= this->shift_in();
+ }
+
+ this->output();
+ this->shift_out(!ack);
+
+ return data;
+ }
+
+ void
+ I2C::output(void) {
+ this->sda_pin.output();
+ }
+
+ void
+ I2C::input(void) {
+ this->sda_pin.input();
+ }
+
+ void
+ I2C::sda(bool value) {
+ this->sda_pin = value;
+ wait_us(this->frequency);
+ }
+
+ void
+ I2C::scl(bool value) {
+ this->scl_pin = value;
+ wait_us(this->frequency);
+ }
+
+ void
+ I2C::shift_out(bool bit) {
+ this->sda(bit);
+ this->scl(1);
+ this->scl(0);
+ }
+
+ bool
+ I2C::shift_in(void) {
+ wait_us(this->frequency);
+ this->scl(1);
+ bool bit = this->sda_pin;
+ this->scl(0);
+ return bit;
+ }
}
\ No newline at end of file
--- a/i2c.hpp Thu Nov 18 10:23:43 2010 +0000
+++ b/i2c.hpp Fri Nov 19 16:24:46 2010 +0000
@@ -1,161 +1,168 @@
-/**
- * Copyright (c) 2010 Roy van Dam <roy@negative-black.org>
- * 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.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
- */
-
-#ifndef _I2C_HPP_
-#define _I2C_HPP_
-
-#include "mbed.h"
-
-namespace SHTx {
- /**
- * Class: I2C
- * Humidity and Temperature Sensor - SHT15
- * I2C Bit-bang master driver.
- */
- class I2C {
- private:
- DigitalInOut scl_pin;
- DigitalInOut sda_pin;
-
- uint32_t frequency;
-
- public:
- /**
- * Constructor: SHTx::I2C
- * Create an I2C Master interface, connected to the specified pins.
- * Bit-bang I2C driver to get around the lousy I2C implementation in the
- * SHTx interface...
- *
- * Variables:
- * sda - I2C data line pin
- * scl - I2C clock line pin
- */
- I2C(PinName sda, PinName scl);
-
- /**
- * Function: setFrequency
- * Set the frequency of the SHTx::I2C interface
- *
- * Variables:
- * hz - The bus frequency in hertz
- */
- void setFrequency(uint32_t hz);
-
- /**
- * Function: start
- * Issue start condition on the SHTx::I2C bus
- */
- void start(void);
-
- /**
- * Function: stop
- * Issue stop condition on the SHTx::I2C bus
- */
- void stop(void);
-
- /**
- * Function: wait
- * Wait for SHT15 to complete measurement.
- * Max timeout 500ms.
- *
- * Variables:
- * returns - true if an ACK was received, false otherwise
- */
- bool wait(void);
-
- /**
- * Function: write
- * Write single byte out on the SHTx::I2C bus
- *
- * Variables:
- * data - data to write out on bus
- * returns - true if an ACK was received, false otherwise
- */
- bool write(uint8_t data);
-
- /**
- * Function: write
- * Read single byte form the I2C bus
- *
- * Variables:
- * ack - indicates if the byte is to be acknowledged
- * returns - the read byte
- */
- uint8_t read(bool ack);
-
- private:
- /**
- * Function: output
- * Configures sda pin as output
- */
- void output(void);
-
- /**
- * Function: input
- * Configures sda pin as input
- */
- void input(void);
-
- /**
- * Function: sda
- * Drive sda pin.
- *
- * Variables:
- * value - drive pin high or low
- */
- void sda(bool value);
-
- /**
- * Function: scl
- * Drive scl pin.
- *
- * Variables:
- * value - drive pin high or low
- */
- void scl(bool value);
-
- /**
- * Function: shift_out
- * Write single bit out on the SHTx::I2C bus
- *
- * Variables:
- * bit - value of the bit to be written.
- */
- void shift_out(bool bit);
-
- /**
- * Function: shift_in
- * Read single bit from the SHTx::I2C bus
- *
- * Variables:
- * return - value of the bit read.
- */
- bool shift_in(void);
- };
-}
-
-/* !_I2C_HPP_ */
+/**
+ * Copyright (c) 2010 Roy van Dam <roy@negative-black.org>
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+ */
+
+#ifndef _I2C_HPP_
+#define _I2C_HPP_
+
+#include "mbed.h"
+
+namespace SHTx {
+ /**
+ * Class: I2C
+ * Humidity and Temperature Sensor - SHT15
+ * I2C Bit-bang master driver.
+ */
+ class I2C {
+ private:
+ DigitalInOut scl_pin;
+ DigitalInOut sda_pin;
+
+ uint32_t frequency;
+
+ public:
+ /**
+ * Constructor: SHTx::I2C
+ * Create an I2C Master interface, connected to the specified pins.
+ * Bit-bang I2C driver to get around the lousy I2C implementation in the
+ * SHTx interface...
+ *
+ * Variables:
+ * sda - I2C data line pin
+ * scl - I2C clock line pin
+ */
+ I2C(PinName sda, PinName scl);
+
+ /**
+ * Function: setFrequency
+ * Set the frequency of the SHTx::I2C interface
+ *
+ * Variables:
+ * hz - The bus frequency in hertz
+ */
+ void setFrequency(uint32_t hz);
+
+ /**
+ * Function: start
+ * Issue start condition on the SHTx::I2C bus
+ */
+ void start(void);
+
+ /**
+ * Function: stop
+ * Issue stop condition on the SHTx::I2C bus
+ */
+ void stop(void);
+
+ /**
+ * Function: wait
+ * Wait for SHT15 to complete measurement.
+ * Max timeout 500ms.
+ *
+ * Variables:
+ * returns - true if an ACK was received, false otherwise
+ */
+ bool wait(void);
+
+ /**
+ * Function: reset
+ * If communication with the device is lost
+ * the command will reset the serial interface
+ */
+ void reset(void);
+
+ /**
+ * Function: write
+ * Write single byte out on the SHTx::I2C bus
+ *
+ * Variables:
+ * data - data to write out on bus
+ * returns - true if an ACK was received, false otherwise
+ */
+ bool write(uint8_t data);
+
+ /**
+ * Function: write
+ * Read single byte form the I2C bus
+ *
+ * Variables:
+ * ack - indicates if the byte is to be acknowledged
+ * returns - the read byte
+ */
+ uint8_t read(bool ack);
+
+ private:
+ /**
+ * Function: output
+ * Configures sda pin as output
+ */
+ void output(void);
+
+ /**
+ * Function: input
+ * Configures sda pin as input
+ */
+ void input(void);
+
+ /**
+ * Function: sda
+ * Drive sda pin.
+ *
+ * Variables:
+ * value - drive pin high or low
+ */
+ void sda(bool value);
+
+ /**
+ * Function: scl
+ * Drive scl pin.
+ *
+ * Variables:
+ * value - drive pin high or low
+ */
+ void scl(bool value);
+
+ /**
+ * Function: shift_out
+ * Write single bit out on the SHTx::I2C bus
+ *
+ * Variables:
+ * bit - value of the bit to be written.
+ */
+ void shift_out(bool bit);
+
+ /**
+ * Function: shift_in
+ * Read single bit from the SHTx::I2C bus
+ *
+ * Variables:
+ * return - value of the bit read.
+ */
+ bool shift_in(void);
+ };
+}
+
+/* !_I2C_HPP_ */
#endif
\ No newline at end of file
--- a/sht15.cpp Thu Nov 18 10:23:43 2010 +0000
+++ b/sht15.cpp Fri Nov 19 16:24:46 2010 +0000
@@ -1,220 +1,231 @@
-/**
- * Copyright (c) 2010 Roy van Dam <roy@negative-black.org>
- * 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.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 "sht15.hpp"
-
-namespace SHTx {
- SHT15::SHT15(PinName sda, PinName scl): i2c(sda, scl) {
- this->ready = true;
- wait_ms(11);
- }
-
- float
- SHT15::getTemperature(void) {
- return this->convertTemperature(
- this->temperature,
- this->getFlag(flag_resolution),
- this->scale
- );
- }
-
- float
- SHT15::getHumidity(void) {
- return this->convertHumidity(
- this->humidity,
- this->temperature,
- this->getFlag(flag_resolution)
- );
- }
-
- bool
- SHT15::checkBattery(void) {
- this->readRegister(cmd_read_register);
- return this->getFlag(flag_battery);
- }
-
- bool
- SHT15::setHeater(bool value) {
- this->setFlag(flag_heater, value);
- return this->writeRegister();
- }
-
- bool
- SHT15::setResolution(bool value) {
- this->setFlag(flag_resolution, value);
- return this->writeRegister();
- }
-
- void
- SHT15::setScale(bool value) {
- this->scale = value;
- }
-
- bool
- SHT15::update(void) {
- if ((this->ready == false) ||
- !this->readRegister(cmd_read_temperature) ||
- !this->readRegister(cmd_read_humidity)) {
- return false;
- }
-
- return true;
- }
-
- bool
- SHT15::reset(void) {
- while (this->ready == false) {
- continue;
- }
-
- this->ready = false;
- this->i2c.start();
- bool ack = this->i2c.write(cmd_reset_device);
- this->i2c.stop();
- this->ready = true;
-
- if (ack) {
- this->status_register = 0;
- this->humidity = 0;
- this->temperature = 0;
- wait_ms(11);
- return true;
- }
-
- return false;
- }
-
- float
- SHT15::convertTemperature(uint16_t sot, bool res, bool scale) {
- // Temperature conversion coefficients
- float d1 = this->coefficient.dv[scale];
- float d2 = ((scale) ? this->coefficient.df[res]
- : this->coefficient.dc[res]);
-
- // Temperature data conversion
- return d1 + (d2 * (float)(sot));
- }
-
- float
- SHT15::convertHumidity(uint16_t sohr, uint16_t sot, bool res) {
- // Humidity conversion coefficients
- float c1 = this->coefficient.c1[res];
- float c2 = this->coefficient.c2[res];
- float c3 = this->coefficient.c3[res];
-
- // Temperature compensation coefficients
- float t1 = this->coefficient.t1[res];
- float t2 = this->coefficient.t2[res];
-
- // Temperature data conversion to celcius
- float temp = this->convertTemperature(sot, res, false);
-
- // Humidity data conversion to relative humidity
- float humid = c1 + (c2 * (float)(sohr)) + (c3 * (float)(sohr * sohr));
-
- // Calculate temperature compensation
- return (temp - 25) + (t1 + (t2 * (float)(sohr)) + humid);
- }
-
- bool
- SHT15::writeRegister(void) {
- while (this->ready == false) {
- continue;
- }
-
- this->ready = false;
- this->i2c.start();
-
- if (this->i2c.write(cmd_write_register)) {
- this->i2c.write(this->status_register);
- }
-
- this->i2c.stop();
- this->ready = true;
-
- return true;
- }
-
- bool
- SHT15::readRegister(cmd_list command) {
- while (this->ready == false) {
- continue;
- }
-
- this->ready = false;
- this->i2c.start();
-
- if (!this->i2c.write(command)) {
- this->i2c.stop();
- return false;
- }
-
- switch (command) {
- case cmd_read_temperature: {
- if (!this->i2c.wait()) {
- this->i2c.stop();
- return false;
- }
-
- this->temperature = this->i2c.read(1) << 8;
- this->temperature |= this->i2c.read(0);
- } break;
-
- case cmd_read_humidity: {
- if (!this->i2c.wait()) {
- this->i2c.stop();
- return false;
- }
-
- this->humidity = this->i2c.read(1) << 8;
- this->humidity |= this->i2c.read(0);
- } break;
-
- case cmd_read_register: {
- this->status_register = this->i2c.read(0);
- } break;
- }
-
- this->i2c.stop();
- this->ready = true;
-
- return true;
- }
-
- bool
- SHT15::getFlag(SHT15::flag_list flag) {
- return (this->status_register & flag) ? true : false;
- }
-
- void
- SHT15::setFlag(SHT15::flag_list flag, bool value) {
- if (value) {
- this->status_register |= flag;
- } else {
- this->status_register &= ~flag;
- }
- }
-}
+/**
+ * Copyright (c) 2010 Roy van Dam <roy@negative-black.org>
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 "sht15.hpp"
+
+namespace SHTx {
+ SHT15::SHT15(PinName sda, PinName scl): i2c(sda, scl) {
+ this->ready = true;
+ wait_ms(11);
+ }
+
+ float
+ SHT15::getTemperature(void) {
+ return this->convertTemperature(
+ this->temperature,
+ this->getFlag(flag_resolution),
+ this->scale
+ );
+ }
+
+ float
+ SHT15::getHumidity(void) {
+ return this->convertHumidity(
+ this->humidity,
+ this->temperature,
+ this->getFlag(flag_resolution)
+ );
+ }
+
+ bool
+ SHT15::checkBattery(void) {
+ this->readRegister(cmd_read_register);
+ return this->getFlag(flag_battery);
+ }
+
+ bool
+ SHT15::setHeater(bool value) {
+ this->setFlag(flag_heater, value);
+ return this->writeRegister();
+ }
+
+ bool
+ SHT15::setResolution(bool value) {
+ this->setFlag(flag_resolution, value);
+ return this->writeRegister();
+ }
+
+ bool
+ SHT15::setOTPReload(bool value) {
+ this->setFlag(flag_otp_reload, !value);
+ return this->writeRegister();
+ }
+
+ void
+ SHT15::setScale(bool value) {
+ this->scale = value;
+ }
+
+ bool
+ SHT15::update(void) {
+ if ((this->ready == false) ||
+ !this->readRegister(cmd_read_temperature) ||
+ !this->readRegister(cmd_read_humidity)) {
+ return false;
+ }
+
+ return true;
+ }
+
+ bool
+ SHT15::reset(void) {
+ while (this->ready == false) {
+ continue;
+ }
+
+ this->ready = false;
+ this->i2c.start();
+ bool ack = this->i2c.write(cmd_reset_device);
+ this->i2c.stop();
+ this->ready = true;
+
+ if (ack) {
+ this->status_register = 0;
+ this->humidity = 0;
+ this->temperature = 0;
+ wait_ms(11);
+ return true;
+ }
+
+ return false;
+ }
+
+ void
+ SHT15::connectionReset(void) {
+ this->i2c.reset();
+ }
+
+ float
+ SHT15::convertTemperature(uint16_t sot, bool res, bool scale) {
+ // Temperature conversion coefficients
+ float d1 = this->coefficient.dv[scale];
+ float d2 = ((scale) ? this->coefficient.df[res]
+ : this->coefficient.dc[res]);
+
+ // Temperature data conversion
+ return d1 + (d2 * (float)(sot));
+ }
+
+ float
+ SHT15::convertHumidity(uint16_t sohr, uint16_t sot, bool res) {
+ // Humidity conversion coefficients
+ float c1 = this->coefficient.c1[res];
+ float c2 = this->coefficient.c2[res];
+ float c3 = this->coefficient.c3[res];
+
+ // Temperature compensation coefficients
+ float t1 = this->coefficient.t1[res];
+ float t2 = this->coefficient.t2[res];
+
+ // Temperature data conversion to celcius
+ float temp = this->convertTemperature(sot, res, false);
+
+ // Humidity data conversion to relative humidity
+ float humid = c1 + (c2 * (float)(sohr)) + (c3 * (float)(sohr * sohr));
+
+ // Calculate temperature compensation
+ return (temp - 25) + (t1 + (t2 * (float)(sohr)) + humid);
+ }
+
+ bool
+ SHT15::writeRegister(void) {
+ while (this->ready == false) {
+ continue;
+ }
+
+ this->ready = false;
+ this->i2c.start();
+
+ if (this->i2c.write(cmd_write_register)) {
+ this->i2c.write(this->status_register);
+ }
+
+ this->i2c.stop();
+ this->ready = true;
+
+ return true;
+ }
+
+ bool
+ SHT15::readRegister(cmd_list command) {
+ while (this->ready == false) {
+ continue;
+ }
+
+ this->ready = false;
+ this->i2c.start();
+
+ if (!this->i2c.write(command)) {
+ this->i2c.stop();
+ return false;
+ }
+
+ switch (command) {
+ case cmd_read_temperature: {
+ if (!this->i2c.wait()) {
+ this->i2c.stop();
+ return false;
+ }
+
+ this->temperature = this->i2c.read(1) << 8;
+ this->temperature |= this->i2c.read(0);
+ } break;
+
+ case cmd_read_humidity: {
+ if (!this->i2c.wait()) {
+ this->i2c.stop();
+ return false;
+ }
+
+ this->humidity = this->i2c.read(1) << 8;
+ this->humidity |= this->i2c.read(0);
+ } break;
+
+ case cmd_read_register: {
+ this->status_register = this->i2c.read(0);
+ } break;
+ }
+
+ this->i2c.stop();
+ this->ready = true;
+
+ return true;
+ }
+
+ bool
+ SHT15::getFlag(SHT15::flag_list flag) {
+ return (this->status_register & flag) ? true : false;
+ }
+
+ void
+ SHT15::setFlag(SHT15::flag_list flag, bool value) {
+ if (value) {
+ this->status_register |= flag;
+ } else {
+ this->status_register &= ~flag;
+ }
+ }
+}
--- a/sht15.hpp Thu Nov 18 10:23:43 2010 +0000
+++ b/sht15.hpp Fri Nov 19 16:24:46 2010 +0000
@@ -61,7 +61,7 @@
coefficients(void) {
c1[0] = -2.046f; c2[1] = -2.046f;
c2[0] = 0.036f; c2[1] = 0.587f;
- c3[0] = -0.0000015955f; c2[1] = -0.00040845f;
+ c3[0] = -0.0000015955f; c3[1] = -0.00040845f;
dc[0] = 0.01f; dc[1] = 0.04f;
df[0] = 0.018f; df[1] = 0.072f;
@@ -82,7 +82,7 @@
enum flag_list {
flag_resolution = 0x01,
- flag_reset = 0x02,
+ flag_otp_reload = 0x02,
flag_heater = 0x04,
flag_battery = 0x40
};
@@ -149,6 +149,18 @@
*/
bool setResolution(bool value);
+ /**
+ * Function: setOTPReload
+ * With this operation the calibration data is
+ * uploaded to the register before each measurement. This
+ * may be deactivated for reducing measurement time by
+ * about 10ms
+ *
+ * Values:
+ * value - true->enabled, false->disabled
+ */
+ bool setOTPReload(bool value);
+
/**
* Function: setScale
* Sets output scale to fahrenheit or celcius.
@@ -170,12 +182,21 @@
/**
* Function: reset
- * Performs full chip reset.
+ * Resets the interface, clears the
+ * status register to default values.
+ * And waits for a minimum of 11ms.
*
* Values:
* return - operation result
*/
bool reset(void);
+
+ /**
+ * Function: connectionReset
+ * If communication with the device is lost
+ * the command will reset the serial interface
+ */
+ void connectionReset(void);
private: